Abstract:

BACKGROUND: The isokinetic muscle strength test system can quantitatively test the shoulder flexor and extensor muscles and objectively analyze the relationship between size and balance of flexor and extensor. Therefore, it could be used for strength training monitoring as well as prediction and rehabilitation of sports injuries.
OBJECTIVE: To understand shoulder flexor and extensor strength characteristics of adolescent softball players, and find out shortcomings in the shoulder flexor and extensor strength to provide guidance for adolescent athletes’ strength training and point out possible sports injury risks caused by imbalanced strength.
METHODS: ISOMED2000 isokinetic testing system (D&R, Germany) was employed to test the isokinetic strength of shoulder flexor and extensor of 12 adolescent female softball players from Shanghai Sports University, China.
RESULTS AND CONCLUSION: With the increase of test speed, the bilateral shoulder flexor and extensor peak torque, the flexor and extensor average power ratio, and the flexor and extensor powers were reduced, but the flexor and extensor average power was on the rise. Under the same test speed, flexor and extensor peak torque, the flexor and extensor peak torque ratio, the flexor and extensor average power, the flexor and extensor average power ratio and the flexor powers of the throwing shoulder were significantly larger than those of the non-throwing shoulder (P < 0.05), while the extensor peak torque and the extensor average power of the throwing and non-throwing shoulders showed no significant differences (P > 0.05). Under the same test speed, bilateral shoulder homonymous flexor strength ratio was larger than that of the extensor, and the extensor power of the throwing shoulder was less than that of the non-throwing shoulder. The ratio of homolateral shoulder flexor and extensor ranged from 70% to 80%. These results indicate that there is a significant difference between the flexor strength of the bilateral shoulders in adolescent softball players, but the bilateral extensor strength is similar. Flexor fast strength and extensor maximum strength of the throwing shoulder are lower. Besides, the isokinetic muscle strength test system can be used to evaluate the flexor and extensor strength in adolescent softball athletes, based on which coaches can give targeted strength training in adolescent softball athletes.

中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程

Key words: Shoulder Joint, Muscle Strength, Adolescent