Alexander Wakely, J. Jay Dawes, Erika Hernandez, Robert George Lockie

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This study investigated the effects of a 4-week strength and conditioning program on the strength, power, and throwing velocity of male junior varsity and varsity high school athletes. Six junior varsity and eight varsity water polo players were recruited. Pre- and post-testing included isometric grip and leg/back strength; vertical jump (VJ); 2-kg medicine ball throw; and maximum throwing velocity with a water polo ball.  All participants completed a 4-week strength and conditioning program designed to enhance base levels of strength. Data was analyzed via a two-way repeated measures ANOVA (p<0.05), including groups as a between-subjects factor measured at two levels (junior varsity, varsity). The within-subject factor (time) represented pre- and post-training measures. Change scores were calculated for each variable; independent samples t-tests (p<0.05) compared change scores between groups. There were significant time interactions for grip strength, leg/back strength, VJ, and throwing velocity (p≤0.031). Post hoc analyses showed that the junior varsity group significantly improved grip strength, leg/back strength, and VJ (p≤0.019). The varsity group improved grip strength and throwing velocity (p≤0.005). There were no significant time*group interactions (p=0.068-0.156), or significant between-group differences in change scores (p=0.134-0.756). Thus, rate of improvement was not different between groups. Nonetheless, a greater adaptive reserve may have existed in the junior varsity group such that they experienced grip strength, leg/back strength, and VJ improvements after a short-term training program. A longer program may be required for varsity athletes to experience pronounced changes in strength and power. Nevertheless, these adaptations could translate into greater throwing velocity.


adolescent, isometric strength, lower-body power, motor skill, vertical jump

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