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Lynn Curtis(seton Hall Univ.)
04-17-2003, 11:29 PM
Hello, the following are the responses that I receive to my questions regarding
squats. The original question is stated and the responses follow. I did receive
a response from Dr. Sue Ann Sisto who has done extensive work with squats. She
works through Kessler in West Orange. She has done research related to my
question but hasnít calculate all the data to get final outcomes. Her research
looked at self-selected squats and intervention of proper squat techniques. She
also looked at the effects of external rotation of the legs during the squat.
Her email is ssisto@kmrrec.org

Thank you for all responses.
Lynn Curtis
Graduate Student
Seton Hall University


>Hello,
>I am a graduate student at Seton Hall University. I am interested in studying
>forces at the knee joint during a squat. I have found a lot of articles related
>to the forces at the patellofemoral joint and tibiofemoral joint during a
>squat. I am looking for articles that look at the technical aspects of how a
>squat is performed in terms of keeping the knee so that it stays behind the
>tips of the toes during a squat and if that makes any difference on forces at
>the knee. In addition, if anyone knows of different search engines that I might
>use to gather further information on the subject I would appreciate if you let
>me know.
>Lynn Curtis
>Graduate Student
>Seton Hall University.






Actually Lynn, this is exactly the study Dr. Fleisig and myself would like
to do next. You are right, there is no data out there, and I'm very
interested in this topic as well. There is very limited data from B.G.
Ariel entitled "Biomechanical analysis of the knee joint during deep knee
bends with heavy load", published in Biomechanics IV, Vol 1, Nelson &
Morehouse eds, Baltimore: University Park Press, pp 44-52, 1974), in which
Ariel states that "the forward movement of the knees while the subject
performed the squat was associated with the greatest shearing force".
However, this really doesn't explain or define what is meant by a shearing
force, and no statistically comparison between those who had anterior knee
movement beyond the toes and those who did not. Empirically, it seems
shearing forces are greatest (the knees hurt!!) the further the knees move
anterior (e.g., sissy squats done by bodybuilders), but this must be
validated experientially. Sorry I'm not more help. Maybe in the next year
I'll do this study.
Rafael

Rafael Escamilla, Ph.D., P.T., C.S.C.S.

California State University, Sacramento

Department of Physical Therapy

>





Dear Lynn

This is an old article but it may be informative. It gives realistic patellar
tendon forces during a clean and jerk ( which goes into about 90 deg flexion
during the jerk phase. The magnitudes were later confirmed by the work the
Butler/Noyes/Grood did with 1/3 patellar tendon grafts with young doctors.

Zernicke, R. F., Garhammer, J. J. , and Jobe, F. W. Human patellar tendon
rupture: A kinetic analysis. Journal of Bone and Joint Surgery 59A: 179-183,
1977.

Cheers.

Ron Zernicke
University of Calgary



Lynn,

Hereís the article you want:
Escamilla RF, Fleisig GS, Zheng N, Lander JE, Barrentine SW, Andrews, Bergemann
BW, Moorman CT. Effects of technique variations on knee biomechanics during
the squat and leg press. Medicine & Science in Sports & Exercise 33(9) : 1552-
1566,2001.


- Glenn

Glenn S. Fleisig, Ph. D., Smith & Nephew Chair of Research
American Sports Medicine Institute
1313 13th Street South
Birmingham, AL 35205
(email) glennf@asmi.org
(tele) 205-918-2139
(fax) 205-918-0800
(website) www.asmi.org



Lynn,

I would suggest contacting the National Strength & Conditioning Association
(NSCA). Their website is a great resource.

Another resource is your local Athletic Trainers. There is typically a
Strength & Conditioning Specialist on staff in most atheletic training rooms.
Barring that, any Certified Athletic Trainer should be able to answer your
questions.

Gary Christopher
MS, ATC



Lynn,

Refer to Dr. Escamillaís work. He is formerly of Duke University and at CSU,
Sacramento.

MSSE Vol. 33, No. 9 2001 1552-1566
MSSE Vol. 1, No. 1 2001 127-141

These two articles should get you started in the right direction, especially
the first on the list. If you need further assistance, please do not hesitate
to contact me via email.

Good Luck,
Jeff Casebolt

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