Benitez Brian, Kwak Minyoung, Succi Pasquale J, Mitchinson Clara J, Bergstrom Haley C
Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40536, USA.
Muscles. 2024 Dec 4;3(4):417-430. doi: 10.3390/muscles3040035.
Surface mechanomyographic (sMMG) signals have been used to examine sex-specific differences in the mechanical behavior of muscle during fatiguing exercise. However, studies often utilize simple amplitude- and frequency-based analyses, which only reveal the static components of the sMMG signal.
Thus, a wavelet-based analysis was used to examine changes in the spectral intensity of the non-dominant limb's vastus lateralis during a fatiguing, maximal, unilateral isometric leg extension in recreationally active men ( = 11) and women ( = 10). Relative changes in spectral intensities and instantaneous mean frequency (IMF) were examined using linear mixed-effect models. Time-to-task failure was compared using an independent sample -test.
The neuromuscular responses demonstrated parallel decreases in IMF ( < 0.001). Further, there were parallel, nonlinear, decreases in spectral intensity across wavelets ( < 0.001) and there were no sex differences in time-to-task failure ( = 0.15).
These data showed no sex-specific differences in exercise fatigability or muscle mechanics during fatiguing exercise of the leg extensors. However, when collapsed across sex, wavelet-specific changes in spectral intensity over time reveal novel insights into the interplay between low- and high-frequency components during fatigue.
表面肌机械图（sMMG）信号已被用于研究疲劳运动期间肌肉机械行为的性别差异。然而，以往研究通常采用基于简单幅度和频率的分析方法，这些方法仅揭示了sMMG信号的静态成分。
因此，本研究采用基于小波的分析方法，对11名男性（ ）和10名女性（ ）在进行疲劳性、最大强度的单侧等长伸腿运动时，非优势侧股外侧肌的频谱强度变化进行了研究。使用线性混合效应模型对频谱强度和瞬时平均频率（IMF）的相对变化进行了分析。使用独立样本 -检验对任务失败时间进行了比较。
神经肌肉反应显示IMF平行下降（ < 0.001）。此外，各小波的频谱强度呈平行、非线性下降（ < 0.001），且任务失败时间无性别差异（ = 0.15）。
这些数据表明，在腿部伸肌的疲劳运动中，运动疲劳性或肌肉力学方面不存在性别特异性差异。然而，当按性别合并数据时，随着时间推移，频谱强度的小波特异性变化揭示了疲劳期间低频和高频成分之间相互作用的新见解。
