Date of Award
Master of Physical Therapy (MPT)
Movement -- physiology; Wrist Joint
By understanding proper pitching mechanics, therapists can develop better preventative and rehabilitation programs for pitchers. The purpose of this study was to explain the joint motions and muscle activity that occur at the elbow during both an overhand and sidearm baseball pitching delivery. Three healthy adult pitchers with recreational sidearm pitching experience were examined with synchronized high-speed video digitization and surface electromyography (EMG). It was proposed that the increased valgus moment during the acceleration phase due to the sidearm delivery would subsequently show an increase in EMG activity by the wrist flexor-pronator group to provide additional varus torque in minimizing the generated valgus moment.
Results of the study did not indicate an increase in muscle activity of the wrist flexor-pronator group during the acceleration phase of the sidearm throws. However, subject #3 showed altered mechanics during the sidearm throw, and the peak muscle activity was displayed during the cocking phase rather than the deceleration phase. All other throws examined, both overhand and sidearm, resulted in peak muscle activity in the deceleration phase.
Tradition based knowledge passed from one generation to the next speaks of the harmful effects at the elbow with throwing sidearm. However, this study did not support tradition based knowledge, and it showed minimal if any muscle activation patterns which differ from previous literature.
Mack, Cordell J., "An EMG and video analysis of the wrist flexors during a sidearm baseball delivery" (1997). Physical Therapy Scholarly Projects. 294.