The relationship between anaerobic performance,muscle strength and sprint ability in American football players

The purpose of this study was to investigate the relationship between, isokinetic knee strength, anaerobic performance and sprinting ability in American football players. Twenty-eight male amateur American football players participated in this study voluntarily. Knee extension and flexion strengths were evaluated at 60, 150 and 240°/s, anaerobic performance was evaluated by Wingate anaerobic power test and sprint ability was determined by single- (20 m) and repeated-sprint (12 × 20 m) tests. Extension strength was significantly correlated with peak and mean power in all contraction velocities; however the only significant correlation between flexion strength and peak power was indicated at 240°/s. In the case of sprinting ability, there was a significant but weak correlation between 240°.s $^{-1}$ knee flexion strength and percentage of performance decrement from 10–20 m (r=0.381, p< 0.05). No measure of strength was significantly related to single-sprint and other measures of repeated-sprint ability (p> 0.05). Hence, although maximal knee extension strength is a crucial component in anaerobic performance of American football players, lack of its association with single- and repeated-sprint performance indicates that factors other than strength might be involved in single-and repeated-sprint performance in this group of athletes.