Long Devon, Dotan Raffy, Pitt Brynlynn, McKinlay Brandon, O'Brien Thomas D, Tokuno Craig, Falk Bareket
1 Brock University.
2 Liverpool John Moores University.
Pediatr Exerc Sci. 2017 Feb;29(1):84-93. doi: 10.1123/pes.2016-0056. Epub 2016 Aug 19.
The electromyographic threshold (EMG) is thought to reflect increased high-threshold/type-II motor-unit (MU) recruitment and was shown higher in boys than in men. Women differ from men in muscular function.
Establish whether females' EMG and girls-women differences are different than males'.
Nineteen women (22.9 ± 3.3yrs) and 20 girls (10.3 ± 1.1yrs) had surface EMG recorded from the right and left vastus lateralis muscles during ramped cycle-ergometry to exhaustion. EMG root-mean-squares were averaged per pedal revolution. EMG was determined as the least residual sum of squares for any two regression-line data divisions, if the trace rose ≥ 3SD above its regression line. EMG was expressed as % final power-output (%Pmax) and %VOpk power (%P).
EMG was detected in 13 (68%) of women, but only 9 (45%) of girls (p < .005) and tended to be higher in the girls (%Pmax= 88.6 ± 7.0 vs. 83.0 ± 6.9%, p = .080; %P= (101.6 ± 17.6 vs. 90.6 ± 7.8%, p = .063). When EMG was undetected it was assumed to occur at 100%Pmax or beyond. Consequently, EMG values turned significantly higher in girls than in women (94.8 ± 7.4 vs. 88.4 ± 9.9%Pmax, p = .026; and 103.2 ± 11.7 vs. 95.2 ± 9.9%P, p = .028).
During progressive exercise, girls appear to rely less on higher-threshold/type-II MUs than do women, suggesting differential muscle activation strategy.
肌电图阈值（EMG）被认为反映了高阈值/II型运动单位（MU）募集的增加，且已表明男孩的该阈值高于男性。女性在肌肉功能方面与男性不同。
确定女性的肌电图以及女孩与女性之间的差异是否与男性不同。
19名女性（22.9±3.3岁）和20名女孩（10.3±1.1岁）在递增负荷的蹬车运动至疲劳过程中，记录左右股外侧肌的表面肌电图。每蹬踏一圈计算肌电图均方根的平均值。如果曲线上升至高于其回归线≥3个标准差，则将肌电图确定为任意两个回归线数据分区的最小残差平方和。肌电图以最终功率输出百分比（%Pmax）和峰值摄氧量功率百分比（%P）表示。
13名（68%）女性检测到肌电图，但只有9名（45%）女孩检测到（p<0.005），且女孩的肌电图倾向于更高（%Pmax=88.6±7.0对83.0±6.9%，p=0.080；%P=101.6±17.6对90.6±7.8%，p=0.063）。当未检测到肌电图时，假定其在100%Pmax或更高时出现。因此，女孩的肌电图值显著高于女性（94.8±7.4对88.4±9.9%Pmax，p=0.026；103.2±11.7对95.2±9.9%P，p=0.028）。
在进行性运动期间，女孩似乎比女性更少依赖高阈值/II型运动单位，提示肌肉激活策略存在差异。
