UPPER EXTREMITY AND LOWER EXTREMITY MUSCLE FATIGUE FOLLOWING A PITCHING PERFORMANCE

Abstract

Pitching fatigue is associated with the development of poor mechanics that may predispose an athlete to injury. PURPOSE: The purpose of this study was to examine muscle fatigue during a pitching performance. METHODS 13 baseball pitchers from four universities and one independent minor league team were tested pre and post 19 games. Pitchers threw an average of 98±29 pitches through 7.0±1.6 innings. Upper extremity strength (shoulder flexion, abduction, adduction, scaption, internal rotation, external rotation and scapular stabilizers) and lower extremity strength (hip flexion, abduction, adduction and extension) were assessed using a hand-held dynamometer. Fatigue was assessed by a side (dom Vs. non-dom) by fatigue (pre Vs. post game) ANOVA. RESULTS Strength tests prior to pitching revealed that the pitching arm was 12.4% weaker (p = 0.004) in scaption and 9.9% (p = 0.013) stronger in internal rotation compared to the contralateral side. Post-game strength tests revealed 14.8% strength loss in shoulder flexion (p = 0.001), 18.3% strength loss in internal rotation (p = 0.01), and 13.3% strength loss in shoulder adduction (p = 0.006). Lower extremity tests also revealed a bilateral hip abduction strength loss of 8.2% (p = 0.038). CONCLUSION: Since the pitching arm was stronger in internal rotation at baseline and subsequently experienced the greatest fatigue, the performance demand appeared to be greatest for the internal rotators. Previously, EMG analyses suggest that the supraspinatus muscle is highly active during the pitching motion. However, weakness in baseline scaption strength of the pitching arm, combined with minimal scaption fatigue following the pitching performance is not consistent with the supraspinatus muscle being highly active during the pitching motion.