Abstract
Strength is an important factor in athletic performance. Although maximal strength is readily measurable using isokinetic dynamometry other parameters are needed to assess the specific explosive component of muscular strength. To identify these parameters, 41 high-level long-distance runners (17 female and 24 male) and 65 high-level sprinters (22 female and 43 male) performed maximal isokinetic knee flexion/extension exertions at 60°/s and 300°/s using the dominant limb. Multiple strength parameters of hamstrings and quadriceps were studied including peak torque (PT) at both velocities, %PT at 0.2 s of contraction initiation at 60°/s, average explosive work at 300°/s, average power at 300°/s, average power at 300°/s divided by the PT at 60°/s (Relative Power Index – RPI), and average power at 300°/s divided by the PT at 300°/s. The only parameter which did not significantly correlate with (PT60) was the RPI in both flexion and extension. Irrespective of gender, this parameter was also significantly higher in sprinters compared with long-distance runners, and higher in the hamstrings than in the quadriceps. Therefore the use of this parameter is recommended for measuring explosive strength related to sprinting performance in the athlete. Reference data for the RPI in high-level sprinters are provided.