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

In a walking cycle design, maximizing the upright balance should be considered in addition to the kinematic constraints, energy consumption rate must be considered. The purpose of this study is to find the optimal step length obtained for each person according to the physical features. In this research, in order to minimize energy consumption rate by considering maximum balance two cost function were defined. the fall cost function was designed based on the concept of MOS and balance index. To investigate the upright balance and to reconstruct the movement pattern, Data from normal walking gait of healthy subjects was taken and seven links model was defined. In this study, the optimal step length was obtained for the person with height, weight and gait cycle characteristics. it is shown that for a person of 92kg mass and 1.87 meters height, the best step length in walking would be 0.54 meters. In this study, the kinematic and kinetic characteristics of human motion were identified by the analysis of gait patterns on a treadmill. Through the calculation of the balance index, individuals are helped to find the optimal step length for which the maximum balance is achieved. The results of the study can provide the optimal step length to correct the gait pattern.