The objective of this study was to investigate the effect of obesity on markers of neuromuscular fatigability of ankle muscles and their potential relationships with postural control capacities. Two groups: non-obese control group (CG; n = 15; age = 40.1 ± 13.9 years; BMI = 23.9 ± 2.8 kg/m2) and obese group (OG; n = 15; age = 44.2 ± 12.4 years; BMI = 42.2 ± 5.2 kg/m2), performed two postural tasks with and without vision in order to collect parameters of center of pressure (CoP) displacements; area (cm2), velocity (mm/s), length (cm) and the ratio length/area. Fatigability was estimated during 60 repeated maximal voluntary contractions of plantar (PF) and dorsal flexors (DF). The maximal force, critical force (Fcr) presenting the asymptote of the force-time evolution and rate of the force decrease (τ) were extracted. Results reported that CoP parameters were higher in OG compared to CG in all postural tasks (p < 0.05). Fcr of PF and DF were 39% and 28% lower respectively in OG compared to CG (p < 0.05). Only τ of PF was 12% lower in OG (p < 0.05). Fcr of PF was negatively correlated with the ratio length/area in OG in all postural tasks (r = 0.86 and r = 0.85, respectively, p < 0.05). We concluded that obesity is associated with a decreased Fcr of ankle muscles expressing the intensity threshold above which fatigue develops drastically. We also revealed that decreased fatigability threshold particularly that of PF, could partly explain postural control alterations in obese adults.

中文翻译：

---

肥胖成年人下肢易疲劳性阈值与姿势控制之间的关系。

这项研究的目的是调查肥胖对踝部肌肉神经肌肉易疲劳性标志物的影响及其与姿势控制能力的潜在关系。两组：非肥胖对照组（CG; n = 15;年龄= 40.1±13.9岁; BMI = 23.9±2.8 kg / m2）和肥胖组（OG; n = 15;年龄= 44.2±12.4岁; BMI = 42.2±5.2 kg / m2），在有和没有视力的情况下执行两个姿势任务，以收集压力中心（CoP）位移的参数；面积（cm2），速度（mm / s），长度（cm）和长度/面积比。在60次重复进行的足底（PF）和背屈（DF）的最大自愿收缩过程中，估计了可疲劳性。提取最大力，临界力（Fcr）（表示力-时间演化的渐近线）和力减小率（τ）。结果报告，在所有姿势任务中，OG中的CoP参数均高于CG（p <0.05）。与CG相比，OG中PF和DF的Fcr分别降低39％和28％（p <0.05）。OG中只有PF的τ低12％（p <0.05）。在所有姿势任务中，PF的Fcr与OG的长度/面积之比呈负相关（r = 0.86和r = 0.85，分别为p <0.05）。我们得出的结论是，肥胖与脚踝肌肉Fcr降低相关，表达强度阈值，疲劳强度大大超过该阈值。我们还发现，降低易疲劳性阈值，尤其是PF的易疲劳性阈值，可以部分解释肥胖成年人的姿势控制改变。OG中只有PF的τ低12％（p <0.05）。在所有姿势任务中，PF的Fcr与OG的长度/面积之比呈负相关（分别为r = 0.86和r = 0.85，p <0.05）。我们得出的结论是，肥胖与脚踝肌肉Fcr降低相关，表达强度阈值，疲劳强度大大超过该阈值。我们还发现，降低易疲劳性阈值，尤其是PF的易疲劳性阈值，可以部分解释肥胖成年人的姿势控制改变。OG中只有PF的τ低12％（p <0.05）。在所有姿势任务中，PF的Fcr与OG的长度/面积之比呈负相关（r = 0.86和r = 0.85，分别为p <0.05）。我们得出的结论是，肥胖与脚踝肌肉Fcr降低相关，表达强度阈值，疲劳强度大大超过该阈值。我们还发现，降低易疲劳性阈值，尤其是PF的易疲劳性阈值，可以部分解释肥胖成年人的姿势控制改变。