2022 Volume 67 Pages 91-102
This study aimed to investigate differences in the isometric rate of force development (IRFD) for the early, late, and whole phases of the force-time curve during explosive leg extension among ball sports athletes and track and field athletes. Ninety-one athletes specializing in different ball sports (ball sports athletes group), 43 sprinters and jumpers (sprinters & jumpers group), 10 throwers (thrower group) and 14 endurance runners (endurance runners group) performed the isometric unilateral leg press with explosive force production. A custombuilt dynamometer was used to measure IRFDs during the isometric unilateral leg press with a knee angle of 115 deg. IRFDs for early phase (Early IRFD), late phase (Late IRFD) and overall force-time curve (Average IRFD) were obtained. relative IRFD that took individual body weight (IRFD/BW) were also derived. Differences in IRFDs among the various sport groups were analyzed by one-way ANOVA and multiple comparison. It was found that IRFDs other than Late IRFD/BW showed a significant main effect among the athlete groups (p < 0.05). The results suggested that the characteristics of IRFDs other than Late IRFD/BW might differ among athletes according to their specialization. For multiple comparison, the ball sports athletes group and the sprinters & jumpers group tended to show similar mean IRFD values. However, only mean values for the Early IRFD/BW of sprinters & jumpers group were significantly greater than those for the ball sports athletes group (p < 0.05). In the throwers group, the mean of any IRFD tended to be greater, and the mean values of Early IRFD, Late IRFD, and Average IRFD were significantly greater than in the other groups (p < 0.05). In contrast, the endurance runners group tended to show small mean values for any IRFDs. These present results suggest that the capacity for explosive force production is reflected in the differences of IRFDs other than the Late IRFD/BW among various sports.
