EFFECT OF FATIGUE ON EXPLOSIVE STRENGTH AND MUSCLE ARCHITECTURE OF THE VASTUS LATERALIS

ABSTRACT Introduction: There has been little research on changes in rate of torque development (RTD) and muscle architecture. This study evaluated the effect fatigue RTD architecture vastus lateralis (VL). Methods: Seventeen volunteers (25.5 ± 6.2 years; 177.2 12.9 cm; 76.4 13.1 kg) underwent isokinetic knee extension assessment at 30°/s to obtain peak (PT-ISK), before after a set intermittent maximal voluntary isometric contractions (MVIC) (15 reps – 3 s contraction, rest) used promote fatigue, monitored by median frequency (MDF) electromyography from VL, rectus femoris medialis muscles. Before protocol, ultrasound images VL were obtained measure thickness (MT), fascicle length (FL), angle (FA). The (PT-ISM) RTDs 50 ms windows calculated for each MVIC. reported as absolute values normalized PT-ISM. Results: Fatigue was confirmed due significant reductions MDF all three After PT-ISK reduced 239.0±47.91 177.3±34.96 Nm, PT-MVIC 269.5±45.63 220.49±46.94 Nm. All presented change protocol. However, did not demonstrate any differences. No differences found VL. Conclusions: reduction explosive strength occurred concomitantly with maximum strength, evidenced lack TDT. Level Evidence III.