To investigate the additional effects of upper extremity plyometric training in recreational overhead athletes with anterior shoulder instability. We hypothesize that compared to strengthening training alone, plyometric training combined with strengthening training will significantly improve strength, proprioception, shoulder kinematic and muscle activity, shoulder pain, and shoulder function.
Subjects aged between 20-40, participating in overhead sports regularly with anterior or multidirectional shoulder instability were randomized into either the plyometric group (plyometric and strengthening training) or the strengthening group (strengthening training only). Both groups will receive a 60-minute supervised, progressive upper-extremity training protocol twice a week for 6 weeks. The primary outcomes include isokinetic assessment of shoulder internal and external rotation with Biodex Multi-Joint System 4 Pro, including concentric and eccentric peak torque and amortization time during the transition from external rotation to internal rotation (calculated by LabView); active and passive shoulder joint position sense (absolute error); functional performance test of the upper extremity (sitting medicine ball throw distance); shoulder pain and instability with visual analogue scale (VAS); the Disability of Arm, Shoulder and Hand (DASH) questionnaire. All the outcomes will be measured at baseline and following 12 sessions of exercise training. The independent T-test will be used to compare the change scores between groups. The significant level was set at 0.05.
20 subjects (mean age 28.6 ± 5.44; male: n=10) were included in the current study. The change score of active joint position sense at 75° external rotation showed significant improvement (p=0.005) in the strengthening group (-0.46 ± 2.06) than the plyometric group (1.71 ± 0.54). There were no findings of significant differences between groups in passive joint position sense, strength, performance, pain or function.
A 6-week upper body strengthening program is as effective as a strengthening plus plyometric training program for overhead athletes with shoulder instability in shoulder strength, performance, pain, and function outcomes, and may have better improvement in active joint position sense around the greater degree of shoulder external rotation in 90-degree abduction.
Strength training with enough intensity and high movement quality might be an effective way to improve shoulder proprioception. However, the potential effects of upper body plyometric training for shoulder instability athletes need to be further investigated.
plyometric training
strengthening exercises
