Hammami, M, Gaamouri, N, Aloui, G, Shephard, RJ, and Chelly, MS. Effects of combined plyometric and short sprint with change-of-direction training on athletic performance of male U15 handball players. J Strength Cond Res 33(3): 662-675, 2019-This study examined the effects of combined plyometric and change-of-direction training (CPT) on selected measures of performance (repeated-sprint T-test [RSTT], sprint performance [5, 10, 20, and 30 m], change-of-direction tests [modified Illinois test and T-half test], squat jump, countermovement jump, countermovement jump with aimed arms 5-jump test, Y-balance test, Stork balance test, and 20-m shuttle run) in male U15 handball players. Players were randomly divided between experimental (n = 14; age: 14.5 ± 0.3 years) and control (n = 14; age: 14.6 ± 0.2 years) groups. All trial participants trained and played matches together, but for 8 weeks in the latter part of the season, the experimental group replaced the tactical part of their normal regimen by a biweekly course of CPT. This induced significant increases in sprint performance relative to controls (p = 0.006, effect size [ES] = 0.135, 8.7%; p=<0.001, ES = 0.214, 7.4%; p = 0.022, ES = 0.096, 7.2%; and p = 0.032, ES = 0.085, 8.9% over distances of 5, 10, 20, and 30 m, respectively). The modified Illinois test and T-half test also showed significant gains for experimental subjects (p < 0.025; ES = 0.205, 4.2% and p < 0.001; ES = 0.093, 5.3%, respectively), as did vertical and horizontal jumps. However, there were no significant changes of RSTT, 20-m shuttle run, or balance. Nevertheless, we conclude that the current CPT is effective in enhancing sprint performance, change-of-direction tests, and vertical and horizontal jumping and thus it can be commended to male U15 handball players as a useful option for improving important components of their physical performance.