CHICAGO, Apr 20, 2009 (UPI via COMTEX) -- The "windmill" pitching motion may
explain the high incidence of anterior shoulder pain seen in female softball
players, U.S. researchers said.
"The conventional belief has been that the underhand throwing motion of softball
places little stress on the arm," lead author Dr. Nikhil Verma of the Rush
University Medical Center in Chicago said in a statement. "But that is not the
case."
The study involved seven women -- three collegiate and four professional
pitchers -- who underwent motion analysis and surface electromyography to
evaluate the muscle firing pattern of their biceps in the course of a windmill
pitch. Electromyography detects electrical potential generated by muscle cells
when they contract.
The study, published in the American Journal of Sports Medicine, found that even
though the upper arm movement in both baseball and fast-pitch softball gives the
ball about the same velocity, muscle force during the windmill pitch was much
higher.
Moreover, the maximum force, or maximum contraction, occurred not when the arm
was cocked, as in baseball's overhand pitching, but when the arm circled around
from the 9 o'clock position, almost fully extended back, to the 6 o'clock
position, perpendicular with the ground, completing its windmill motion to
release the ball. Consequently, the biceps, not the elbow, took the majority of
the stress, Verma said.
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Copyright 2009 by United Press International