DATASET FOR STUDY: Acute fatiguing effects and biomechanical characteristics of a single bout eccentric quasi-isometric resistance exercise of ankle plantar flexors

INTRODUCTION: Investigation of the eccentric quasi-isometric (EQI) resistance exercise has started in recent years. However, the biomechanical characteristics and fatigue effects of EQI muscle actions in the ankle plantar flexors remainunexplored. This study aimed to compare the biomechanical characteristics ofplantarflexion EQIs and post-EQI acute fatigue between two different loadingintensities. METHODS: Twenty regularly physically active participants (9 men, 11 women)completed 3 sets comprising of a single EQI muscle contraction at 75% and 90%(one intensity for each leg in a random order) of maximal voluntary isometriccontraction (MVIC) on an isokinetic dynamometer. Outcome variables includedtotal contraction time, torque impulse, angular velocities and range of motionduring EQI muscle actions, as well as pre- and post-contraction MVIC measures.RESULTS: The analysis indicated no statistically significant effect of EQI muscle-action onMVIC torque (main effect of time: p = 0.636). There were also no statisticallysignificant differences between EQI muscle actions performed at 75% and 90%MVIC regarding angular velocity (p = 0.244). However, executing EQI musclecontraction at 75% MVIC resulted in statistically significantly larger totalcontraction time, total torque impulse, and range of motion (p < 0.001)compared to EQI at 90% MVIC. DISCUSSION: These findings suggest that performing EQI contractions at 75% MVIC may be more effective for generating greater mechanical stimulus without inducing significant acute fatigue.