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 I 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/s 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/s. There was no statistically significant difference for 60 and 180 degrees/s 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/s 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/s for the empty can (P>.05). Internal-rotation values at 60 and 180 degrees/s decreased for both peak torque and total work for all groups. External-rotation peak torque and total work at 60 degrees/s increased for group I. External-rotation peak torque and total work at 180 degrees/s 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.