*********************************************

                        STRETCHING AND FLEXIBILITY:

                    Everything you never wanted to know

               *********************************************


                             by Brad Appleton

                   Version: 1.32, Last Modified 95/10/23


              Copyright (C) 1993-1995 by Bradford D. Appleton

Permission is granted to make and distribute verbatim copies of this
document at no charge or at a charge that covers reproducing the cost of
the copies, provided that the copyright notice and this permission notice
are preserved on all copies.

This document is available in ascii, texinfo, postscript, dvi, and html
formats via anonymous ftp from the host `cs.huji.ac.il'.  Look under the
directory `/pub/doc/faq/rec/martial.arts'.  The file name matches the
wildcard pattern `stretching.*'.  The file suffix indicates the format. For
WWW users, the URL is:
http://www.cs.huji.ac.il/papers/rma/stretching_toc.html.

Section: Table of Contents
**************************

All section titles in this document begin with the prefix "Section: ".  If
you wish, you may scan ahead to a particular section by searching for the
regular expression /^Section: SECTION-NAME/.  For example, to go to the
unnumbered section named "Introduction", you could scan for
/^Section: Intro/; to go to section 1.1, you could scan for
/^Section: 1\.1/; and to go to appendix A, you could scan for
/^Section: Appendix A/.

This document is organized into the following sections:

     Introduction
          Disclaimer
          Acknowledgements
          About the Author

     1  Physiology of Stretching
          1.1  The Musculoskeletal System
          1.2  Muscle Composition
               1.2.1  How Muscles Contract
               1.2.2  Fast and Slow Muscle Fibers
          1.3  Connective Tissue
          1.4  Cooperating Muscle Groups
          1.5  Types of Muscle Contractions
          1.6  What Happens When You Stretch
               1.6.1  Proprioceptors
               1.6.2  The Stretch Reflex
                    1.6.2.1  Components of the Stretch Reflex
               1.6.3  The Lengthening Reaction
               1.6.4  Reciprocal Inhibition

     2  Flexibility
          2.1  Types of Flexibility
          2.2  Factors Limiting Flexibility
               2.2.1  How Connective Tissue Affects Flexibility
               2.2.2  How Aging Affects Flexibility
          2.3  Strength and Flexibility
               2.3.1  Why Bodybuilders Should Stretch
               2.3.2  Why Contortionists Should Strengthen
          2.4  Overflexibility

     3  Types of Stretching
          3.1  Ballistic Stretching
          3.2  Dynamic Stretching
          3.3  Active Stretching
          3.4  Passive Stretching
          3.5  Static Stretching
          3.6  Isometric Stretching
               3.6.1  How Isometric Stretching Works
          3.7  PNF Stretching
               3.7.1  How PNF Stretching Works

     4  How to Stretch
          4.1  Warming Up
               4.1.1  General Warm-Up
                    4.1.1.1  Joint Rotations
                    4.1.1.2  Aerobic Activity
               4.1.2  Warm-Up Stretching
                    4.1.2.1  Static Warm-Up Stretching
                    4.1.2.2  Dynamic Warm-Up Stretching
               4.1.3  Sport-Specific Activity
          4.2  Cooling Down
          4.3  Massage
          4.4  Elements of a Good Stretch
               4.4.1  Isolation
               4.4.2  Leverage
               4.4.3  Risk
          4.5  Some Risky Stretches
          4.6  Duration, Counting, and Repetition
          4.7  Breathing During Stretching
          4.8  Exercise Order
          4.9  When to Stretch
               4.9.1  Early-Morning Stretching
          4.10  Stretching With a Partner
          4.11  Stretching to Increase Flexibility
          4.12  Pain and Discomfort
               4.12.1  Common Causes of Muscular Soreness
               4.12.2  Stretching with Pain
               4.12.3  Overstretching
          4.13  Performing Splits
               4.13.1  Common Problems When Performing Splits
               4.13.2  The Front Split
               4.13.3  The Side Split
               4.13.4  Split-Stretching Machines

     Appendix A  References on Stretching
          A.1  Recommendations
          A.2  Additional Comments

     Appendix B  Working Toward the Splits
          B.1  lower back stretches
          B.2  lying buttock stretch
          B.3  groin and inner-thigh stretch
          B.4  seated leg stretches
               B.4.1  seated calf stretch
               B.4.2  seated hamstring stretch
               B.4.3  seated inner-thigh stretch
          B.5  psoas stretch
          B.6  quadricep stretch
          B.7  lying `V' stretch

     Appendix C  Normal Ranges of Joint Motion
          C.1  Neck
          C.2  Lumbar Spine
          C.3  Shoulder
          C.4  Elbow
          C.5  Wrist
          C.6  Hip
          C.7  Knee
          C.8  Ankle

     Index

Section: Introduction
*********************

This document is a modest attempt to compile a wealth of information in
order to answer some frequently asked questions about stretching and
flexibility. It is organized into chapters covering the following topics:

  1. Physiology of Stretching

  2. Flexibility

  3. Types of Stretching

  4. How to Stretch

Although each chapter may refer to sections in other chapters, it is not
required that you read every chapter in the order presented. It is
important, however, that you read the disclaimer before reading any other
sections of this document. See [Disclaimer].  If you wish to skip around,
numerous cross references are supplied in each section to help you find the
concepts you may have missed.  There is also an index at the end of this
document.

Section: Disclaimer
===================

I (the author of this document) do *not* claim to be any kind of expert on
stretching, anatomy, physiology, or any other biological science. I am
merely attempting to compile information that I have read in books or that
has been presented to me by knowledgeable sources.

THE TECHNIQUES, IDEAS, AND SUGGESTIONS IN THIS DOCUMENT ARE NOT INTENDED AS
A SUBSTITUTE FOR PROPER MEDICAL ADVICE! CONSULT YOUR PHYSICIAN OR HEALTH
CARE PROFESSIONAL BEFORE PERFORMING ANY NEW EXERCISE OR EXERCISE TECHNIQUE,
PARTICULARLY IF YOU ARE PREGNANT OR NURSING, OR IF YOU ARE ELDERLY, OR IF
YOU HAVE ANY CHRONIC OR RECURRING CONDITIONS. ANY APPLICATION OF THE
TECHNIQUES, IDEAS, AND SUGGESTIONS IN THIS DOCUMENT IS AT THE READER'S SOLE
DISCRETION AND RISK.

THE AUTHOR AND PUBLISHER OF THIS DOCUMENT AND THEIR EMPLOYERS MAKE NO
WARRANTY OF ANY KIND IN REGARD TO THE CONTENT OF THIS DOCUMENT, INCLUDING,
BUT NOT LIMITED TO, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, OR FITNESS
FOR ANY PARTICULAR PURPOSE.  THE AUTHOR AND PUBLISHER OF THIS DOCUMENT AND
THEIR EMPLOYERS ARE NOT LIABLE OR RESPONSIBLE TO ANY PERSON OR ENTITY FOR
ANY ERRORS CONTAINED IN THIS DOCUMENT, OR FOR ANY SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGE CAUSED OR ALLEGED TO BE CAUSED DIRECTLY OR INDIRECTLY
BY THE INFORMATION CONTAINED IN THIS DOCUMENT.

In other words: "I'm not a doctor, nor do I play one on TV!" I can not be
held liable for any damages or injuries that you might suffer from somehow
relying upon information in this document, no matter how awful. Not even if
the information in question is incorrect or inaccurate. If you have any
doubt (and even you you don't) you should always check with your doctor
before trying any new exercise or exercise technique.

Section: Acknowledgements
=========================

Thanks to all the readers of the `rec.martial-arts', `rec.arts.dance' and
`misc.fitness' newsgroups on Usenet who responded to my request for
questions (and answers) on stretching.  Many parts of this document come
directly from these respondents.  Thanks in particular to Shawne Neeper for
sharing her formidable knowledge of muscle anatomy and physiology.

Other portions of this document rely heavily upon the information in the
following books:


     `Sport Stretch', by Michael J. Alter
          (referred to as M. Alter in the rest of this document)
     
     `Stretching Scientifically', by Tom Kurz
          (referred to as Kurz in the rest of this document)
     
     `SynerStretch For Total Body Flexibility', from Health For Life
          (referred to as `SynerStretch' in the rest of this document)
     
     `The Health For Life Training Advisor', also from Health For Life
          (referred to as `HFLTA' in the rest of this document)
     
     `Mobility Training for the Martial Arts', by Tony Gummerson
          (referred to as Gummerson in the rest of this document)

Further information on these books and others, is available near the end of
this document. See Section Appendix A [References on Stretching].

Section: About the Author
=========================

I am *not* an expert in anatomy or physiology!  I do have over 6 years of
martial arts training, and over 20 years of dance training in classical
ballet, modern, and jazz.  However, my primary "qualifications" to write
this document are that I took considerable time and effort to read several
books on the topic, and to combine the information that I read with the
information supplied to me from many knowledgeable readers of Usenet news.
I have tried to write this document for all audiences and not make it
specific to any particular sport or art (such as dancing or martial arts). I
have also tried to leave out any of my own personal opinions or feelings
and just state the facts as related to me by the *real* experts.

I am always interested in hearing about any new information which would be
appropriate to add to this document. If you have any such information about
a stretching technique, a book, or anything else you can think of, please
feel free to contact me. All I ask is that you be prepared to provide me
with at least one reputable and reliable source for your information.

Section: 1  Physiology of Stretching
************************************

The purpose of this chapter is to introduce you to some of the basic
physiological concepts that come into play when a muscle is stretched.
Concepts will be introduced initially with a general overview and then (for
those who want to know the gory details) will be discussed in further
detail. If you aren't all that interested in this aspect of stretching, you
can skip this chapter. Other sections will refer to important concepts from
this chapter and you can easily look them up on a "need to know" basis.

Section: 1.1  The Musculoskeletal System
========================================

Together, muscles and bones comprise what is called the "musculoskeletal
system" of the body. The bones provide posture and structural support for
the body and the muscles provide the body with the ability to move (by
contracting, and thus generating tension). The musculoskeletal system also
provides protection for the body's internal organs. In order to serve their
function, bones must be joined together by something. The point where bones
connect to one another is called a "joint", and this connection is made
mostly by "ligaments" (along with the help of muscles). Muscles are
attached to the bone by "tendons". Bones, tendons, and ligaments do not
possess the ability (as muscles do) to make your body move.  Muscles are
very unique in this respect.

Section: 1.2  Muscle Composition
================================

Muscles vary in shape and in size, and serve many different purposes.  Most
large muscles, like the hamstrings and quadriceps, control motion.  Other
muscles, like the heart, and the muscles of the inner ear, perform other
functions. At the microscopic level however, all muscles share the same
basic structure.

At the highest level, the (whole) muscle is composed of many strands of
tissue called "fascicles". These are the strands of muscle that we see when
we cut red meat or poultry. Each fascicle is composed of "fasciculi" which
are bundles of "muscle fibers".  The muscle fibers are in turn composed of
tens of thousands of thread-like "myofybrils", which can contract, relax,
and elongate (lengthen).  The myofybrils are (in turn) composed of up to
millions of bands laid end-to-end called "sarcomeres". Each sarcomere is
made of overlapping thick and thin filaments called "myofilaments".  The
thick and thin myofilaments are made up of "contractile proteins",
primarily actin and myosin.

Section: 1.2.1  How Muscles Contract
------------------------------------

The way in which all these various levels of the muscle operate is as
follows: Nerves connect the spinal column to the muscle. The place where
the nerve and muscle meet is called the "neuromuscular junction".  When an
electrical signal crosses the neuromuscular junction, it is transmitted
deep inside the muscle fibers. Inside the muscle fibers, the signal
stimulates the flow of calcium which causes the thick and thin myofilaments
to slide across one another. When this occurs, it causes the sarcomere to
shorten, which generates force. When billions of sarcomeres in the muscle
shorten all at once it results in a contraction of the entire muscle fiber.

When a muscle fiber contracts, it contracts completely. There is no such
thing as a partially contracted muscle fiber. Muscle fibers are unable to
vary the intensity of their contraction relative to the load against which
they are acting. If this is so, then how does the force of a muscle
contraction vary in strength from strong to weak?  What happens is that
more muscle fibers are recruited, as they are needed, to perform the job at
hand. The more muscle fibers that are recruited by the central nervous
system, the stronger the force generated by the muscular contraction.

Section: 1.2.2  Fast and Slow Muscle Fibers
-------------------------------------------

The energy which produces the calcium flow in the muscle fibers comes from
"mitochondria", the part of the muscle cell that converts glucose (blood
sugar) into energy. Different types of muscle fibers have different amounts
of mitochondria. The more mitochondria in a muscle fiber, the more energy
it is able to produce. Muscle fibers are categorized into "slow-twitch
fibers" and "fast-twitch fibers".  Slow-twitch fibers (also called "Type 1
muscle fibers") are slow to contract, but they are also very slow to
fatigue.  Fast-twitch fibers are very quick to contract and come in two
varieties: "Type 2A muscle fibers" which fatigue at an intermediate rate,
and "Type 2B muscle fibers" which fatigue very quickly.  The main reason the
slow-twitch fibers are slow to fatigue is that they contain more
mitochondria than fast-twitch fibers and hence are able to produce more
energy. Slow-twitch fibers are also smaller in diameter than fast-twitch
fibers and have increased capillary blood flow around them. Because they
have a smaller diameter and an increased blood flow, the slow-twitch fibers
are able to deliver more oxygen and remove more waste products from the
muscle fibers (which decreases their "fatigability").

These three muscle fiber types (Types 1, 2A, and 2B) are contained in all
muscles in varying amounts.  Muscles that need to be contracted much of the
time (like the heart) have a greater number of Type 1 (slow) fibers. When a
muscle first starts to contract, it is primarily Type 1 fibers that are
initially activated, then Type 2A and Type 2B fibers are activated (if
needed) in that order. The fact that muscle fibers are "recruited" in this
sequence is what provides the ability to execute brain commands with such
fine-tuned tuned muscle responses. It also makes the Type 2B fibers
difficult to train because they are not activated until most of the Type 1
and Type 2A fibers have been recruited.

`HFLTA' states that the the best way to remember the difference between
muscles with predominantly slow-twitch fibers and muscles with
predominantly fast-twitch fibers is to think of "white meat" and "dark
meat". Dark meat is dark because it has a greater number of slow-twitch
muscle fibers and hence a greater number of mitochondria, which are dark.
White meat consists mostly of muscle fibers which are at rest much of the
time but are frequently called on to engage in brief bouts of intense
activity.  This muscle tissue can contract quickly but is fast to fatigue
and slow to recover.  White meat is lighter in color than dark meat because
it contains fewer mitochondria.

Section: 1.3  Connective Tissue
===============================

Located all around the muscle and its fibers are "connective tissues".
Connective tissue is composed of a base substance and two kinds of protein
based fiber. The two types of fiber are "collagenous connective tissue" and
"elastic connective tissue".  Collagenous connective tissue consists mostly
of collagen (hence its name) and provides tensile strength.  Elastic
connective tissue consists mostly of elastin and (as you might guess from
its name) provides elasticity. The base substance is called
"mucopolysaccharide" and acts as both a lubricant (allowing the fibers to
easily slide over one another), and as a glue (holding the fibers of the
tissue together into bundles). The more elastic connective tissue there is
around a joint, the greater the range of motion in that joint.  Connective
tissues are made up of tendons, ligaments, and the fascial sheaths that
envelop, or bind down, muscles into separate groups.  These fascial
sheaths, or "fascia", are named according to where they are located in the
muscles:

"endomysium"
     The innermost fascial sheath that envelops individual muscle fibers.

"perimysium"
     The fascial sheath that binds groups of muscle fibers into individual
     fasciculi (see Section 1.2 [Muscle Composition]).

"epimysium"
     The outermost fascial sheath that binds entire fascicles (see Section
     1.2 [Muscle Composition]).

These connective tissues help provide suppleness and tone to the muscles.

Section: 1.4  Cooperating Muscle Groups
=======================================

When muscles cause a limb to move through the joint's range of motion, they
usually act in the following cooperating groups:

"agonists"
     These muscles cause the movement to occur. They create the normal range
     of movement in a joint by contracting.  Agonists are also referred to
     as "prime movers" since they are the muscles that are primarily
     responsible for generating the movement.

"antagonists"
     These muscles act in opposition to the movement generated by the
     agonists and are responsible for returning a limb to its initial
     position.

"synergists"
     These muscles perform, or assist in performing, the same set of joint
     motion as the agonists. Synergists are sometimes referred to as
     "neutralizers" because they help cancel out, or neutralize, extra
     motion from the agonists to make sure that the force generated works
     within the desired plane of motion.

"fixators"
     These muscles provide the necessary support to assist in holding the
     rest of the body in place while the movement occurs.  Fixators are also
     sometimes called "stabilizers".

As an example, when you flex your knee, your hamstring contracts, and, to
some extent, so does your gastrocnemius (calf) and lower buttocks.
Meanwhile, your quadriceps are inhibited (relaxed and lengthened somewhat)
so as not to resist the flexion (see Section 1.6.4 [Reciprocal
Inhibition]).  In this example, the hamstring serves as the agonist, or
prime mover; the quadricep serves as the antagonist; and the calf and lower
buttocks serve as the synergists.  Agonists and antagonists are usually
located on opposite sides of the affected joint (like your hamstrings and
quadriceps, or your triceps and biceps), while synergists are usually
located on the same side of the joint near the agonists.  Larger muscles
often call upon their smaller neighbors to function as synergists.

The following is a list of commonly used agonist/antagonist muscle pairs:

   * pectorals/latissimus dorsi (pecs and lats)

   * anterior deltoids/posterior deltoids (front and back shoulder)

   * trapezius/deltoids (traps and delts)

   * abdominals/spinal erectors (abs and lower-back)

   * left and right external obliques (sides)

   * quadriceps/hamstrings (quads and hams)

   * shins/calves

   * biceps/triceps

   * forearm flexors/extensors

Section: 1.5  Types of Muscle Contractions
==========================================

The contraction of a muscle does not necessarily imply that the muscle
shortens; it only means that tension has been generated.  Muscles can
contract in the following ways:

"isometric contraction"
     This is a contraction in which no movement takes place, because the
     load on the muscle exceeds the tension generated by the contracting
     muscle.  This occurs when a muscle attempts to push or pull an
     immovable object.

"isotonic contraction"
     This is a contraction in which movement *does* take place, because the
     tension generated by the contracting muscle exceeds the load on the
     muscle. This occurs when you use your muscles to successfully push or
     pull an object.

     Isotonic contractions are further divided into two types:

    "concentric contraction"
          This is a contraction in which the muscle decreases in length
          (shortens) against an opposing load, such as lifting a weight up.

    "eccentric contraction"
          This is a contraction in which the muscle increases in length
          (lengthens) as it resists a load, such as pushing something down.

     During a concentric contraction, the muscles that are shortening serve
     as the agonists and hence do all of the work.  During an eccentric
     contraction the muscles that are lengthening serve as the agonists
     (and do all of the work). See Section 1.4 [Cooperating Muscle Groups].

Section: 1.6  What Happens When You Stretch
===========================================

The stretching of a muscle fiber begins with the sarcomere (see Section 1.2
[Muscle Composition]), the basic unit of contraction in the muscle fiber.
As the sarcomere contracts, the area of overlap between the thick and thin
myofilaments increases.  As it stretches, this area of overlap decreases,
allowing the muscle fiber to elongate.  Once the muscle fiber is at its
maximum resting length (all the sarcomeres are fully stretched), additional
stretching places force on the surrounding connective tissue (see Section
1.3 [Connective Tissue]). As the tension increases, the collagen fibers in
the connective tissue align themselves along the same line of force as the
tension. Hence when you stretch, the muscle fiber is pulled out to its full
length sarcomere by sarcomere, and then the connective tissue takes up the
remaining slack. When this occurs, it helps to realign any disorganized
fibers in the direction of the tension. This realignment is what helps to
rehabilitate scarred tissue back to health.

When a muscle is stretched, some of its fibers lengthen, but other fibers
may remain at rest. The current length of the entire muscle depends upon
the number of stretched fibers (similar to the way that the total strength
of a contracting muscle depends on the number of recruited fibers
contracting). According to `SynerStretch' you should think of "little
pockets of fibers distributed throughout the muscle body stretching, and
other fibers simply going along for the ride". The more fibers that are
stretched, the greater the length developed by the stretched muscle.

Section: 1.6.1  Proprioceptors
------------------------------

The nerve endings that relay all the information about the musculoskeletal
system to the central nervous system are called "proprioceptors".
Proprioceptors (also called "mechanoreceptors") are the source of all
"proprioception": the perception of one's own body position and movement.
The proprioceptors detect any changes in physical displacement (movement or
position) and any changes in tension, or force, within the body. They are
found in all nerve endings of the joints, muscles, and tendons. The
proprioceptors related to stretching are located in the tendons and in the
muscle fibers.

There are two kinds of muscle fibers: "intrafusal muscle fibers" and
"extrafusal muscle fibers". Extrafusil fibers are the ones that contain
myofibrils (see Section 1.2 [Muscle Composition]) and are what is usually
meant when we talk about muscle fibers. Intrafusal fibers are also called
"muscle spindles" and lie parallel to the extrafusal fibers.  Muscle
spindles, or "stretch receptors", are the primary proprioceptors in the
muscle. Another proprioceptor that comes into play during stretching is
located in the tendon near the end of the muscle fiber and is called the
"golgi tendon organ". A third type of proprioceptor, called a "pacinian
corpuscle", is located close to the golgi tendon organ and is responsible
for detecting changes in movement and pressure within the body.

When the extrafusal fibers of a muscle lengthen, so do the intrafusal
fibers (muscle spindles). The muscle spindle contains two different types
of fibers (or stretch receptors) which are sensitive to the change in
muscle length and the rate of change in muscle length.  When muscles
contract it places tension on the tendons where the golgi tendon organ is
located. The golgi tendon organ is sensitive to the change in tension and
the rate of change of the tension.

Section: 1.6.2  The Stretch Reflex
----------------------------------

When the muscle is stretched, so is the muscle spindle (see Section 1.6.1
[Proprioceptors]). The muscle spindle records the change in length (and how
fast) and sends signals to the spine which convey this information.  This
triggers the "stretch reflex" (also called the "myotatic reflex") which
attempts to resist the change in muscle length by causing the stretched
muscle to contract.  The more sudden the change in muscle length, the
stronger the muscle contractions will be (plyometric, or "jump", training
is based on this fact). This basic function of the muscle spindle helps to
maintain muscle tone and to protect the body from injury.

One of the reasons for holding a stretch for a prolonged period of time is
that as you hold the muscle in a stretched position, the muscle spindle
habituates (becomes accustomed to the new length) and reduces its
signaling.  Gradually, you can train your stretch receptors to allow
greater lengthening of the muscles.

Some sources suggest that with extensive training, the stretch reflex of
certain muscles can be controlled so that there is little or no reflex
contraction in response to a sudden stretch. While this type of control
provides the opportunity for the greatest gains in flexibility, it also
provides the greatest risk of injury if used improperly. Only consummate
professional athletes and dancers at the top of their sport (or art) are
believed to actually possess this level of muscular control.

Section: 1.6.2.1  Components of the Stretch Reflex
..................................................

The stretch reflex has both a dynamic component and a static component.
The static component of the stretch reflex persists as long as the muscle
is being stretched.  The dynamic component of the stretch reflex (which can
be very powerful) lasts for only a moment and is in response to the initial
sudden increase in muscle length.  The reason that the stretch reflex has
two components is because there are actually two kinds of intrafusal muscle
fibers: "nuclear chain fibers", which are responsible for the static
component; and "nuclear bag fibers", which are responsible for the dynamic
component.

Nuclear chain fibers are long and thin, and lengthen steadily when
stretched. When these fibers are stretched, the stretch reflex nerves
increase their firing rates (signaling) as their length steadily increases.
This is the static component of the stretch reflex.

Nuclear bag fibers bulge out at the middle, where they are the most
elastic.  The stretch-sensing nerve ending for these fibers is wrapped
around this middle area, which lengthens rapidly when the fiber is
stretched.  The outer-middle areas, in contrast, act like they are filled
with viscous fluid; they resist fast stretching, then gradually extend
under prolonged tension.  So, when a fast stretch is demanded of these
fibers, the middle takes most of the stretch at first; then, as the
outer-middle parts extend, the middle can shorten somewhat.  So the nerve
that senses stretching in these fibers fires rapidly with the onset of a
fast stretch, then slows as the middle section of the fiber is allowed to
shorten again.  This is the dynamic component of the stretch reflex: a
strong signal to contract at the onset of a rapid increase in muscle
length, followed by slightly "higher than normal" signaling which gradually
decreases as the rate of change of the muscle length decreases.

Section: 1.6.3  The Lengthening Reaction
----------------------------------------

When muscles contract (possibly due to the stretch reflex), they produce
tension at the point where the muscle is connected to the tendon, where the
golgi tendon organ is located. The golgi tendon organ records the change in
tension, and the rate of change of the tension, and sends signals to the
spine to convey this information (see Section 1.6.1 [Proprioceptors]).
When this tension exceeds a certain threshold, it triggers the "lengthening
reaction" which inhibits the muscles from contracting and causes them to
relax.  Other names for this reflex are the "inverse myotatic reflex",
"autogenic inhibition", and the "clasped-knife reflex".  This basic
function of the golgi tendon organ helps to protect the muscles, tendons,
and ligaments from injury.  The lengthening reaction is possible only
because the signaling of golgi tendon organ to the spinal cord is powerful
enough to overcome the signaling of the muscle spindles telling the muscle
to contract.

Another reason for holding a stretch for a prolonged period of time is to
allow this lengthening reaction to occur, thus helping the stretched
muscles to relax. It is easier to stretch, or lengthen, a muscle when it is
not trying to contract.

Section: 1.6.4  Reciprocal Inhibition
-------------------------------------

When an agonist contracts, in order to cause the desired motion, it usually
forces the antagonists to relax (see Section 1.4 [Cooperating Muscle
Groups]). This phenomenon is called "reciprocal inhibition" because the
antagonists are inhibited from contracting. This is sometimes called
"reciprocal innervation" but that term is really a misnomer since it is the
agonists which inhibit (relax) the antagonists. The antagonists do *not*
actually innervate (cause the contraction of) the agonists.

Such inhibition of the antagonistic muscles is not necessarily required.
In fact, co-contraction can occur. When you perform a sit-up, one would
normally assume that the stomach muscles inhibit the contraction of the
muscles in the lumbar, or lower, region of the back. In this particular
instance however, the back muscles (spinal erectors) also contract. This is
one reason why sit-ups are good for strengthening the back as well as the
stomach.

When stretching, it is easier to stretch a muscle that is relaxed than to
stretch a muscle that is contracting.  By taking advantage of the
situations when reciprocal inhibition *does* occur, you can get a more
effective stretch by inducing the antagonists to relax during the stretch
due to the contraction of the agonists.  You also want to relax any muscles
used as synergists by the muscle you are trying to stretch.  For example,
when you stretch your calf, you want to contract the shin muscles (the
antagonists of the calf) by flexing your foot. However, the hamstrings use
the calf as a synergist so you want to also relax the hamstrings by
contracting the quadricep (i.e., keeping your leg straight).

Section: 2  Flexibility
***********************

Flexibility is defined by Gummerson as "the absolute range of movement in a
joint or series of joints that is attainable in a momentary effort with the
help of a partner or a piece of equipment." This definition tells us that
flexibility is not something general but is specific to a particular joint
or set of joints. In other words, it is a myth that some people are
innately flexible throughout their entire body. Being flexible in one
particular area or joint does not necessarily imply being flexible in
another. Being "loose" in the upper body does not mean you will have a
"loose" lower body. Furthermore, according to `SynerStretch', flexibility
in a joint is also "specific to the action performed at the joint (the
ability to do front splits doesn't imply the ability to do side splits even
though both actions occur at the hip)."

Section: 2.1  Types of Flexibility
==================================

Many people are unaware of the fact that there are different types of
flexibility. These different types of flexibility are grouped according to
the various types of activities involved in athletic training. The ones
which involve motion are called "dynamic" and the ones which do not are
called "static". The different types of flexibility (according to Kurz) are:

"dynamic flexibility"
     Dynamic flexibility (also called "kinetic flexibility") is the ability
     to perform dynamic (or kinetic) movements of the muscles to bring a
     limb through its full range of motion in the joints.

"static-active flexibility"
     Static-active flexibility (also called "active flexibility") is the
     ability to assume and maintain extended positions using only the
     tension of the agonists and synergists while the antagonists are being
     stretched (see Section 1.4 [Cooperating Muscle Groups]). For example,
     lifting the leg and keeping it high without any external support
     (other than from your own leg muscles).

"static-passive flexibility"
     Static-passive flexibility (also called "passive flexibility") is the
     ability to assume extended positions and then maintain them using only
     your weight, the support of your limbs, or some other apparatus (such
     as a chair or a barre). Note that the ability to maintain the position
     does not come solely from your muscles, as it does with static-active
     flexibility.  Being able to perform the splits is an example of
     static-passive flexibility.

Research has shown that active flexibility is more closely related to the
level of sports achievement than is passive flexibility.  Active
flexibility is harder to develop than passive flexibility (which is what
most people think of as "flexibility"); not only does active flexibility
require passive flexibility in order to assume an initial extended
position, it also requires muscle strength to be able to hold and maintain
that position.

Section: 2.2  Factors Limiting Flexibility
==========================================

According to Gummerson, flexibility (he uses the term "mobility") is
affected by the following factors:

   * Internal influences

        - the type of joint (some joints simply aren't meant to be flexible)

        - the internal resistance within a joint

        - bony structures which limit movement

        - the elasticity of muscle tissue (muscle tissue that is scarred
          due to a previous injury is not very elastic)

        - the elasticity of tendons and ligaments (ligaments do not stretch
          much and tendons should not stretch at all)

        - the elasticity of skin (skin actually has some degree of
          elasticity, but not much)

        - the ability of a muscle to relax and contract to achieve the
          greatest range of movement

        - the temperature of the joint and associated tissues (joints and
          muscles offer better flexibility at body temperatures that are 1
          to 2 degrees higher than normal)

   * External influences

        - the temperature of the place where one is training (a warmer
          temperature is more conducive to increased flexibility)

        - the time of day (most people are more flexible in the afternoon
          than in the morning, peaking from about 2:30pm-4pm)

        - the stage in the recovery process of a joint (or muscle) after
          injury (injured joints and muscles will usually offer a lesser
          degree of flexibility than healthy ones)

        - age (pre-adolescents are generally more flexible than adults)

        - gender (females are generally more flexible than males)

        - one's ability to perform a particular exercise (practice makes
          perfect)

        - one's commitment to achieving flexibility

        - the restrictions of any clothing or equipment

Some sources also the suggest that water is an important dietary element
with regard to flexibility. Increased water intake is believed to
contribute to increased mobility, as well as increased total body
relaxation.

Rather than discuss each of these factors in significant detail as
Gummerson does, I will attempt to focus on some of the more common factors
which limit one's flexibility.  According to `SynerStretch', the most
common factors are: bone structure, muscle mass, excess fatty tissue, and
connective tissue (and, of course, physical injury or disability).

Depending on the type of joint involved and its present condition (is it
healthy?), the bone structure of a particular joint places very noticeable
limits on flexibility. This is a common way in which age can be a factor
limiting flexibility since older joints tend not to be as healthy as
younger ones.

Muscle mass can be a factor when the muscle is so heavily developed that it
interferes with the ability to take the adjacent joints through their
complete range of motion (for example, large hamstrings limit the ability
to fully bend the knees). Excess fatty tissue imposes a similar restriction.

The majority of "flexibility" work should involve performing exercises
designed to reduce the internal resistance offered by soft connective
tissues (see Section 1.3 [Connective Tissue]). Most stretching exercises
attempt to accomplish this goal and can be performed by almost anyone,
regardless of age or gender.

Section: 2.2.1  How Connective Tissue Affects Flexibility
---------------------------------------------------------

The resistance to lengthening that is offered by a muscle is dependent upon
its connective tissues: When the muscle elongates, the surrounding
connective tissues become more taut (see Section 1.3 [Connective Tissue]).
Also, inactivity of certain muscles or joints can cause chemical changes in
connective tissue which restrict flexibility.  According to M. Alter, each
type of tissue plays a certain role in joint stiffness: "The joint capsule
(i.e., the saclike structure that encloses the ends of bones) and ligaments
are the most important factors, accounting for 47 percent of the stiffness,
followed by the muscle's fascia (41 percent), the tendons (10 percent), and
skin (2 percent)".

M. Alter goes on to say that efforts to increase flexibility should be
directed at the muscle's fascia however. This is because it has the most
elastic tissue, and because ligaments and tendons (since they have less
elastic tissue) are not intended to stretched very much at all.
Overstretching them may weaken the joint's integrity and cause
destabilization (which increases the risk of injury).

When connective tissue is overused, the tissue becomes fatigued and may
tear, which also limits flexibility.  When connective tissue is unused or
under used, it provides significant resistance and limits flexibility.  The
elastin begins to fray and loses some of its elasticity, and the collagen
increases in stiffness and in density.  Aging has some of the same effects
on connective tissue that lack of use has.

Section: 2.2.2  How Aging Affects Flexibility
---------------------------------------------

With appropriate training, flexibility can, and should, be developed at all
ages. This does not imply, however, that flexibility can be developed at
the same rate by everyone. In general, the older you are, the longer it
will take to develop the desired level of flexibility. Hopefully, you'll be
more patient if you're older.

According to M. Alter, the main reason we become less flexible as we get
older is a result of certain changes that take place in our connective
tissues. As we age, our bodies gradually dehydrate to some extent.  It is
believed that "stretching stimulates the production or retention of
lubricants between the connective tissue fibers, thus preventing the
formation of adhesions". Hence, exercise can delay some of the loss of
flexibility that occurs due to the aging process.

M. Alter further states that some of the physical changes attributed to
aging are the following:

   * An increased amount of calcium deposits, adhesions, and cross-links in
     the body

   * An increase in the level of fragmentation and dehydration

   * Changes in the chemical structure of the tissues.

   * Loss of "suppleness" due to the replacement of muscle fibers with
     fatty, collagenous fibers.

This does *not* mean that you should give up trying to achieve flexibility
if you are old or inflexible. It just means that you need to work harder,
and more carefully, for a longer period of time when attempting to increase
flexibility. Increases in the ability of muscle tissues and connective
tissues to elongate (stretch) can be achieved at any age.

Section: 2.3  Strength and Flexibility
======================================

Strength training and flexibility training should go hand in hand.  It is a
common misconception that there must always be a trade-off between
flexibility and strength. Obviously, if you neglect flexibility training
altogether in order to train for strength then you are certainly
sacrificing flexibility (and vice versa).  However, performing exercises
for both strength and flexibility need not sacrifice either one.  As a
matter of fact, flexibility training and strength training can actually
enhance one another.

Section: 2.3.1  Why Bodybuilders Should Stretch
-----------------------------------------------

One of the best times to stretch is right after a strength workout such as
weightlifting. Static stretching of fatigued muscles (see Section 3.5
[Static Stretching]) performed immediately following the exercise(s) that
caused the fatigue, helps not only to increase flexibility, but also
enhances the promotion of muscular development (muscle growth), and will
actually help decrease the level of post-exercise soreness.  Here's why:

After you have used weights (or other means) to overload and fatigue your
muscles, your muscles retain a "pump" and are shortened somewhat.  This
"shortening" is due mostly to the repetition of intense muscle activity
that often only takes the muscle through part of its full range of motion.
This "pump" makes the muscle appear bigger. The "pumped" muscle is also
full of lactic acid and other by-products from exhaustive exercise. If the
muscle is not stretched afterward, it will retain this decreased range of
motion (it sort of "forgets" how to make itself as long as it could) and
the buildup of lactic acid will cause post-exercise soreness. Static
stretching of the "pumped" muscle helps it to become "looser", and to
"remember" its full range of movement. It also helps to remove lactic acid
and other waste-products from the muscle. While it is true that stretching
the "pumped" muscle will make it appear visibly smaller, it does not
decrease the muscle's size or inhibit muscle growth. It merely reduces the
"tightness" (contraction) of the muscles so that they do not "bulge" as
much.

Also, strenuous workouts will often cause damage to the muscle's connective
tissue. The tissue heals in 1 to 2 days but it is believed that the tissues
heal at a shorter length (decreasing muscular development as well as
flexibility). To prevent the tissues from healing at a shorter length,
physiologists recommend static stretching after strength workouts.

Section: 2.3.2  Why Contortionists Should Strengthen
----------------------------------------------------

You should be "tempering" (or balancing) your flexibility training with
strength training (and vice versa). Do not perform stretching exercises for
a given muscle group without also performing strength exercises for that
same group of muscles. Judy Alter, in her book `Stretch and Strengthen',
recommends stretching muscles after performing strength exercises, and
performing strength exercises for every muscle you stretch. In other words:
"Strengthen what you stretch, and stretch after you strengthen!"

The reason for this is that flexibility training on a regular basis causes
connective tissues to stretch which in turn causes them to loosen (become
less taut) and elongate. When the connective tissue of a muscle is weak, it
is more likely to become damaged due to overstretching, or sudden, powerful
muscular contractions. The likelihood of such injury can be prevented by
strengthening the muscles bound by the connective tissue. Kurz suggests
dynamic strength training consisting of light dynamic exercises with
weights (lots of reps, not too much weight), and isometric tension
exercises.  If you also lift weights, dynamic strength training for a
muscle should occur *before* subjecting that muscle to an intense
weightlifting workout. This helps to pre-exhaust the muscle first, making
it easier (and faster) to achieve the desired overload in an intense
strength workout.  Attempting to perform dynamic strength training *after*
an intense weightlifting workout would be largely ineffective.

If you are working on increasing (or maintaining) flexibility then it is
*very* important that your strength exercises force your muscles to take
the joints through their full range of motion.  According to Kurz,
Repeating movements that do not employ a full range of motion in the joints
(like cycling, certain weightlifting techniques, and pushups) can cause of
shortening of the muscles surrounding the joints. This is because the
nervous control of length and tension in the muscles are set at what is
repeated most strongly and/or most frequently.

Section: 2.4  Overflexibility
=============================

It is possible for the muscles of a joint to become too flexible.
According to `SynerStretch', there is a tradeoff between flexibility and
stability. As you get "looser" or more limber in a particular joint, less
support is given to the joint by its surrounding muscles. Excessive
flexibility can be just as bad as not enough because both increase your
risk of injury.

Once a muscle has reached its absolute maximum length, attempting to
stretch the muscle further only serves to stretch the ligaments and put
undue stress upon the tendons (two things that you do *not* want to
stretch). Ligaments will tear when stretched more than 6% of their normal
length. Tendons are not even supposed to be able to lengthen.  Even when
stretched ligaments and tendons do not tear, loose joints and/or a decrease
in the joint's stability can occur (thus vastly increasing your risk of
injury).

Once you have achieved the desired level of flexibility for a muscle or set
of muscles and have maintained that level for a solid week, you should
discontinue any isometric or PNF stretching of that muscle until some of
its flexibility is lost (see Section 3.6 [Isometric Stretching], and see
Section 3.7 [PNF Stretching]).

Section: 3  Types of Stretching
*******************************

Just as there are different types of flexibility, there are also different
types of stretching. Stretches are either dynamic (meaning they involve
motion) or static (meaning they involve no motion).  Dynamic stretches
affect dynamic flexibility and static stretches affect static flexibility
(and dynamic flexibility to some degree).

The different types of stretching are:

  1. ballistic stretching

  2. dynamic stretching

  3. active stretching

  4. passive (or relaxed) stretching

  5. static stretching

  6. isometric stretching

  7. PNF stretching

Section: 3.1  Ballistic Stretching
==================================

Ballistic stretching uses the momentum of a moving body or a limb in an
attempt to force it beyond its normal range of motion.  This is stretching,
or "warming up", by bouncing into (or out of) a stretched position, using
the stretched muscles as a spring which pulls you out of the stretched
position.  (e.g. bouncing down repeatedly to touch your toes.)  This type
of stretching is not considered useful and can lead to injury.  It does not
allow your muscles to adjust to, and relax in, the stretched position.  It
may instead cause them to tighten up by repeatedly activating the stretch
reflex (see Section 1.6.2 [The Stretch Reflex]).

Section: 3.2  Dynamic Stretching
================================

"Dynamic stretching", according to Kurz, "involves moving parts of your
body and gradually increasing reach, speed of movement, or both." Do not
confuse dynamic stretching with ballistic stretching!  Dynamic stretching
consists of controlled leg and arm swings that take you (gently!) to the
limits of your range of motion.  Ballistic stretches involve trying to
force a part of the body *beyond* its range of motion.  In dynamic
stretches, there are no bounces or "jerky" movements.  An example of
dynamic stretching would be slow, controlled leg swings, arm swings, or
torso twists.

Dynamic stretching improves dynamic flexibility and is quite useful as part
of your warm-up for an active or aerobic workout (such as a dance or
martial-arts class). See Section 4.1 [Warming Up].

According to Kurz, dynamic stretching exercises should be performed in sets
of 8-12 repetitions. Be sure to stop when and if you feel tired. Tired
muscles have less elasticity which decreases the range of motion used in
your movements. Continuing to exercise when you are tired serves only to
reset the nervous control of your muscle length at the reduced range of
motion used in the exercise (and will cause a loss of flexibility). Once
you attain a maximal range of motion for a joint in any direction you
should stop doing that movement during that workout. Tired and overworked
muscles won't attain a full range of motion and the muscle's kinesthetic
memory will remember the repeated shorted range of motion, which you will
then have to overcome before you can make further progress.

Section: 3.3  Active Stretching
===============================

"Active stretching" is also referred to as "static-active stretching".  An
active stretch is one where you assume a position and then hold it there
with no assistance other than using the strength of your agonist muscles
(see Section 1.4 [Cooperating Muscle Groups]). For example, bringing your
leg up high and then holding it there without anything (other than your leg
muscles themselves) to keep the leg in that extended position.  The tension
of the agonists in an active stretch helps to relax the muscles being
stretched (the antagonists) by reciprocal inhibition (see Section 1.6.4
[Reciprocal Inhibition]).

Active stretching increases active flexibility and strengthens the
agonistic muscles. Active stretches are usually quite difficult to hold and
maintain for more than 10 seconds and rarely need to be held any longer
than 15 seconds.

Many of the movements (or stretches) found in various forms of yoga are
active stretches.

Section: 3.4  Passive Stretching
================================

"Passive stretching" is also referred to as "relaxed stretching", and as
"static-passive stretching". A passive stretch is one where you assume a
position and hold it with some other part of your body, or with the
assistance of a partner or some other apparatus. For example, bringing your
leg up high and then holding it there with your hand. The splits is an
example of a passive stretch (in this case the floor is the "apparatus"
that you use to maintain your extended position).

Slow, relaxed stretching is useful in relieving spasms in muscles that are
healing after an injury. Obviously, you should check with your doctor first
to see if it is okay to attempt to stretch the injured muscles (see Section
4.12 [Pain and Discomfort]).

Relaxed stretching is also very good for "cooling down" after a workout and
helps reduce post-workout muscle fatigue, and soreness.  See Section 4.2
[Cooling Down].

Section: 3.5  Static Stretching
===============================

Many people use the term "passive stretching" and "static stretching"
interchangeably. However, there are a number of people who make a
distinction between the two.  According to M. Alter, "Static stretching"
consists of stretching a muscle (or group of muscles) to its farthest point
and then maintaining or holding that position, whereas "Passive stretching"
consists of a relaxed person who is relaxed (passive) while some external
force (either a person or an apparatus) brings the joint through its range
of motion.

Notice that the definition of passive stretching given in the previous
section encompasses *both* of the above definitions.  Throughout this
document, when the term "static stretching" or "passive stretching" is
used, its intended meaning is the definition of passive stretching as
described in the previous section. You should be aware of these alternative
meanings, however, when looking at other references on stretching.

Section: 3.6  Isometric Stretching
==================================

"Isometric stretching" is a type of static stretching (meaning it does not
use motion) which involves the resistance of muscle groups through
isometric contractions (tensing) of the stretched muscles (see Section 1.5
[Types of Muscle Contractions]).  The use of isometric stretching is one of
the fastest ways to develop increased static-passive flexibility and is
much more effective than either passive stretching or active stretching
alone.  Isometric stretches also help to develop strength in the "tensed"
muscles (which helps to develop static-active flexibility), and seems to
decrease the amount of pain usually associated with stretching.

The most common ways to provide the needed resistance for an isometric
stretch are to apply resistance manually to one's own limbs, to have a
partner apply the resistance, or to use an apparatus such as a wall (or the
floor) to provide resistance.

An example of manual resistance would be holding onto the ball of your foot
to keep it from flexing while you are using the muscles of your calf to try
and straighten your instep so that the toes are pointed.

An example of using a partner to provide resistance would be having a
partner hold your leg up high (and keep it there) while you attempt to
force your leg back down to the ground.

An example of using the wall to provide resistance would be the well known
"push-the-wall" calf-stretch where you are actively attempting to move the
wall (even though you know you can't).

Isometric stretching is *not* recommended for children and adolescents
whose bones are still growing. These people are usually already flexible
enough that the strong stretches produced by the isometric contraction have
a much higher risk of damaging tendons and connective tissue.  Kurz
strongly recommends preceding any isometric stretch of a muscle with
dynamic strength training for the muscle to be stretched. A full session of
isometric stretching makes a lot of demands on the muscles being stretched
and should not be performed more than once per day for a given group of
muscles (ideally, no more than once every 36 hours).

The proper way to perform an isometric stretch is as follows:

  1. Assume the position of a passive stretch for the desired muscle.

  2. Next, tense the stretched muscle for 7-15 seconds (resisting against
     some force that will not move, like the floor or a partner).

  3. Finally, relax the muscle for at least 20 seconds.


Some people seem to recommend holding the isometric contraction for longer
than 15 seconds, but according to `SynerStretch' (the videotape), research
has shown that this is not necessary. So you might as well make your
stretching routine less time consuming.

Section: 3.6.1  How Isometric Stretching Works
----------------------------------------------

Recall from our previous discussion (see Section 1.2.1 [How Muscles
Contract]) that there is no such thing as a partially contracted muscle
fiber: when a muscle is contracted, some of the fibers contract and some
remain at rest (more fibers are recruited as the load on the muscle
increases).  Similarly, when a muscle is stretched, some of the fibers are
elongated and some remain at rest (see Section 1.6 [What Happens When You
Stretch]). During an isometric contraction, some of the resting fibers are
being pulled upon from both ends by the muscles that are contracting. The
result is that some of those resting fibers stretch!

Normally, the handful of fibers that stretch during an isometric
contraction are not very significant.  The true effectiveness of the
isometric contraction occurs when a muscle that is already in a stretched
position is subjected to an isometric contraction. In this case, some of
the muscle fibers are already stretched before the contraction, and, if
held long enough, the initial passive stretch overcomes the stretch reflex
(see Section 1.6.2 [The Stretch Reflex]) and triggers the lengthening
reaction (see Section 1.6.3 [The Lengthening Reaction]), inhibiting the
stretched fibers from contracting.  At this point, according to
`SynerStretch', when you isometrically contracted, some resting fibers
would contract and some resting fibers would stretch.  Furthermore, many of
the fibers already stretching may be prevented from contracting by the
inverse myotatic reflex (the lengthening reaction) and would stretch even
more. When the isometric contraction is completed, the contracting fibers
return to their resting length but the stretched fibers would remember
their stretched length and (for a period of time) retain the ability to
elongate past their previous limit. This enables the entire muscle to
stretch beyonds its initial maximum and results in increased flexibility.

The reason that the stretched fibers develop and retain the ability to
stretch beyond their normal limit during an isometric stretch has to do
with the muscle spindles (see Section 1.6.1 [Proprioceptors]): The signal
which tells the muscle to contract voluntarily, also tells the muscle
spindle's (intrafusal) muscle fibers to shorten, increasing sensitivity of
the stretch reflex.  This mechanism normally maintains the sensitivity of
the muscle spindle as the muscle shortens during contraction. This allows
the muscle spindles to habituate (become accustomed) to an even
further-lengthened position.

Section: 3.7  PNF Stretching
============================

PNF stretching is currently the fastest and most effective way known to
increase static-passive flexibility.  PNF is an acronym for "proprioceptive
neuromuscular facilitation".  It is not really a type of stretching but is
a technique of combining passive stretching (see Section 3.4 [Passive
Stretching]) and isometric stretching (see Section 3.6 [Isometric
Stretching]) in order to achieve maximum static flexibility.  Actually, the
term PNF stretching is itself a misnomer.  PNF was initially developed as a
method of rehabilitating stroke victims.  PNF refers to any of several
"post-isometric relaxation" stretching techniques in which a muscle group
is passively stretched, then contracts isometrically against resistance
while in the stretched position, and then is passively stretched again
through the resulting increased range of motion. PNF stretching usually
employs the use of a partner to provide resistance against the isometric
contraction and then later to passively take the joint through its
increased range of motion.  It may be performed, however, without a
partner, although it is usually more effective with a partner's assistance.

Most PNF stretching techniques employ "isometric agonist
contraction/relaxation" where the stretched muscles are contracted
isometrically and then relaxed. Some PNF techniques also employ "isometric
antagonist contraction" where the antagonists of the stretched muscles are
contracted. In all cases, it is important to note that the stretched muscle
should be rested (and relaxed) for at least 20 seconds before performing
another PNF technique.  The most common PNF stretching techniques are:

the "hold-relax"
     This technique is also called the "contract-relax".  After assuming an
     initial passive stretch, the muscle being stretched is isometrically
     contracted for 7-15 seconds, after which the muscle is briefly relaxed
     for 2-3 seconds, and then immediately subjected to a passive stretch
     which stretches the muscle even further than the initial passive
     stretch.  This final passive stretch is held for 10-15 seconds. The
     muscle is then relaxed for 20 seconds before performing another PNF
     technique.

the "hold-relax-contract"
     This technique is also called the "contract-relax-contract", and the
     "contract-relax-antagonist-contract" (or "CRAC"). It involves
     performing two isometric contractions: first of the agonists, then, of
     the antagonists. The first part is similar to the hold-relax where,
     after assuming an initial passive stretch, the stretched muscle is
     isometrically contracted for 7-15 seconds. Then the muscle is relaxed
     while its antagonist immediately performs an isometric contraction that
     is held for 7-15 seconds.  The muscles are then relaxed for 20 seconds
     before performing another PNF technique.

the "hold-relax-swing"
     This technique (and a similar technique called the "hold-relax-bounce")
     actually involves the use of dynamic or ballistic stretches in
     conjunction with static and isometric stretches. It is *very* risky,
     and is successfully used only by the most advanced of athletes and
     dancers that have managed to achieve a high level of control over
     their muscle stretch reflex (see Section 1.6.2 [The Stretch Reflex]).
     It is similar to the hold-relax technique except that a dynamic or
     ballistic stretch is employed in place of the final passive stretch.

Notice that in the hold-relax-contract, there is no final passive stretch.
It is replaced by the antagonist-contraction which, via reciprocal
inhibition (see Section 1.6.4 [Reciprocal Inhibition]), serves to relax and
further stretch the muscle that was subjected to the initial passive
stretch.  Because there is no final passive stretch, this PNF technique is
considered one of the safest PNF techniques to perform (it is less likely
to result in torn muscle tissue).  Some people like to make the technique
even more intense by adding the final passive stretch after the second
isometric contraction.  Although this can result in greater flexibility
gains, it also increases the likelihood of injury.

Even more risky are dynamic and ballistic PNF stretching techniques like
the hold-relax-swing, and the hold-relax-bounce. If you are not a
professional athlete or dancer, you probably have no business attempting
either of these techniques (the likelihood of injury is just too great).
Even professionals should not attempt these techniques without the guidance
of a professional coach or training advisor. These two techniques have the
greatest potential for rapid flexibility gains, but only when performed by
people who have a sufficiently high level of control of the stretch reflex
in the muscles that are being stretched.

Like isometric stretching (see Section 3.6 [Isometric Stretching]), PNF
stretching is also not recommended for children and people whose bones are
still growing (for the same reasons.  Also like isometric stretching, PNF
stretching helps strengthen the muscles that are contracted and therefore
is good for increasing active flexibility as well as passive flexibility.
Furthermore, as with isometric stretching, PNF stretching is very strenuous
and should be performed for a given muscle group no more than once per day
(ideally, no more than once per 36 hour period).

The initial recommended procedure for PNF stretching is to perform the
desired PNF technique 3-5 times for a given muscle group (resting 20
seconds between each repetition).  However, `HFLTA' cites a 1987 study
whose results suggest that performing 3-5 repetitions of a PNF technique
for a given muscle group is not necessarily any more effective than
performing the technique only once. As a result, in order to decrease the
amount of time taken up by your stretching routine (without decreasing its
effectiveness), `HFLTA' recommends performing only one PNF technique per
muscle group stretched in a given stretching session.

Section: 3.7.1  How PNF Stretching Works
----------------------------------------

Remember that during an isometric stretch, when the muscle performing the
isometric contraction is relaxed, it retains its ability to stretch beyond
its initial maximum length (see Section 3.6.1 [How Isometric Stretching
Works]). Well, PNF tries to take immediate advantage of this increased
range of motion by immediately subjecting the contracted muscle to a
passive stretch.

The isometric contraction of the stretched muscle accomplishes several
things:

  1. As explained previously (see Section 3.6.1 [How Isometric Stretching
     Works]), it helps to train the stretch receptors of the muscle spindle
     to immediately accommodate a greater muscle length.

  2. The intense muscle contraction, and the fact that it is maintained for
     a period of time, serves to fatigue many of the fast-twitch fibers of
     the contracting muscles (see Section 1.2.2 [Fast and Slow Muscle
     Fibers]).  This makes it harder for the fatigued muscle fibers to
     contract in resistance to a subsequent stretch (see Section 1.6.2 [The
     Stretch Reflex]).

  3. The tension generated by the contraction activates the golgi tendon
     organ (see Section 1.6.1 [Proprioceptors]), which inhibits contraction
     of the muscle via the lengthening reaction (see Section 1.6.3 [The
     Lengthening Reaction]).  Voluntary contraction during a stretch
     increases tension on the muscle, activating the golgi tendon organs
     more than the stretch alone.  So, when the voluntary contraction is
     stopped, the muscle is even more inhibited from contracting against a
     subsequent stretch.


PNF stretching techniques take advantage of the sudden "vulnerability" of
the muscle and its increased range of motion by using the period of time
immediately following the isometric contraction to train the stretch
receptors to get used to this new, increased, range of muscle length. This
is what the final passive (or in some cases, dynamic) stretch accomplishes.

Section: 4  How to Stretch
**************************

When done properly, stretching can do more than just increase flexibility.
According to M. Alter, benefits of stretching include:

   * enhanced physical fitness

   * enhanced ability to learn and perform skilled movements

   * increased mental and physical relaxation

   * enhanced development of body awareness

   * reduced risk of injury to joints, muscles, and tendons

   * reduced muscular soreness

   * reduced muscular tension

   * increased suppleness due to stimulation of the production of chemicals
     which lubricate connective tissues (see Section 1.3 [Connective
     Tissue])

   * reduced severity of painful menstruation ("dysmenorrhea") in females

Unfortunately, even those who stretch do not always stretch properly and
hence do not reap some or all of these benefits.  Some of the most common
mistakes made when stretching are:

   * improper warm-up

   * inadequate rest between workouts

   * overstretching

   * performing the wrong exercises

   * performing exercises in the wrong (or sub-optimal) sequence

In this chapter, we will try to show you how to avoid these problems, and
others, and present some of the most effective methods for realizing all
the benefits of stretching.

Section: 4.1  Warming Up
========================

Stretching is *not* warming up! It is, however, a very important part of
warming up. Warming up is quite literally the process of "warming up"
(i.e., raising your core body temperature). A proper warm-up should raise
your body temperature by one or two degrees Celsius (1.4 to 2.8 degrees
Fahrenheit) and is divided into three phases:

  1. general warm-up

  2. stretching

  3. sport-specific activity

It is very important that you perform the general warm-up *before* you
stretch. It is *not* a good idea to attempt to stretch before your muscles
are warm (something which the general warm-up accomplishes).

Warming up can do more than just loosen stiff muscles; when done properly,
it can actually improve performance. On the other hand, an improper
warm-up, or no warm-up at all, can greatly increase your risk of injury
from engaging in athletic activities.

It is important to note that active stretches and isometric stretches
should *not* be part of your warm-up because they are often
counterproductive.  The goals of the warm-up are (according to Kurz): "an
increased awareness, improved coordination, improved elasticity and
contractibility of muscles, and a greater efficiency of the respiratory and
cardiovascular systems." Active stretches and isometric stretches do not
help achieve these goals because they are likely to cause the stretched
muscles to be too tired to properly perform the athletic activity for which
you are preparing your body.

Section: 4.1.1  General Warm-Up
-------------------------------

The general warm-up is divided into two parts:

  1. joint rotations

  2. aerobic activity

These two activities should be performed in the order specified above.

Section: 4.1.1.1  Joint Rotations
.................................

The general warm-up should begin with joint-rotations, starting either from
your toes and working your way up, or from your fingers and working your
way down. This facilitates joint motion by lubricating the entire joint
with synovial fluid. Such lubrication permits your joints to function more
easily when called upon to participate in your athletic activity. You
should perform slow circular movements, both clockwise and
counter-clockwise, until the joint seems to move smoothly.  You should
rotate the following (in the order given, or in the reverse order):

  1. fingers and knuckles

  2. wrists

  3. elbows

  4. shoulders

  5. neck

  6. trunk/waist

  7. hips

  8. legs

  9. knees

 10. ankles

 11. toes

Section: 4.1.1.2  Aerobic Activity
..................................

After you have performed the joint rotations, you should engage in at least
five minutes of aerobic activity such as jogging, jumping rope, or any
other activity that will cause a similar increase in your cardiovascular
output (i.e., get your blood pumping).  The purpose of this is to raise
your core body temperature and get your blood flowing.  Increased blood
flow in the muscles improves muscle performance and flexibility and reduces
the likelihood of injury.

Section: 4.1.2  Warm-Up Stretching
----------------------------------

The stretching phase of your warmup should consist of two parts:

  1. static stretching

  2. dynamic stretching

It is important that static stretches be performed *before* any dynamic
stretches in your warm-up.  Dynamic stretching can often result in
overstretching, which damages the muscles (see Section 4.12.3
[Overstretching]).  Performing static stretches first will help reduce this
risk of injury.

Section: 4.1.2.1  Static Warm-Up Stretching
...........................................

Once the general warm-up has been completed, the muscles are warmer and
more elastic. Immediately following your general warm-up, you should engage
in some slow, relaxed, static stretching (see Section 3.5 [Static
Stretching]).  You should start with your back, followed by your upper body
and lower body, stretching your muscles in the following order (see Section
4.8 [Exercise Order]):

  1. back

  2. sides (external obliques)

  3. neck

  4. forearms and wrists

  5. triceps

  6. chest

  7. buttocks

  8. groin (adductors)

  9. thighs (quadriceps and abductors)

 10. calves

 11. shins

 12. hamstrings

 13. instep

Some good static stretches for these various muscles may be found in most
books about stretching.  See Section Appendix A [References on Stretching].
Unfortunately, not everyone has the time to stretch all these muscles
before a workout. If you are one such person, you should at least take the
time to stretch all the muscles that will be heavily used during your
workout.

Section: 4.1.2.2  Dynamic Warm-Up Stretching
............................................

Once you have performed your static stretches, you should engage in some
light dynamic stretching: leg-raises, and arm-swings in all directions (see
Section 3.2 [Dynamic Stretching]). According to Kurz, you should do "as
many sets as it takes to reach your maximum range of motion in any given
direction", but do not work your muscles to the point of fatigue. Remember
- this is just a warm-up, the real workout comes later.

Some people are surprised to find that dynamic stretching has a place in
the warm-up. But think about it: you are "warming up" for a workout that is
(usually) going to involve a lot of dynamic activity. It makes sense that
you should perform some dynamic exercises to increase your dynamic
flexibility.

Section: 4.1.3  Sport-Specific Activity
---------------------------------------

The last part of your warm-up should be devoted to performing movements
that are a "watered-down" version of the movements that you will be
performing during your athletic activity.  `HFLTA' says that the last phase
of a warm-up should consist of the same movements that will be used during
the athletic event but at a reduced intensity. Such "sport-specific
activity" is beneficial because it improves coordination, balance,
strength, and response time, and may reduce the risk of injury.

Section: 4.2  Cooling Down
==========================

Stretching is *not* a legitimate means of cooling down. It is only part of
the process.  After you have completed your workout, the best way to reduce
muscle fatigue and soreness (caused by the production of lactic acid from
your maximal or near-maximal muscle exertion) is to perform a light
"warm-down". This warm-down is similar to the second half of your warm-up
(but in the reverse order). The warm-down consists of two phases:

  1. sport-specific activity

  2. dynamic stretching

  3. static stretching

Ideally, you should start your warm-down with about 10-20 minutes of
sport-specific activity (perhaps only a little more intense than in your
warm-up). In reality however, you may not always have 10-20 minutes to
spare at the end of your workout. You should, however, attempt to perform
at least 5 minutes of sport-specific activity in this case.  The
sport-specific activity should immediately be followed by stretching:
First perform some light dynamic stretches until your heart rate slows down
to its normal rate, then perform some static stretches.  Sport-specific
activity, followed by stretching, can reduce cramping, tightening, and
soreness in fatigued muscles and will make you feel better.

According to `HFLTA', "light warm-down exercise immediately following
maximal exertion is a better way of clearing lactic acid from the blood
than complete rest."  Furthermore, if you are still sore the next day, a
light warm-up or warm-down is a good way to reduce lingering muscle
tightness and soreness even when not performed immediately after a workout.
See Section 4.12 [Pain and Discomfort].

Section: 4.3  Massage
=====================

Many people are unaware of the beneficial role that massage can play in
both strength training and flexibility training. Massaging a muscle, or
group of muscles, immediately prior to performing stretching or strength
exercises for those muscles, has some of the following benefits:

increased blood flow
     The massaging of the muscles helps to warm-up those muscles,
     increasing their blood flow and improving their circulation.

relaxation of the massaged muscles
     The massaged muscles are more relaxed. This is particularly helpful
     when you are about to stretch those muscles. It can also help relieve
     painful muscle cramps.

removal of metabolic waste
     The massaging action, and the improved circulation and blood flow
     which results, helps to remove waste products, such as lactic acid,
     from the muscles. This is useful for relieving post-exercise soreness.

Because of these benefits, you may wish to make massage a regular part of
your stretching program: immediately before each stretch you perform,
massage the muscles you are about to stretch.

Section: 4.4  Elements of a Good Stretch
========================================

According to `SynerStretch', there are three factors to consider when
determining the effectiveness of a particular stretching exercise:

  1. isolation

  2. leverage

  3. risk

Section: 4.4.1  Isolation
-------------------------

Ideally, a particular stretch should work only the muscles you are trying
to stretch. Isolating the muscles worked by a given stretch means that you
do not have to worry about having to overcome the resistance offered by
more than one group of muscles. In general, the fewer muscles you try to
stretch at once, the better.  For example, you are better off trying to
stretch one hamstring at a time than both hamstrings at once.  By isolating
the muscle you are stretching, you experience resistance from fewer muscle
groups, which gives you greater control over the stretch and allows you to
more easily change its intensity.  As it turns out, the splits is not one
of the best stretching exercises. Not only does it stretch several
different muscle groups all at once, it also stretches them in both legs at
once.

Section: 4.4.2  Leverage
------------------------

Having leverage during a stretch means having sufficient control over how
intense the stretch becomes, and how fast.  If you have good leverage, not
only are you better able to achieve the desired intensity of the stretch,
but you do not need to apply as much force to your outstretched limb in
order to effectively increase the intensity of the stretch. This gives you
greater control.

According to `SynerStretch', the best stretches (those which are most
effective) provide the greatest mechanical advantage over the stretched
muscle. By using good leverage, it becomes easier to overcome the
resistance of inflexible muscles (the same is true of isolation).  Many
stretching exercises (good and bad) can be made easier and more effective
simply by adjusting them to provide greater leverage.

Section: 4.4.3  Risk
--------------------

Although a stretch may be very effective in terms of providing the athlete
with ample leverage and isolation, the potential risk of injury from
performing the stretch must be taken into consideration.  Once again,
`SynerStretch' says it best: Even an exercise offering great leverage and
great isolation may still be a poor choice to perform. Some exercises can
simply cause too much stress to the joints (which may result in injury).
They may involve rotations that strain tendons or ligaments, or put
pressure on the disks of the back, or contain some other twist or turn that
may cause injury to seemingly unrelated parts of the body.

Section: 4.5  Some Risky Stretches
==================================

The following stretches (many of which are commonly performed) are
considered risky (M. Alter uses the term `X'-rated) due to the fact that
they have a very high risk of injury for the athlete that performs them.
This does not mean that these stretches should never be performed. However,
great care should be used when attempting any of these stretches. Unless
you are an advanced athlete or are being coached by a qualified instructor
(such as a certified Yoga instructor, physical therapist, or professional
trainer), you can probably do without them (or find alternative stretching
exercises to perform).  When performed correctly with the aid of an
instructor however, some of these stretches can be quite beneficial.  Each
of these stretches is illustrated in detail in the section `X-Rated
Exercises' of M. Alter:

"the yoga plough"
     In this exercise, you lie down on your back and then try to sweep your
     legs up and over, trying to touch your knees to your ears. This
     position places excessive stress on the lower back, and on the discs
     of the spine. Not to mention the fact that it compresses the lungs and
     heart, and makes it very difficult to breathe. This particular
     exercise also stretches a region that is frequently flexed as a result
     of improper posture. This stretch is a prime example of an exercise
     that is very easy to do incorrectly. However, with proper instruction
     and attention to body position and alignment, this stretch can be
     performed successfully with a minimal amount of risk and can actually
     improve spinal health and mobility.

"the traditional backbend"
     In this exercise, your back is maximally arched with the soles of your
     feet and the palms of your hands both flat on the floor, and your neck
     tilted back. This position squeezes (compresses) the spinal discs and
     pinches nerve fibers in your back.

"the traditional hurdler's stretch"
     This exercise has you sit on the ground with one leg straight in front
     of you, and with the other leg fully flexed (bent) behind you, as you
     lean back and stretch the quadricep of the flexed leg. The two legged
     version of this stretch is even worse for you, and involves fully
     bending both legs behind you on either side. The reason this stretch is
     harmful is that it stretches the medial ligaments of the knee
     (remember, stretching ligaments and tendons is *bad*) and crushes the
     meniscus. It can also result in slipping of the knee cap from being
     twisted and compressed.

"straight-legged toe touches"
     In this stretch, your legs are straight (either together or spread
     apart) and your back is bent over while you attempt to touch your toes
     or the floor. If you do not have the ability to support much of your
     weight with your hands when performing this exercise, your knees are
     likely to hyperextend. This position can also place a great deal of
     pressure on the vertebrae of the lower lumbar. Furthermore, if you
     choose to have your legs spread apart, it places more stress on the
     knees, which can sometimes result in permanent deformity.

"torso twists"
     Performing sudden, intense twists of the torso, especially with
     weights, while in an upright (erect) position can tear tissue (by
     exceeding the momentum absorbing capacity of the stretched tissues)
     and can strain the ligaments of the knee.

"inverted stretches"
     This is any stretch where you "hang upside down". Staying inverted for
     too long increases your blood pressure and may even rupture blood
     vessels (particularly in the eyes). Inverted positions are especially
     discouraged for anyone with spinal problems.

Section: 4.6  Duration, Counting, and Repetition
================================================

One thing many people seem to disagree about is how long to hold a passive
stretch in its position. Various sources seem to suggest that they should
be held for as little as 10 seconds to as long as a full minute (or even
several minutes). The truth is that no one really seems to know for sure.
According to `HFLTA' there exists some controversy over how long a stretch
should be held. Many researchers recommend 30-60 seconds. For the
hamstrings, research suggests that 15 seconds may be sufficient, but it is
not yet known whether 15 seconds is sufficient for any other muscle group.

A good common ground seems to be about 20 seconds. Children, and people
whose bones are still growing, do not need to hold a passive stretch this
long (and, in fact, Kurz strongly discourages it).  Holding the stretch for
about 7-10 seconds should be sufficient for this younger group of people.

A number of people like to count (either out loud or to themselves) while
they stretch. While counting during a stretch is not, by itself,
particularly important ... what is important is the setting of a definite
goal for each stretching exercise performed. Counting during a stretch
helps many people achieve this goal.

Many sources also suggest that passive stretches should be performed in
sets of 2-5 repetitions with a 15-30 second rest in between each stretch.

Section: 4.7  Breathing During Stretching
=========================================

Proper breathing control is important for a successful stretch. Proper
breathing helps to relax the body, increases blood flow throughout the
body, and helps to mechanically remove lactic acid and other by-products of
exercise.

You should be taking slow, relaxed breaths when you stretch, trying to
exhale as the muscle is stretching. Some even recommend increasing the
intensity of the stretch only while exhaling, holding the stretch in its
current position at all other times (this doesn't apply to isometric
stretching).

The proper way to breathe is to inhale slowly through the nose, expanding
the abdomen (not the chest); hold the breath a moment; then exhale slowly
through the nose or mouth.  Inhaling through the nose has several purposes
including cleaning the air and insuring proper temperature and humidity for
oxygen transfer into the lungs. The breath should be natural and the
diaphragm and abdomen should remain soft.  There should be no force of the
breath. Some experts seem to prefer exhaling through the nose (as opposed
to through the mouth) saying that exhaling through the mouth causes
depression on the heart and that problems will ensue over the long term.

The rate of breathing should be controlled through the use of the glottis
in the back of the throat.  This produces a very soft "hm-m-m-mn" sound
inside the throat as opposed to a sniffing sound in the nasal sinuses.  The
exhalation should be controlled in a similar manner, but if you are
exhaling through the mouth, it should be with more of an "ah-h-h-h-h"
sound, like a sigh of relief.

As you breathe in, the diaphragm presses downward on the internal organs
and their associated blood vessels, squeezing the blood out of them.  As
you exhale, the abdomen, its organs and muscles, and their blood vessels
flood with new blood.  This rhythmic contraction and expansion of the
abdominal blood vessels is partially responsible for the circulation of
blood in the body.  Also, the rhythmic pumping action helps to remove waste
products from the muscles in the torso.  This pumping action is referred to
as the "respiratory pump".  The respiratory pump is important during
stretching because increased blood flow to the stretched muscles improves
their elasticity, and increases the rate at which lactic acid is purged
from them.

Section: 4.8  Exercise Order
============================

Many people are unaware of the fact that the order in which you perform
your stretching exercises is important.  Quite often, when we perform a
particular stretch, it actually stretches more than one group of muscles:
the muscles that the stretch is primarily intended for, and other
supporting muscles that are also stretched but which do not receive the
"brunt" of the stretch.  These supporting muscles usually function as
synergists for the muscles being stretched (see Section 1.4 [Cooperating
Muscle Groups]).  This is the basis behind a principle that `SynerStretch'
calls the "interdependency of muscle groups".

Before performing a stretch intended for a particular muscle, but which
actually stretches several muscles, you should first stretch each of that
muscle's synergists.  The benefit of this is that you are able to better
stretch the primary muscles by not allowing the supporting muscles the
opportunity to be a limiting factor in how "good" a stretch you can attain
for a particular exercise.

Ideally, it is best to perform a stretch that isolates a particular muscle
group, but this is not always possible.  According to `SynerStretch': "by
organizing the exercises within a stretching routine according to the
principle of interdependency of muscle groups, you minimize the effort
required to perform the routine, and maximize the effectiveness of the
individual exercises."  This is what `Health For Life' (in all of their
publications) calls "synergism": "combining elements to create a whole that
is greater than the mere sum of its parts."

For example, a stretch intended primarily for the hamstrings may also make
some demands upon the calves and buttocks (and even the lower back) but
mostly, it stretches the hamstrings. In this case, it would be beneficial
to stretch the lower back, buttocks, and calves first (in that order, using
stretches intended primarily for those muscles) before they need to be used
in a stretch that is intended primarily for the hamstrings.

As a general rule, you should usually do the following when putting
together a stretching routine:

   * stretch your back (upper and lower) first

   * stretch your sides after stretching your back

   * stretch your buttocks before stretching your groin or your hamstrings

   * stretch your calves before stretching your hamstrings

   * stretch your shins before stretching your quadriceps (if you do shin
     stretches)

   * stretch your arms before stretching your chest

Section: 4.9  When to Stretch
=============================

The best time to stretch is when your muscles are warmed up. If they are
not already warm before you wish to stretch, then you need to warm them up
yourself, usually by performing some type of brief aerobic activity (see
Section 4.1.1 [General Warm-Up]). Obviously, stretching is an important
part of warming-up before (see Section 4.1 [Warming Up]), and cooling-down
after a workout (see Section 4.2 [Cooling Down]). If the weather is very
cold, or if you are feeling very stiff, then you need to take extra care to
warm-up before you stretch in order to reduce the risk of injuring yourself.

Many of us have our own internal body-clock, or "circadian rhythm" as, it
is more formally called: Some of us are "early morning people" while others
consider themselves to be "late-nighters".  Being aware of your circadian
rhythm should help you decide when it is best for you to stretch (or
perform any other type of activity).  Gummerson says that most people are
more flexible in the afternoon than in the morning, peaking from about
2:30pm-4pm.  Also, according to `HFLTA', evidence seems to suggest that,
during any given day, strength and flexibility are at their peak in the
late afternoon or early evening. If this is correct then it would seem to
indicate that, all else being equal, you may be better off performing your
workout right after work rather than before work.

Section: 4.9.1  Early-Morning Stretching
----------------------------------------

On the other hand, according to Kurz, "if you need [or want] to perform
movements requiring considerable flexibility with [little or] no warm-up,
you ought to make early morning stretching a part of your routine." In
order to do this properly, you need to first perform a general warm-up (see
Section 4.1.1 [General Warm-Up]). You should then begin your early morning
stretching by first performing some static stretches, followed by some
light dynamic stretches.  Basically, your early morning stretching regimen
should be almost identical to a complete warm-up (see Section 4.1 [Warming
Up]). The only difference is that you may wish to omit any sport-specific
activity (see Section 4.1.3 [Sport-Specific Activity]), although it may be
beneficial to perform it *if* you have time.

Section: 4.10  Stretching With a Partner
========================================

When done properly, stretches performed with the assistance of a partner
can be more effective than stretches performed without a partner. This is
especially  true of isometric stretches (see Section 3.6 [Isometric
Stretching]) and PNF stretches (see Section 3.7 [PNF Stretching]).  The
problem with using a partner, however, is that the partner does not feel
what you feel, and thus cannot respond as quickly to any discomfort that
might prompt you to immediately reduce the intensity (or some other aspect)
of the stretch.  This can greatly increase your risk of injury while
performing a particular exercise.

If you do choose to stretch with a partner, make sure that it is someone
you trust to pay close attention to you while you stretch, and to act
appropriately when you signal that you are feeling pain or discomfort.

Section: 4.11  Stretching to Increase Flexibility
=================================================

When stretching for the purpose of increasing overall flexibility, a
stretching routine should accomplish, at the very least, two goals:

  1. To train your stretch receptors to become accustomed to greater muscle
     length (see Section 1.6.1 [Proprioceptors]).

  2. To reduce the resistance of connective tissues to muscle elongation
     (see Section 2.2.1 [How Connective Tissue Affects Flexibility]).

If you are attempting to increase active flexibility (see Section 2.1
[Types of Flexibility]), you will also want to strengthen the muscles
responsible for holding the stretched limbs in their extended positions.

Before composing a particular stretching routine, you must first decide
which types of flexibility you wish to increase (see Section 2.1 [Types of
Flexibility]), and which stretching methods are best for achieving them
(see Section 3 [Types of Stretching]).  The best way to increase dynamic
flexibility is by performing dynamic stretches, supplemented with static
stretches.  The best way to increase active flexibility is by performing
active stretches, supplemented with static stretches.  The fastest and most
effective way currently known to increase passive flexibility is by
performing PNF stretches (see Section 3.7 [PNF Stretching]).

If you are very serious about increasing overall flexibility, then I
recommend religiously adhering to the following guidelines:

   * Perform early-morning stretching everyday (see Section 4.9.1
     [Early-Morning Stretching]).

   * Warm-up properly before any and all athletic activities. Make sure to
     give yourself ample time to perform the complete warm-up. See Section
     4.1 [Warming Up].

   * Cool-down properly after any and all athletic activities. See Section
     4.2 [Cooling Down].

   * Always make sure your muscles are warmed-up before you stretch!

   * Perform PNF stretching every other day, and static stretching on the
     off days (if you are overzealous, you can try static stretching every
     day, in addition to PNF stretching every other day).

Overall, you should expect to increase flexibility *gradually*.  However,
If you really commit to doing the above, you should (according to
`SynerStretch') achieve maximal upper-body flexibility within one month and
maximal lower-body flexibility within two months. If you are older or more
inflexible than most people, it will take longer than this.

Don't try to increase flexibility too quickly by forcing yourself.  Stretch
no further than the muscles will go *without pain*.  See Section 4.12.3
[Overstretching].

Section: 4.12  Pain and Discomfort
==================================

If you are experiencing pain or discomfort before, during, or after
stretching or athletic activity, then you need to try to identify the
cause. Severe pain (particularly in the joints, ligaments, or tendons)
usually indicates a serious injury of some sort, and you may need to
discontinue stretching and/or exercising until you have sufficiently
recovered.

Section: 4.12.1  Common Causes of Muscular Soreness
---------------------------------------------------

If you are experiencing soreness, stiffness, or some other form of muscular
pain, then it may be due to one or more of the following:

torn tissue
     Overstretching and engaging in athletic activities without a proper
     warm-up can cause microscopic tearing of muscle fibers or connective
     tissues. If the tear is not too severe, the pain will usually not
     appear until one or two days after the activity that caused the
     damage. If the pain occurs during or immediately after the activity,
     then it may indicate a more serious tear (which may require medical
     attention). If the pain is not too severe, then light, careful static
     stretching of the injured area is supposedly okay to perform (see
     Section 3.5 [Static Stretching]).  It is hypothesized that torn fibers
     heal at a shortened length, thus decreasing flexibility in the injured
     muscles. Very light stretching of the injured muscles helps reduce
     loss of flexibility resulting from the injury. Intense stretching of
     any kind, however, may only make matters worse.

metabolic accumulation
     Overexertion and/or intense muscular activity will fatigue the muscles
     and cause them to accumulate lactic acid and other waste products. If
     this is the cause of your pain, then static stretching (see Section
     3.5 [Static Stretching]), isometric stretching (see Section 3.6
     [Isometric Stretching]), or a good warm-up (see Section 4.1 [Warming
     Up]) or cool-down (see Section 4.2 [Cooling Down]) will help alleviate
     some of the soreness.  See Section 2.3.1 [Why Bodybuilders Should
     Stretch]. Massaging the sore muscles may also help relieve the pain
     (see Section 4.3 [Massage]). It has also been claimed that supplements
     of vitamin C will help alleviate this type of pain, but controlled
     tests using placebos have been unable to lend credibility to this
     hypothesis. The ingestion of sodium bicarbonate (baking soda) before
     athletic activity has been shown to help increase the body's buffering
     capacity and reduce the output of lactic acid. However, it can also
     cause urgent diarrhea.

muscle spasms
     Exercising above a certain threshold can cause a decreased flow of
     blood to the active muscles. This can cause pain resulting in a
     protective reflex which contracts the muscle isotonically (see Section
     1.5 [Types of Muscle Contractions]). The reflex contraction causes
     further decreases in blood flow, which causes more reflex contractions,
     and so on, causing the muscle to spasm by repeatedly contracting.  One
     common example of this is a painful muscle cramp. Immediate static
     stretching of the cramped muscle can be helpful in relieving this type
     of pain. However, it can sometimes make things worse by activating the
     stretch reflex (see Section 1.6.2 [The Stretch Reflex]), which may
     cause further muscle contractions. Massaging the cramped muscle (and
     trying to relax it) may prove more useful than stretching in relieving
     this type of pain (see Section 4.3 [Massage]).

Section: 4.12.2  Stretching with Pain
-------------------------------------

If you are already experiencing some type of pain or discomfort before you
begin stretching, then it is very important that you determine the cause of
your pain (see Section 4.12.1 [Common Causes of Muscular Soreness]).  Once
you have determined the cause of the pain, you are in a better position to
decide whether or not you should attempt to stretch the affected area.

Also, according to M. Alter, it is important to remember that some amount
of soreness will almost always be experienced by individuals that have not
stretched or exercised much in the last few months (this is the price you
pay for being inactive). However, well-trained and conditioned athletes who
work-out at elevated levels of intensity or difficulty can also become
sore. You should cease exercising immediately if you feel or hear anything
tearing or popping.  Remember the acronym "RICE" when caring for an injured
body part.  RICE stands for:  Rest, Ice, Compression, Elevation. This will
help to minimize the pain and swelling. You should then seek appropriate
professional medical advice.

Section: 4.12.3  Overstretching
-------------------------------

If you stretch properly, you should *not* be sore the day after you have
stretched. If you are, then it may be an indication that you are
overstretching and that you need to go easier on your muscles by reducing
the intensity of some (or all) of the stretches you perform.
Overstretching will simply increase the time it takes for you to gain
greater flexibility. This is because it takes time for the damaged muscles
to repair themselves, and to offer you the same flexibility as before they
were injured.

One of the easiest ways to "overstretch" is to stretch "cold" (without any
warm-up). A "maximal cold stretch" is not necessarily a desirable thing.
Just because a muscle can be moved to its limit without warming up doesn't
mean it is ready for the strain that a workout will place on it.

Obviously, during a stretch (even when you stretch properly) you are going
to feel some amount of discomfort.  The difficulty is being able to discern
when it is too much.  In her book, `Stretch and Strengthen', Judy Alter
describes what she calls "ouch! pain": If you feel like saying "ouch!" (or
perhaps something even more explicit) then you should ease up immediately
and discontinue the stretch. You should definitely feel the tension in your
muscle, and perhaps even light, gradual "pins and needles", but if it
becomes sudden, sharp, or uncomfortable, then you are overdoing it and are
probably tearing some muscle tissue (or worse).  In some cases, you may
follow all of these guidelines when you stretch, feeling that you are not
in any "real" pain, but still be sore the next day.  If this is the case,
then you will need to become accustomed to stretching with less discomfort
(you might be one of those "stretching masochists" that take great pleasure
in the pain that comes from stretching).

Quite frequently, the progression of sensations you feel as you reach the
extreme ranges of a stretch are: localized warmth of the stretched muscles,
followed by a burning (or spasm-like) sensation, followed by sharp pain (or
"ouch!" pain). The localized warming will usually occur at the origin, or
point of insertion, of the stretched muscles. When you begin to feel this,
it is your first clue that you may need to "back off" and reduce the
intensity of the stretch. If you ignore (or do not feel) the warming
sensation, and you proceed to the point where you feel a definite burning
sensation in the stretched muscles, then you should ease up immediately and
discontinue the stretch! You may not be sore yet, but you probably will be
the following day. If your stretch gets to the point where you feel sharp
pain, it is quite likely that the stretch has already resulted in tissue
damage which may cause immediate pain and soreness that persists for
several days.

Section: 4.13  Performing Splits
================================

A lot of people seem to desire the ability to perform splits.  If you are
one such person, you should first ask yourself why you want to be able to
perform the splits.  If the answer is "So I can kick high!" or something
along those lines, then being able to "do" the splits may not be as much
help as you think it might be in achieving your goal. Doing a full split
looks impressive, and a lot of people seem to use it as a benchmark of
flexibility, but it will not, in and of itself, enable you to kick high.
Kicking high requires dynamic flexibility (and, to some extent, active
flexibility) whereas the splits requires passive flexibility. You need to
discern what type of flexibility will help to achieve your goal (see
Section 2.1 [Types of Flexibility]), and then perform the types of
stretching exercises that will help you achieve that specific type of
flexibility.  See Section 3 [Types of Stretching].

If your goal really is "to be able to perform splits" (or to achieve
maximal lower-body static-passive flexibility), and assuming that you
already have the required range of motion in the hip joints to even do the
splits (most people in reasonably good health without any hip problems do),
you will need to be patient.  Everyone is built differently and so the
amount of time it will take to achieve splits will be different for
different people (although `SynerStretch' suggests that it should take
about two months of regular PNF stretching for most people to achieve their
maximum split potential).  The amount of time it takes will depend on your
previous flexibility and body makeup.  Anyone will see improvements in
flexibility within weeks with consistent, frequent, and proper stretching.
Trust your own body, take it gently, and stretch often.  Try not to dwell
on the splits, concentrate more on the stretch.  Also, physiological
differences in body mechanics may not allow you to be very flexible.  If
so, take that into consideration when working out.

A stretching routine tailored to the purpose of achieving the ability to
perform splits may be found at the end of this document.  See Section
Appendix B [Working Toward the Splits].

Section: 4.13.1  Common Problems When Performing Splits
-------------------------------------------------------

First of all, there are two kinds of splits: front and side (the side split
is often called a "chinese split"). In a Front split, you have one leg
stretched out to the front and the other leg stretched out to the back. In
a side split, both legs are stretched out to your side.

A common problem encountered during a side split is pain in the hip joints.
Usually, the reason for this is that the split is being performed
improperly (you may need to tilt your pelvis forward).

Another common problem encountered during splits (both front and side) is
pain in the knees. This pain can often (but not always) be alleviated by
performing a slightly different variation of the split. See Section 4.13.2
[The Front Split]. See Section 4.13.3 [The Side Split].

Section: 4.13.2  The Front Split
--------------------------------

For front splits, the front leg should be straight and its kneecap should
be facing the ceiling, or sky. The front foot can be pointed or flexed
(there will be a greater stretch in the front hamstring if the front foot
is flexed). The kneecap of the back leg should either be facing the floor
(which puts more of a stretch on the quadriceps and psoas muscles), or out
to the side (which puts more of a stretch on the inner-thigh (groin)
muscles). If it is facing the floor, then it will probably be pretty hard
to flex the back foot, since its instep should be on the floor. If the back
kneecap is facing the side, then your back foot should be stretched out
(not flexed) with its toes pointed to reduce undue stress upon the knee.
Even with the toes of the back foot pointed, you may still feel that there
is to much stress on your back knee (in which case you should make it face
the floo