engleski

Optimal Load for Power Output During Vertical Jumping: the Effect of Training Background

PURPOSE: Several authors examined the effect of training status on optimal load for power production during vertical jumping and provided conflicting findings. In the present study we tested the hypothesis that the optimal load for power production during vertical jumping is dependent on the individual's training background. Contrary to all previous studies, we used both the positive and negative loading. METHODS: Ten untrained men (age: 21 ± 5 yrs), 10 strength-trained male athletes (body-builders ; age: 24 ± 3 yrs) and 11 speed-trained male athletes (karate ; age: 21 ± 4 yrs) performed maximal vertical jumps on a force plate with the loads ranging from 0.7, over 1.0, up to 1.3 times subject's body weight (BW). Positive and negative loading was applied with the specially designed pulley system (1). Body-mass normalized mean power output (i.e., W per kg of body mass) was used as a dependent variable. Data were analyzed using two-way (group x load) ANOVA with repeated measures on one (load) factor. Statistical significance was set at P < 0.05. RESULTS: The two-way ANOVA revealed a significant group x load interaction effect (F = 9.4 ; p < 0.001), as well as the significant group (F = 35.7 ; p < 0.001) and load (F = 402.9 ; p < 0.001) effects. Strength- and speed-trained athletes had a significantly higher mean power output compared to untrained individuals at all loading conditions (Figure 1). No significant differences in mean power output were observed between the two groups of athletes. Finally, a significant loading-associated decrease in mean power output was observed for all three groups (Figure 1). CONCLUSION: Strength- and speed-trained athletes produce significantly higher power outputs during vertical jumping at all loading conditions compared to untrained individuals. More importantly, optimal load for maximum power production during vertical jumping appears to be unrelated to the subject’s training background, and is highest during negative loading.

power; muscle function; vertical jump

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