890 MEP097 – Which upper extremity plyometric exercises are suitable for improving scapular stabilization in female volleyball players?

AbstractBackground Upper extremity plyometric exercises are used to reduce the risk of injury by maintaining the strength ratio of the muscles that provide scapular stabilization when sports demand high-speed power training such as volleyball. However, which plyometric exercises are more effective in increasing scapular stabilization is not clear.Objective The purpose of this study was to investigate the activity of the scapular muscles during plyometric exercises to guide the exercise selection for improving scapular stabilization in female volleyball players.Design Experimental study.Setting Young elite female volleyball players.Participants Thirty-two female volleyball players(age:17.0±2.2yr, height:175.9±7.3cm, mass:64.2±8.7kg) with at least 5 years of training were included. Main Outcome Measurements Scapular asymmetry was assessed with the lateral scapular slide test. The activations of the scapulothoracic muscles (upper, middle, lower trapezius (UT, MT, LT,and serratus anterior(SA)) during 8 different bilateral upper extremity plyometric exercises were recorded by using wireless surface electromyography. The ratios were calculated by dividing the normalized amplitude of UT by the LT, MT, and SA. Plyometric exercises were classified as 100–80%:moderate, 80%-60%:good, and <%60:excellent based on lower UT/MT,UT/LT, andUT/SA activation.Results Scapular asymmetry was found in 37.5% of the players. Significant differences (p<0.01,power=1.000) and a large effect size (η2=0.254) were found among the scapular muscle activation ratios observed during the plyometric exercises. It was found that supine chest pass and medicine ball throw-to-the-ground exercises showed a lower UT/SA ratio (%32.19 and%38.59) than the plyometric wall and against TOGU push-up exercises (%83.72 and%77,04)(p<0.001)(Figure 1).Conclusion The most appropriate plyometric exercises should be selected to target MT, LT, and SA while inhibiting UT in strength training programs to prevent or manage scapular dyskinesia in overhead athletes.This research showed that supine chest pass and medicine ball throw-to-the-ground exercises displayed excellent (<%60:UT/SA) SA activity levels and might therefore be best suited to the injury prevention program for young female volleyball players.Download figure Open in new tab Download powerpoint Abstract 890 Figure 1 EMG muscle activation ratio of UT/SA for all eight exercises. Exc.1: Overhead Medicine Ball Throw, Exc. 2: Overhead Medicine Ball Throw to the 45° Inclined Platform, Exc. 3: Medicine Ball Throw to the Ground, Exc. 4: Wall Chest Pass Exc.5: Plyometric Wall Push-up Exc. 6: Plyometric Wall Push-up against TOGU Exc. 7: Supine Chest Pass Exc. 8: Upward Chest Pass