Single-joint isometric rate of torque development is not related to counter- movement jump performance in soccer players

Abstract

BACKGROUND AND OBJECTIVE: The quadriceps rate of torque development (RTD) is frequently used to evaluate explosive performance, but its functional meaning has been questioned. Thus, the aim of this study was to investigate if isometric quadriceps RTD correlates with multi-joint dynamic performance and if it has greater correlation with dynamic performance than with a single-joint isokinetic test in soccer players. METHODS: Thirty-nine male soccer players (age 21 ± 5 years, body mass 75 ± 7.5 kg, height 179 ± 5 cm) performed five maximal concentric knee extension isokinetic contractions at a velocity of 180 ◦ /s, followed by three maximal voluntary isometric contractions (MVIC) with knee angle of 60 ◦ , and five countermovement jumps (CMJ). The RTD was derived from MIVC over various time intervals (of 0.05, 0.1, 0.2, 0.3 seconds, and peak RTD) and CMJ height was calculated by flight time method. Pearson Product Moment Correlations were used to determine the relationships between variables. RESULTS: Absolute and relative isokinetic PT correlated positively with CMJ height ( p 0.05, r from �0.272 to 0.296). CONCLUSION:These results indicate that single-joint isometric RTDdoes not correlate withdynamic multi-joint performance. Thus, more specific tests in relation to contraction type, velocity and/or movement pattern should be used.