|
| |
| Back Strong & Beltless - Part II
Paul Chek
HOW TO BE BACK STRONG AND BELTLESS!
The worst thing someone could do is discontinue the use of a belt cold
turkey! If you have been using a back belt or weight lifting belt for more than
a month, chances are very good that your abdominal recruitment patterns have
been altered. Your TVA and posterior IO are now likely sitting on the couch,
relaxing, while allowing your rectus abdominis and external obliques to act as
the primary stabilizers of the trunk in concert with the erector spinae muscles.
If you have been using a belt for several months or even years, particularly
if you have had or currently experience any low back pain, chances are very good
that you have sensory-motor amnesia of the deep abdominal wall. If you
remove your belt and go back to your normal Herculean performances in the gym or
start packing power tools around the construction site, chances are very good
you will be purchasing a new Mercedes for your doctor or orthopedic surgeon,
real soon!
When you take the belt off and begin working or lifting, your brain will
sequence the muscles as though you were lifting with the belt. When your nervous
system recruits the rectus abdominis and erector spinae at the greater intensity
as learned when wearing the belt (40,44), you are likely to have increased
compression, torsion and/or sheer in one or more segments of your lumbar spine,
but without the hoop tension provided by the belt (42,43).
Additionally, a correlation of my clinical findings among athletes that wear
belts and have experienced hamstring injury is supported by research. Lander et
al. found that while using weight-belts, there was increased EMG activity of the
vastus lateralis and biceps femoris (55). This is logical when considering the
intimate relationship that exists between the biceps femoris and the TVA via the
thoracolumbar fascia system as an integral part of what is called the "deep
longitudinal system" by Gracovetsky (7 p. 243-251, 15 p. 58) (Figure 14).
Figure 14 - The Deep Longitudinal
System
Adopted from Gracovetsky (7 p. 243-251, 8) and Lee (15 p. 58) the Deep
Longitudinal System illustrates the working relationship between the TVA as
a stabilizer of the pelvis (A), the sacrotuberous ligament (B),
the peroneus longus and biceps femoris (C) and the erector spinae
musculature (D). In the late swing phase of gait, dorsiflexion of the
foot in preparation for heel strike generates tension in the peroneus longus.
Vleeming (7) indicates that approximately 18 percent of that force is
transferred into the biceps femoris, which works to tension the
sacrotuberous ligament, stabilizing the sacrum and ilium at heel strike. The
erector spine musculature serve to dissipate kinetic energy through rotary
action on the spinal column prior to reaching the cranium. This mechanism
may explain the high correlation between biceps femoris injury in lifters
using belts and sprinters with TVA dysfunction; theoretically, the biceps
may be working to tension the thoracolumbar fascia system to compensate for
inadequate action of the TVA. |
If the belt user has developed the habit of responding to the exteroception
provided by the belt by pushing the abdominal wall outward (which will inhibit
the TVA), then it is very likely the brain may up-regulate the recruitment of
the biceps femoris in an attempt to stabilize the thoracolumbar fascia.
This can be done by the biceps femoris because of its intimate relationship
with the thoracolumbar fascia via the sacrotuberous ligament. Having treated
numerous biceps femoris injuries in weight lifters and athletes performing in
sports requiring explosive movement, I have witnessed a strong correlation
between sensory-motor dysfunction of the deep abdominal wall, an inability to
stabilize the lumbopelvic region, and biceps femoris injury.
Additionally, a study titled, "The effect of industrial back belts and
breathing technique on trunk and pelvic coordination during a lifting task,"
found that "phase angles" (relationships) between the pelvis and lumbar spine
during the initial phase of lifting tasks were altered among belt users (56).
The researchers concluded "the change in segmental kinematics was similar to
that previously reported for patients with a history of low back pain" (56).
What this means is that if you stop belt use cold turkey, or even forget your
belt one day, not only will your motor sequencing be aberrant, but the
relative timing of joint movements will also be faulty. This is a formula for
disaster!
THE FORMULA FOR FREEDOM FROM BELTS
To begin, you must assess your TVA strength and function as described below
in "Find the Weakness and Kill It!". Once you have achieved the ability to
recruit your deep abdominal wall and you have restored normal lower abdominal
coordination, it is then safe to begin weaning yourself off the belt.
After performing the test procedures described below and correcting any
deficits, start by only wearing your belt with lifts of greater than 80 percent
intensity (8 rep max or heavier). For some of you, this may mean only performing
your warm-up sets without the belt. For those of you that don't normally lift at
higher than 75 percent maximum intensity (12 reps), you may also want to begin
by only performing your warm-up sets without the belt. The next step would be to
take the belt off during your first working set, and so on. After two weeks of
training, while continuing to use the abdominal retraining techniques described
below, remove the belt for all exercises done at an additional 5 percent
intensity, or two reps closer to your maximum. Continue this progression for 4-8
weeks. If your beltess performances match your previous lifts with a belt, you
may safely drop the belt forever.
Note: If you have any pain in the region
of the back from T7-S3, it is very important not to try weaning yourself off
the belt without professional guidance. Consult a qualified physical therapist
that understands strength training or a C.H.E.K Practitioner near you (locate
a C.H.E.K Practitioner).
Pain in any spinal segment between T7 and S3, or anywhere in the lumbopelvic
region, can inhibit the transversus abdominis and pelvic floor musculature,
leaving you susceptible to injury.
Find the Weakness and Kill It!
A chain is only as strong as its weakest link, and your body is no
different. The first step toward developing a belt free body and toward
reestablishing function of your own natural lumbar corset is to test it. Using a
blood pressure cuff, you can test the TVA for proper function (Figure 13). If
your TVA function is normal, you should be able to reduce the pressure in the BP
cuff by 10 mmHg without any movement of your spine, without flexing your hips,
or pressing your shoulders into the floor. You can safely consider that for each
1 mmHg less than 10 mmHg you de-pressurize the cuff, you have a 10 percent loss
of function. For example, if you could only reduce the BP cuff pressure 5 mmHg,
you are probably about 50 percent deficient in TVA function.
Should you find your level of function is less than 100 percent, I strongly
recommend you follow the exercise progressions described in Table I. For those
of you needing to condition for improved neuromuscular isolation of the muscle
as dictated by your test results, the test becomes the exercise. As indicated in
Table I, you should progress until you can de-pressurize the cuff by 10 mmHg for
100 seconds without rest.
TABLE 1
TRANSVERSUS ABDOMINIS CONDITIONING |
| Week |
Exercise |
Rest |
Intensity |
Reps |
Tempo |
Sets |
| 1 |
4 Point |
<1:00 |
|
10 |
10/10 |
1-4 |
| 2 |
BP Cuff |
<1:00 |
-10mmHg |
10 |
10/10 |
2-4 |
| 3 |
BP Cuff |
45 sec. |
-10mmHg |
10 |
10/5 |
2-4 |
| 4 |
BP Cuff |
30 sec. |
-10mmHg |
2-4 |
=/>100s. |
1 |
Some of you, particularly females, may have a hard time getting your TVA to
fire. This is likely to be the case for anyone with a history of back pain,
currently experiencing back pain, or who has given birth to one or more children
(23,57). To jump start the TVA, I use the "4 Point TVA Exercise" demonstrated in
Figure 15 A-B (23). The 4 Point TVA Exercise works very well because when you
are on all four points, gravity is pulling your viscera downward into your
abdominal wall and stretching the deep abdominal wall muscles.
The stretch excites the spindle cells of the muscle, increasing awareness of
the deep abdominal wall in the sensory-motor cortex. This aids in recruiting the
muscle when afflicted with sensory motor amnesia.
Figure 15
The 4 Point TVA Exercise
A) Positioned on your hands and knees with neutral spinal alignment,
inhale deeply. Be sure to use a diaphragmatic breathing pattern. This means that
as you inhale, your umbilicus should move away from your spine and your belly
should relax and expand.
B) To exercise the TVA, as you exhale through pursed lips, draw the
umbilicus toward the spine. Draw the umbilicus as close to your spine as
possible, holding the TVA contraction for 10 seconds. If you need to breathe
during the ten-second contraction, try to hold the umbilicus inward toward the
spine while you do so. Always preface each contraction with a diaphragmatic
breath, repeating the cycle as described here. Ten repetitions, holding each for
10 seconds would constitute one set. Work up to three sets with one minute rest
between them.
Once you have performed the 4 Point TVA Exercise every day for a
week, retest yourself with the BP cuff. While you are working on your deep
abdominal wall, you can also be working on your lower abdominal strength and
coordination.
LOWER ABDOMINAL COORDINATION TESTING
Belt use has been shown to alter the natural recruitment patterns of the
abdominal wall, favoring the rectus abdominis (40), erector spinae (44) and
potentially disrupting recruitment sequences in the legs (39). It is therefore
no surprise that belt users frequently present with aberrant coordination in the
abdominal wall when assessed clinically.
It is very common for belt users to have reduced ability to control sacral
base inclination, or pelvic tilt. This is another common challenge I must
work through with back pain patients. Inability to control sacral base
inclination can cause instability of the sacroiliac joints, particularly during
forward bending activities (58). Clinically, I have found inability to control
sacral base inclination is also commonly related to such spinal pathology as
spondylolistheses, spondylolysis, spinal instability and disc herniation.
To test yourself, lay on your back and place your hands under your spine
(palms down). When your fingertips are just behind your umbilicus (L3), flex
your hips to 90° and keep your knees fully relaxed (see Figure 16). From this
position, roll your pelvis posteriorly until you can feel the spinous process of
your spine pressing on your fingers. Now, while holding the pressure on your
fingers with your spine, begin lowering your feet to the floor, always keeping
the knees fully bent. If you have normal lower abdominal coordination, you
should be able to slowly lower your feet to the floor and bring your legs back
to the point of 90° hip flexion without the pressure of your spinous processes
at the L3 level ever coming off your fingers (23).
Figure 16 - Lower Abdominal
Coordination Testing
If you are unable to hold consistent pressure while lowering and raising the
legs as described, it is very likely that you have facilitated hip flexors
(22,59). A very simple approach to correcting the problem is to stretch your
hip flexors and repeat the test. If your test is now normal, it is an
indication that you should stretch your hip flexors to reestablish normal
recruitment pathways before doing any heavy lifting. If you stretch your hip
flexors and you are still unable to pass the test, then it is likely you
have developed a faulty motor engram (recruitment pattern). Restoration of
normal motor control in the lower abdominal region is complex and beyond the
scope of this article. Those interested in learning how to make this
correction should study references 23 or 60. |
THE WORLD'S GREATEST WEIGHT BELT!
Once you have passed the lower abdominal coordination test and can decompress
the BP cuff for 100 seconds or longer at 10 mmHg less than where the needle
started, it is time to integrate your deep abdominal wall into your general
movement schema and gym exercises.
It is well documented that coordinative patterns of the abdominal wall are task specific (6,12,14,23). For example, one may have normal abdominal wall
function during a squat pattern, but not a push pattern. Additionally, loss of
abdominal wall coordination is easier to prevent than to restore (61). This should give those of you considering use of a weight belt adequate
reason NOT TO!
I recommend trying what I call "the worlds greatest weight belt". It is
simply a piece of kite string. Place the kite string around your waist at the
belly button level. Exhale and draw your belly button in slightly, just enough
to notice that it has moved toward your spine and that you now have more
definition along the oblique line. With the string snug around your belly now,
tie the string in a knot.
As you perform your exercises in the gym, you should always inhale and draw
your umbilicus off the string prior to exerting any force. This teaches the
brain to activate the TVA first. If you are lifting any significant load, you
will cross the stabilization threshold (23), at which time you will go from
segmental to gross stabilization. This will be identified as visually observable
activation of the external oblique and rectus abdominis.
When the load is heavy enough, you will notice that no matter how hard you
try, you cannot keep the string loose around your torso. If you progressively
reduce the weight, you will eventually cross back under the stabilization
threshold, which will be identified by your ability to perform the lift and keep
the string loose.
It is very important to perform enough low intensity lifting to train the
brain to always recruit the deep abdominal wall before recruiting the outer
unit, or outer muscles, which function as gross stabilizers.
To best condition your body, it is important to focus first on learning to
activate the abdominal wall while performing what I call "Primal PatternsTM".
Primal Patterns' are the movement patterns most likely to have been necessary
for our developmental survival as dictated by the selective pressures of nature
(62). The Primal Patterns are:
- Squatting
- Lunging
- Bending
- Pushing
- Pulling
- Twisting
- Gait (walk, run and sprint)
All these patterns, to be true Primal Patterns, must be performed from a
standing position. If this is not possible, then you will need the help of an
exercise or rehabilitation professional, preferably a C.H.E.K Intern, to assist
you in learning how to correctly perform the sequencing and development of the
movements.
For those interested in an educational resource that teaches integration of
the deep abdominal wall while performing many functional exercises, I recommend
"The Gym Instructor Series" (60). This program covers many pushing, pulling and
abdominal exercises as well as showing how to restore normal coordination and
strength to the inner and outer unit muscles of the abdominal wall and back.
Once you have implemented the training techniques described here, you will be
free from training with the belt and have full confidence that your body now
works correctly. If you have any orthopedic problems at all, it would be wise to
consult a C.H.E.K Practitioner or a skilled rehabilitation professional that
understands the science of corrective exercise to aid you in your quest to be
"BACK STRONG AND BELTLESS!"
CONCLUSION
In this article I discussed several legitimate considerations regarding
chronic use of corsets, back belts, and weight lifting belts. Available research
clearly demonstrates that belts are unable to stabilize the spine at a segmental
level, therefore only stabilizing the torso. Gross stabilization, as provided by
belts, may allow you to lift more weight than you could without the belt,
indicating a stabilizer dysfunction within your body. The increased weight being
lifted as afforded to the lifter by the belt will likely serve to traumatize the
spine due to increased levels of compression, torsion and sheer, increasing the
potential for a serious injury.
Caution should be exercised by those using belts to increase "proprioception,"
as a belt is clearly a form of "exteroceptive stimuli". When the belt is
removed, it is likely to have accomplished little in improving proprioception,
leaving the lifter with an increased risk of injury secondary to belt usage. My
clinical treatment of workers and athletes with spine injuries has shown that
chronic use of weight lifting belts and back belts is highly correlated with
sensory-motor amnesia of the deep abdominal. Finally, weaning yourself off a
belt must be done carefully and in concert with evaluation and treatment of any
stabilizer deficit found in the torso.
References:
- Waddell, G. The Back Pain Revolution. New York: Churchill Livingstone,
1998.
- Ironmind Enterprises (catalog)
- Webster, D. The Iron Game. Scotland: John Geddes Printers Irvine, 1976.
- Lovett, R. Lateral Curvature of the Spine and Round Shoulders
Philadelphia: P. Blakiston's Son & Co., 1912.
- Steindler, A. Post-Graduate Lectures on Orthopedic Diagnosis and
Indications Charles C Thomas, 1951.
- Richardson C., Jull G., Hodges P. and Hides J. Therapeutic Exercise For
Spinal Segmental Stabilization In Low Back Pain - Scientific Basis And
Clinical Approach. London, New York, Philidelphia, Sydney, Toronto: Churchill
Livingstone,1999.
- Ed by: Vleeming A., Mooney V., Snijders C.J., Dorman T.A. and Stoeckart R.
Movement, Stability & Low Back Pain - The Essential Role of the Pelivs. New
York, Edinburgh, London, Madrid, Melbourne, San Francisco and Tokyo: Churchill
Livingstone, 1997.
- Gracovetsky, S. The Spinal Engine. Wien, New York: Springer-Verlag, 1988.
- Dart R.A. The Double-Spiral Arangement Of The Voluntary Musculature In The
Human Body. Surgeons' Hall Journal Vol. 10, No. 2. Oct. 1946 - March 1947.
- Hodges P. W., Richardson C.A. Feedforward contraction of transversus
abdominis is not influenced by the direction of arm movement. Exp Brain Res
(1997) 114:362-370.
- Aruin S.A., Latash M.L. Directional specificity of postural muscles in
feed-forward postural reactions during fast voluntary arm movements. Exp Brain
Res (1995) 103:323-332.
- Cresswell A.G., Grundstrom H., Thorstensson A. Observations on
intra-abdominal pressure and patterns of abdominal intra-muscular activity in
man. Acta Physiol Scand 1992, 144, 409-418.
- Hodges P.W., Richardson C.A. Contraction of the Abdominal Muscles
Associated With Movement of the Lower Limb. Physical Therapy. Vol. 77 No. 2
February, 1997.
- Norris C.M. Functional load abdominal training: part 1. Journal Of
Bodywork And Movement Therapies July 1999
- Lee D. The Pelvic Girdle (2nd. Ed.) - An Approach to the Examination and
Treatment of the Lumbo-Pelvic-Hip Region. Edinburgh, London, New York,
Philadelphia, Sydney, Toronto: Churchill Livingstone, 1999.
- Richardson C.A., Jull G.A. Muscle control - pain control. What exercises
would you prescribe? Manual Therapy(1995) 1, 2-10.
- Bogduk N., Towmey L.T. Clinical Anatomy of the Lumbar Spine (2nd.
Ed.).Melbourne, Edinburgh, London, New York and Tokyo: Churchill Livingstone,
1991.
- Wirhed, R. Athletic Ability & the Anatomy of Motion. Wolfe Medical
Publications Ltd., 1984.
- White, A. and Panjabi, M. Clinical Biomechanics of the Spine 2nd. ED. J.B.
Lippincott Co., 1990.
- Cholewicki, J., Juluru, K., McGill, S. Intra-abdominal Pressure Mechanism
for Stabilizing the Lumbar Spine. Journal of Biomechanics 32 (1999) 13-17.
- Bogkuk, N. Clinical Anatomy of the Lumbar Spine and Sacrum 3rd. ED.
Churchill Livingstone, 1999.
- Chek P. Scientific Back Training. (correspondence course) Encinitas, CA: Chek
Institute, 1995.
- Chek P. Scientific Core Conditioning. (correspondence course) Encinitas, CA:
Chek Institute, 1993,1999.
- Chek P. The Outer Unit. Published at www.personaltraining.com.au.
- Ziglar Z. How To Stay Motivated. (tape series) . Carrollton, TX: The Zig
Ziglar Corp.
- Lahad A., Malter A.D., Berg A.O., Deyo R.A. The effectiveness of four
interventions for the prevention of low back pain. JAMA 1994;272:1286-91.
- Majkowski G.R., Jovag B.W., Taylor B.T., Taylor M.S., Allison S.C., Stetts
D.M., Clayton R.L. The Effect of Back Belt Use on Isometric Lifting Force and
Fatigue of the Lumbar Paraspinal Muscles. Spine Vol. 23, No. 19, pp 2104-2109,
1998.
- National Institute for Occupational Safety and Health. Workplace use of
back belts: Review and recommendations. Rockville, MD: Department of Health
and Human Services (National Institute of Occupational Safety and Health)
Publication No. 94-122, 1994
- Mitchell L.V., Lawler F.H., Bowen D., Mote W., Asundi P., Purswell J.
Effectiveness and cost-effectiveness of employer-issued back belts in areas of
high risk for back injury. J Occup Med 1994 Jan;36(1):90-94.
- Thomas J.S., Lavender S.A., Corcos D.M., Andersson G.B. Effect of lifting
belts on trunk muscle activation during a suddenly applied load. Hum Factors
1999 Dec;41(4): 670-6.
- Reyna J.R., Leggett S.H., Kenny K., Holmes B. and Mooney V. The Effect of
Lumbar Belts on Isolated Lumbar Muscle Strength and Dynamic Capacity. Spine
Vol. 20 No. 1 pp 68-73, 1995.
- McGill S.M., Norman R.w., Sharratt M.T. The effect of an abdominal belt on
trunk muscle activity and intra-abdominal pressure during squat lifts.
Ergonomics 1990 Feb;33(2):147-60.
- Hodgson E.A. Occupational back belt use: a literature review. AAOHN J 1996
Sep;44(9): 438-43.
- Ciriello V.M., Snook S.H. The effect of back belts on lumbar muscle
fatigue. Spine 1995 Jun 1;20(11):1271-8; discussion 1278.
- Cholewicki J., Juluru K., Radebold A., Panjabi M.M., Magill S.M. Lumbar
spine stability can be augmented with an abdominal belt and/or increased
intra-abdominal pressure. Eur Spine J 1999;8(5): 388-95.
- Smith E.B., Rasmussen A.A., Lechner D.E., Gossman M.R., Quintana J.B. The
effects of lumbosacral support belts and abdominal muscle strength on
functional lifting ability in healthy women. Spine 1996 Feb 1;21(3):356-66.
- Zatsiorskii V.M., Sazanov V.P. A Waist-Corset For Decreasing The Risk Of
Injury To The Spine When Lifting Weights And Doing Strength Exercises. Teoriya
I Praktika Fizicheskii Kultury 3:15-17, 1987.
- Bourne N.D., Reilly T. Effect of a weightlifting belt on spinal shrinkage.
Br J Sports Med 1991 Dec;25(4): 209-12.
- Lander J.E., Simonton R.L., Giacobbe J.K.F. The effectiveness of
weight-belts during the squat exercise. Medicine and Science In Sports And
Exercise Vol. 22, No. 1 Feb. 1990 pp 117-26.
- Miyamoto K., Iinuma N., Maeda M., Wada E., Shimizu K. Effects of abdominal
belts on intra-abdominal pressure, intra-muscular pressure in the erector
spinae muscles and myoelectrical activities of trunk muscles. Clinical
Biomechanics, Feb. 1999 14(2): 79-87.
- Drechsler A. The Weightlifting Encyclopedia: A Guide To World Class.
Whitestone, New York: Performance A is A Communications, 1998.
- Axelsson P., Johnsson R., Stromqvist B. Effect of lumbar orthosis on
intervertebral mobioity. A roentgen sterophotogrammetric analysis. Spine 1992
Jun;17(6): 678-81.
- Miller R.A., Hardcastle P., Renwick S.E. Lower spinal mobility and
external immobilization in the normal and pathologic condition. Orthop Rev
1992 Jun;21(6):753-7.
- Bauer J.A., Fry A., Carter C. The Use of Lumbar Supporting Weight Belts
While Performing Squats: Erector Spinae Electromyographic Activity.
- Hodges P. Richardson C., Jull G. Evaluation of the relationship between
laboratory and clinical tests of transversus abdominis function. Physiother
Res Int 1996;1(1):30-40.
- Cholewicki J., Juluru K., McGill S. Intra-abdominal pressure mechanism for
stabilizing the lumbar spine. Journal of Biomechanics 32 (1999) 13-17.
- Keith A. Menders Of The Maimed - The Anatomical & Physiological Principles
Underlying The Treatment Of Injuries To Muscles, Nerves, Bones & Joints.
Robert E. Kreiger Publishing Co, 1975.
- Abreu B.C. Physical Disabilities Manual. (pp 137) New York: Raven Press,
1981.
- Fortin J.D. Weight Lifting (Ch. 45, p. 496) In: Watkins R.G., The Spine In
Sports St. Louis: Mosby, 1996.
- Brownstein B., Bronner S. Functional Movement - In Orthopedic And Sports
Physical Therapy New York, London, Edinburgh, Melbourne, San Francisco, Tokyo:
Churchill Livingstone, 1997.
- Gill K.P., Callaghan M.J. The Measurement of Lumbar Proprioception in
Individuals With and Without Back Pain. Spine Vol. 23, No. 3, pp 371-77.
- Steadman's Medical Electronic Dictionary. Baltimore, MD: Williams &
Wilkins, 1996.
- Hanna T. Somatics: Reawakening the Mind's Control of Movement,
Flexibility, and Health. Cambridge, Massachusetts: Perseus Books, 1988.
- Chek P. Corrective and High-performance Exercise Kinesiology Certification
Manual - Level II (four year internship program course manual) Encinitas, CA:
C.H.E.K Institute.
- Lander J.E., Hundley J.R., Somonton R.L. The effectiveness of weight-belts
during multiple repetitions of the squat exercise. Medcine and Science In
Sports and Exercise 1992 May;24(5):603-9.
- McGorry R.W., Hsiang S.M. The effect of industrial back belts and
breathing technique on trunk and pelvic coordination during a lifting task.
Spine 1999 Jun 1;24(11):1124-30.
- Chek P. Equal But not the same: Consideration for Training Females (correspondence course) Encinitas, CA: C.H.E.K Institute.
- DonTigny R.L. Function of the Lumbosacroiliac Complex as a
Self-Compensating Force-Couple with a Variable-Dependent Transverse Axis: A
Theoretical Analysis. Journal of Manual and Manipulative Therapy Vol. 2:3,
87-93.
- Janda V. Muscles, Central Nervous Motor Regulation and Back Pain. (27-41)
In: Korr I.M. (Ed.)The Neurobiologic Mechanisms in Manipulative Therapy. New
York and London: Plenum Press, 1978.
- Chek P. Core Conditioning Volume 1 part 1: The Gym Instructor Series Encinitas, CA: C.H.E.K Institute, 1997.
- Kegel A.H. Progressive Resistance Exercise In The Functional Restoration
Of The Perineal Muscles. American Journal of Obstetrics and Gynecology August,
1948.
- Chek P. Advanced Program Design (Correspondence Course) Encinitas, CA: C.H.E.K
Institute, 1998.
|
| |
|