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Swapan Mookerjee
06-07-2004, 02:59 AM
This is in response to Dr. Hinrichs query about gastrocnemius muscle
activity during the "Sit & Reach" movement. We completed an EMG analysis
of the Sit & Reach" test (regular, modified) and found the gastroc
activity was close to Erector Spinae and Gluteus Maximus EMG response.
Ankle positioning has been reported to affect range of motion at the
hip. This includes lower extremity flexibility tests, such as the
sit-and-reach, and modified sit-and-reach tests (Boland and Adams, 2000;
Gajdosik, LeVeau, and Bohannon, 1985; Liemohn, Martin, and Pariser,
1997). We have also meaured plantar pressures at the foot during the
sit and reach test and found interesting patterns related to the degree
of ankle flexibility (between subjects and also between the feet in an
individual subject).
Hope this helps.
Sincerely,


Swapan Mookerjee, PhD
Professor, Exercise Science
Bloomsburg University
139 Centennial Hall
Bloomsburg, PA 17815

>>> Richard Hinrichs 6/6/2004 7:26:52 PM >>>

Dear fellow biomechanists,

It has been sometime since I have posted a question or comment on this
forum although I still read what the rest of you are writing each day.
The following question comes from observation of my own muscles during
stretching exercises and my own knowledge of anatomy (or perhaps lack
thereof):

Why do I feel discomfort in my gastrocnemius muscles when I attempt a
"sit and reach" (hamstrings) stretch with my ankles in a neutral
position vs. when I do the same stretch with my ankles slightly planter
flexed (no gastrocs discomfort)? This implies that my gastrocs are
being stretched differently between the two versions of this exercise.
The only joints changing their position during the actual stretching
exercises are my hips (flexing). I keep my knees fully extended either
way and my ankles fixed in one of two positions. As far as I know the
gastrocs are not supposed to change their length at all by changes in
hip position, only knee and ankle. Is there some connective tissue link
between the stretch of the hamstrings and the stretch in the gastrocs
not predicted by the simple 2 joint models of these muscles?

Thanks in advance for your thoughts on this matter.

Regards,

--Rick

Richard N. Hinrichs, Ph.D.
Dept. of Kinesiology
Arizona State University
P.O. Box 870404
Tempe, AZ 85287-0404
(1) 480-965-1624 (phone)
(1) 480-965-8108 (fax)
hinrichs@asu.edu (email)
www.public.asu.edu/~hinrichs/ (personal web page)
www.asu.edu/clas/kines/ (Dept. web page)

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