Research in Sport Medicine and Technology

Background and Purpose: Frequent throwing Movements can change its muscular strength and range of motion balance shoulder athletes compared to non-athletes. The purpose of this study was to the comparison of strength ratio between agonist and antagonist muscles and range of motion of the shoulder in volleyball players and non-athletes. Research Method: Thirty female volleyball players (mean age±SD; 21±2.58 year) and thirty non-athletes individuals (mean age ± SD; 22±1.13 years) participated in this study. Manual muscle test (MMT) and Leighton Flexometer was respectively used for measuring the strength and ROM of the participants. Demographic information was collected through questionnaires. After determining the normal data distribution independent and paired samples T-test was used to analyze them. Results: In Compare ratio of agonist to antagonist muscle strength in the dominant and non-dominant hand volleyball players (p≤0.001, p=0.002) As well as dominant hand in both groups (volleyball and control) (p≤0.001, p=0.003) in the ratio of internal to external rotation and abduction to adduction strength was significant difference (P≤0.05). A significant decrease in range of motion in internal rotation and extension movements of the dominant hand (p≤0.001, p=0.005) and a significant increase in external rotation volleyball players in dominant hand was observed (p=0.026).Conclusion: Repeated pattern of movements in the volleyball sports for a long time causes muscle imbalance in strength and range of motion shoulder joint that in case of inadequate attention and lack of proper stretching and strengthening exercises to use, this asymmetry can make athletes prone to injury his performance will decrease