Effects of ankle and hip muscle fatigue on postural sway and attentional demands during unipedal stance

Abstract

The effect of muscle fatigue on quiet standing is equivocal, including its duration/recovery and whether it leads to an increase in attentional demands. The purpose of this study was to assess the effects of ankle and hip muscle fatigue on postural sway and simple reaction time during a unipedal task. Two groups of 14 young adults (mean age=22.50±3.23) had to stand on their dominant leg for 30-s trials before and after fatigue of hip or ankle flexors and extensors. Half of the unipedal trials were performed in a dual-task condition where subjects, in addition to standing, had to respond verbally to an auditory stimulus. Sway area, and sway variability and velocity in the AP and ML planes were calculated using center of pressure data obtained from a force platform. Voice reaction time was recorded seated and during the dual-task condition to assess attentional demands. A main effect of fatigue was found for AP sway variability (p=0.027), AP sway velocity (p=0.017) and ML sway velocity (p=0.004). Both groups showed increased sway velocity in both directions and in reaction time during the dual-task condition (p<0.001), but reaction time did not increase with fatigue. A group by fatigue interaction was found significant for ML sway velocity (p=0.043). Results suggest that hip and ankle fatigue affected postural control in the fatigued plane (AP) but only hip fatigue affected postural control in the non-fatigued plane (ML sway velocity). However, fatigue did not lead to an increase in attentional demands and increased AP and ML sway velocity had recovered within 30min.

Influência da distância de corrida na pressão plantar

“…Among the reasons for this result we can highlight a fatigue effect, which was previously suggested as determinant for center of pressure shifts toward the forefoot 14 most likely due to fatigue in intrinsic muscles of the foot and ankle 15 . In addition, an association between running fatigue and magnitude of plantar pressure was suggested after short races with 400 m distance 9 .…”

The effect of hip abductor fatigue on static balance and gait parameters

“…Bisson et al [27] reported a significant improvement in the SD of the anterior-posterior COP excursion only when the hip flexors and extensor muscles were fatigued (p<0.05). Since the hip abductor muscles have an affect on postural control in the coronal plane, it would cause variability in the medio-lateral distance.…”

“…Subjects were measured for static balance and gait parameters prior to and after fatigue induction. The static balance parameters assessed were the distance of COP, including medio-lateral, anterior-posteior, the total distance of the COP, as well as the sway variability of the COP, indicating the standard deviation of the medio-lateral and anterio-posterior distance [27]. The gait parameters assessed were velocity, cadence, step length, stride length, single support time and double support time.…”

Effects of Localized Muscle Fatigue and Whole Body Fatigue on Postural Control during Single-Leg Stance

“…On the other hand, if the muscle around the hip joint experiences fatigue, the opposite situation occurs, which is called the ankle strategy (Bizid et al, 2009;Gribble & Hertel, 2004a). Therefore, single-leg stance is controlled by a combination of the ankle and hip strategies (Bisson, McEwen, Lajoie, & Bilodeau, 2011;Riemann, Myers, & Lephart, 2003). Some have questioned whether COP measurements are valid indicators of postural control (Adlerton et al, 2003;Winter, 1995;Moe-Nilssen, 1998) because changes in the COP trajectory are not always accompanied by corresponding changes in the position of the COM.…”