The effects of jump-rope training on shoulder isokinetic strength in adolescent volleyball players.

OBJECTIVE To investigate the effect of a 12-wk weighted-jump-rope training program on shoulder strength. DESIGN Pretest to posttest experimental design. SETTING University sports physiotherapy laboratory. PARTICIPANTS 24 healthy volleyball players age 13-16 y. INTERVENTION Group 1 took weighted-rope training (n = 9), group 2 took unweighted-rope training (n = 8), and group 3 did not train with any specific program (n = 7). MAIN OUTCOME MEASURES Players' strength determined with an isokinetic dynamometer (Isomed 2000) at 180 and 60 degrees on external and internal rotators, supraspinatus peak torque, and total work of the dominant shoulder. Kruskal-Wallis and Mann-Whitney U tests were used to determine the difference among the groups. RESULTS At pretraining evaluation, there were no significant differences in the test scores of the isokinetic test of full can and empty can between the groups at 60 and 180 degrees. There was no statistically significant difference for 60 and 180 degrees between pretraining and posttraining assessment (P > .05) except that total eccentric work increased in groups 1 and 3 but decreased in group 2 at 180 degrees during the full can (P < .05). There was no significant difference among the groups between the pretraining and posttraining testing at both 180 and 60 degrees for the empty can (P > .05). Internal-rotation values at 60 and 180 degrees decreased for both peak torque and total work for all groups. External-rotation peak torque and total work at 60 degrees increased for group 1. External-rotation peak torque and total work at 180 degrees increased for all groups. CONCLUSIONS The results indicate that a jump-rope training program is a good conditioning method for overhead athletes because of its potential benefits to shoulder strength.