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Hello, biomechanics community:
I am curious to know if anyone has conducted or run across any research
that can somehow approximate the in-vivo failure strength of ligaments
and/or tendons. It could be through some computer simulations, a series
of functional strength tests, etc. To give some more perspective on the
application of this knowledge:
As some of you may know, we study a lot of baseball players,
particularly baseball pitchers. We measure things like elbow varus
torque, shoulder proximal force, and shoulder horizontal adduction
torque. We currently measure these values, but have no real reference
as to what that individual is capable of withstanding. For instance,
two pitchers are tested; pitcher A has 100 Nm of maximum elbow varus
torque and pitcher B has 80 Nm of varus torque. The default assumption
is that pitcher A is stressing his elbow more than pitcher B. However,
if we were somehow able to determine that pitcher A had a threshold of
150 Nm while pitcher B had a threshold of 85 Nm, then it is clear that
pitcher B (94% of max) is actually stressing his elbow a lot more than
pitcher A (67% of max).
Our missing link is determining these threshold values. While we
obviously cannot go around snapping live people's arms to determine
failure strength, perhaps there is some way to estimate it. Off the top
of my head, the solution may be something akin to the sub-maximal VO2
test in exercise physiology or the manual muscle test in EMG
applications.
Any thoughts or ideas on this subject are much appreciated.
Thank you.
Dave Fortenbaugh, M.S.
Biomechanist
American Sports Medicine Institute
833 St. Vincent's Drive Suite 100
Birmingham, AL 35205
I am curious to know if anyone has conducted or run across any research
that can somehow approximate the in-vivo failure strength of ligaments
and/or tendons. It could be through some computer simulations, a series
of functional strength tests, etc. To give some more perspective on the
application of this knowledge:
As some of you may know, we study a lot of baseball players,
particularly baseball pitchers. We measure things like elbow varus
torque, shoulder proximal force, and shoulder horizontal adduction
torque. We currently measure these values, but have no real reference
as to what that individual is capable of withstanding. For instance,
two pitchers are tested; pitcher A has 100 Nm of maximum elbow varus
torque and pitcher B has 80 Nm of varus torque. The default assumption
is that pitcher A is stressing his elbow more than pitcher B. However,
if we were somehow able to determine that pitcher A had a threshold of
150 Nm while pitcher B had a threshold of 85 Nm, then it is clear that
pitcher B (94% of max) is actually stressing his elbow a lot more than
pitcher A (67% of max).
Our missing link is determining these threshold values. While we
obviously cannot go around snapping live people's arms to determine
failure strength, perhaps there is some way to estimate it. Off the top
of my head, the solution may be something akin to the sub-maximal VO2
test in exercise physiology or the manual muscle test in EMG
applications.
Any thoughts or ideas on this subject are much appreciated.
Thank you.
Dave Fortenbaugh, M.S.
Biomechanist
American Sports Medicine Institute
833 St. Vincent's Drive Suite 100
Birmingham, AL 35205