Abstract
Abstract Although the determinant impact of exercise-induced muscle fatigue prior to postural balance assessment has been widely described, recent evidence suggests that hyperventilation and sensorimotor losses, rather than muscle fatigue, are responsible for the changes observed in postural balance. However, the association between localized muscle fatigue (LMF), induced by isokinetic dynamometer protocol test and assessed through surface electromyography, and postural balance in adults is poorly understood. We aimed to evaluate the association between the LMF of the rectus femoris and static postural balance in 51 adult men (43±14.8 years; 26.9±5 kg/m2). We obtained physical activity level and postural balance, respectively, through a triaxial accelerometry and a force platform. The quadriceps femoris strength and endurance were obtained using an isokinetic dynamometer and surface electromyography simultaneously. The association between the isokinetic and electromyographic LMF and static postural balance was investigated using linear regression models adjusted for age, body mass index, and isokinetic quadriceps strength and LMF. The correlations between postural balance variables and isokinetic muscle strength and LMF were weak-to-moderate. After multivariate analyses, we observed that electromyographic LMF were a predictor of postural balance, mainly of the mean amplitude and COP area and velocity in the mediolateral direction, regardless of isokinetic variables. Therefore, LMF plays a determinant role in the postural balance of physically active adult men. Fatigue indices are significant predictors of postural balance, regardless of previous fatigue induction.
Highlights
Localized muscle fatigue (LMF) is defined as an exercise-induced reduction in the ability of a muscle to generate force or power, regardless of the ability to sustain the task[1,2]
We found significant positive correlations between electromyographic LMF with mean amplitude in mediolateral direction and center of pressure (COP) area and velocity in ST with eyes closed
We investigated the association between electromyographic LMF of the rectus femoris and static postural balance in physically active adult men
Summary
Localized muscle fatigue (LMF) is defined as an exercise-induced reduction in the ability of a muscle to generate force or power, regardless of the ability to sustain the task[1,2]. Unlike muscle strength[4], the association between LMF and postural balance in adults is poorly understood. Acute induction of muscle fatigue by specific protocols of high-intensity exercises negatively affects the postural balance in both adults and older adults[5,6]. Recent evidence suggests that hyperventilation rather than muscle fatigue is responsible for changes in postural balance during the induction of fatigue by intense short-term exercise[7]. Even in exercises with different intensities that induce different levels of hyperventilation, postural balance impairment was identified[7,8]. Considering that other physiological mechanisms can influence postural balance after fatigue induction protocols, it is essential to investigate the extent to which LMF determine the postural balance in adults
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