Alterations in Upper Extremity Motion after Scapular-Muscle Fatigue

Abstract

Objective:To determine the effect of scapular fatigue on shoulder and elbow kinematics and accuracy.Design:Pretest–posttest.Setting:Laboratory.Participants:30 healthy men.Interventions:Subjects performed seated overhead throws into a target before and after a standardized scapular-muscle-fatigue protocol.Main Outcome Measurements:Shoulder and elbow kinematic data were analyzed during throwing. Scapular upward rotation was measured (0°, 45°, and 90° humeral elevation in scaption) with an inclinometer. Throwing accuracy was measured as mean error distance from the target (cm).Results:After fatigue, there was a significant increase in total elbow motion (12 % more in cocking phase,P< .05) and elbow velocity in the follow-through phase (average and maximum into flexion,P< .05). Throwing accuracy decreased 26% after fatigue (P< .05).Conclusions:Scapular-muscle fatigue results in compensatory motions at the elbow that might affect performance and contribute to elbow pathologies.