School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, UK.
Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, UK.
J Electromyogr Kinesiol. 2023 Oct;72:102806. doi: 10.1016/j.jelekin.2023.102806. Epub 2023 Aug 2.
There is currently equivocal evidence regarding sex-related differences in measures of muscle force and torque control. To that end, we investigated sex differences in knee extensor muscle torque control, using both magnitude- and complexity-based measures, across contraction intensities typical of activities of daily living. 50 participants (25 male, median age [and interquartile range] 23.0 [20.0-33.0]; 25 female, median age [and interquartile range] 21.0 [20.0-40.5]) performed a series of intermittent isometric knee extensor contractions at 10, 20 and 40% maximal voluntary contraction (MVC). Torque was measured in N·m and torque control was quantified according to the magnitude (standard deviation [SD], coefficient of variation [CV]) and complexity (approximate entropy [ApEn], detrended fluctuation analysis [DFA] α) of torque fluctuations. Males exhibited a significantly greater absolute magnitude (i.e., SD) of knee extensor torque fluctuations during contractions at 10% (P = 0.011), 20% (P = 0.002) and 40% MVC (P = 0.003), though no sex differences were evident when fluctuations were normalised to mean torque output (i.e., CV). Males exhibited significantly lower ApEn during contractions at 10% (P = 0.002) and 20% MVC (P = 0.024) and significantly greater DFA α during contractions at 10% (P = 0.003) and 20% MVC (P = 0.001). These data suggest sex differences in muscle torque control strategies and highlight the need to consider both the magnitude and complexity of torque fluctuations when examining sex differences in muscle force control.
目前，关于肌肉力量和扭矩控制的性别差异存在矛盾的证据。为此，我们使用基于幅度和复杂度的测量方法，研究了不同性别在日常生活活动中典型收缩强度下的膝关节伸肌扭矩控制的性别差异。50 名参与者（25 名男性，中位数[和四分位数范围]23.0[20.0-33.0]；25 名女性，中位数[和四分位数范围]21.0[20.0-40.5]）在 10%、20%和 40%最大自主收缩（MVC）下进行了一系列间歇性等长膝关节伸肌收缩。以 N·m 测量扭矩，并根据扭矩波动的幅度（标准差[SD]、变异系数[CV]）和复杂度（近似熵[ApEn]、去趋势波动分析[DFA]α）来量化扭矩控制。男性在 10%（P=0.011）、20%（P=0.002）和 40%MVC（P=0.003）的收缩时，膝关节伸肌扭矩波动的绝对幅度（即 SD）明显更大，但当波动归一化为平均扭矩输出（即 CV）时，没有显示出性别差异。男性在 10%（P=0.002）和 20% MVC（P=0.024）的收缩时的 ApEn 明显更低，在 10%（P=0.003）和 20% MVC（P=0.001）的收缩时的 DFAα明显更高。这些数据表明，肌肉扭矩控制策略存在性别差异，并强调在研究肌肉力量控制的性别差异时，需要同时考虑扭矩波动的幅度和复杂度。
