Effect of repeated spike motion on acromiohumeral distance, shoulder ROM, and scapular alignment

Abstract

The purpose of this study was to examine the changes in acromiohumeral distance (AHD), range of motion (ROM) of the shoulder joint, and scapular alignment caused by repeated spike motion. 10 collegiate male volleyball players who participated in this study. Spike motion repeated 50 times. AHD, internal rotation and horizontal flexion in shoulder joint and scapular alignment were measured before and after the volleyball spike task. There was no significant difference of AHD between before and after the task. However, after the task, the 2nd internal rotation and horizontal flexion range of the shoulder joint significantly decreased on the dominant compared to the non-dominant. Also, after the task, the scapula significantly showed upward rotation at 45° abduction and depression at neutral position in shoulder joint. It was suggested that 50 repetitions of the spike motion may cause posterior shoulder tightness (PST) and altered scapula alignment, but it did not decrease AHD. The results of this study were immediate changes after 50 repetitions of the spike motion, so it is necessary to examine the changes over time in the future.