Introduction: The Paralympic Games have gained a lot of popularity in recent years. In wheelchair basketball, the shoulder joint is the most commonly used joint. This sport includes a series of overhead repetitive movements such as shooting, passing, rebounding, forward and backward movement of the wheelchair, and circling. Frequent may affect the balance and strength of the muscles in the shoulder joint. Performing repetitive movements during sports activities and especially performing throwing movements above the head puts the shoulder joint under frequent pressure and tension, as a result, it may lead to the occurrence of strength asymmetry and disturb the stability of the shoulder. Some studies have introduced the asymmetry of glenohumeral joint muscle strength in the dominant and non-dominant limb as a risk factor for injury in athletes in disciplines with overhead movements. Also, isokinetic evaluation has been introduced as a gold standard to check the existence of muscle asymmetry between organs.
Research method: 10 elite wheelchair basketball players participated in this study. The present research was of a descriptive and comparative type that compared the isokinetic strength of the shoulder and elbow joint of the dominant and non-dominant side of elite wheelchair basketball players at speeds of 60 and 180 degrees per second during a testing session. In order to evaluate the strength of internal and external rotator muscles of the shoulder, extensors and flexors of the elbow, the isokinetic device System Biodex 4 was used. 6 maximal contractions, concentric-concentric, were taken from each person. Statistical analysis of data was done using Spss version 27 software. The normality of the parameters was measured by the Shapiro-Wilk test and the independent t-test was used to compare the isokinetic strength at a significance level of α ≥ 0.05.
Findings: The results of the independent t-test of elite wheelchair basketball players showed that there is a significant difference in the maximum torque factors of the shoulder internal and external rotator muscles, elbow extensors and flexors at two speeds of 60 and 180 degrees per second on the dominant and non-dominant side of the upper limb. There is none (P<0.05).
Conclusion: The results show that there is no difference in the isokinetic strength of the upper limb of the dominant and non-dominant side of elite wheelchair basketball players, and this indicates a high level of muscle strength balance in the upper limb of both dominant and non-dominant sides. Wheelchair basketball is basically a bi-lateral sport, and in most of the activities of this field, especially driving a wheelchair and shooting, both hands are involved and under pressure at the same time, so the muscles of the non-dominant limb can also be affected and be associated with an increase in muscle strength. .