The aim of the study was to investigate the relationships between vastus lateralis muscle fiber length and fiber type composition in individuals with minimal exposure to systematic resistance/power training. In sixty female physical education students (age: 21.03 ± 2.1 years, body weight: 59.8 ± 9.7 kg, body height: 166.2 ± 6.5 cm), with no experience in systematic training, lean body mass, VL muscle architecture and fiber composition type, countermovement jumping (CMJ) performance, and isometric leg press rate of force development were evaluated. Data were analyzed for all participants, as well as two equally numbered groups assigned according to their maximum countermovement jumping power (High-Power or Low-Power group). Significant but low correlations were found between type II muscle fiber percentage and fascicle length (N = 60, p < 0.05). Significant correlations were found between type IIa and IIx muscle fiber percentage cross-sectional area (%CSA) and fascicle length (N = 60; r = 0.321, and r = 0.378; respectively, p < 0.05). These correlations were higher for the High-Power group (r = 0.499, and r = 0.522; respectively, p < 0.05), and lower, and nonsignificant, for the Low-Power group. The best predictor of strength/power performance was the lean body mass of the lower extremities (r = 0.389–0.645, p < 0.05). These results suggest that in females with minimal exposure to systematic training, fascicle length may be weakly linked with type II fiber areas, only in females with high-power profiles.

中文翻译：

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年轻未训练女性的外侧腓肌肌纤维成分和束长度之间的弱关联

这项研究的目的是研究个体的股外侧肌肌肉纤维长度与纤维类型组成之间的关系，而这些个体很少受到系统的阻力/力量训练的影响。在60名女性体育学生中（年龄：21.03±2.1岁，体重：59.8±9.7 kg，身高：166.2±6.5 cm），他们没有系统的训练，瘦身，VL肌肉结构和纤维成分类型方面的经验，评估了反跳动作（CMJ）的性能以及等距腿部受力的速率。分析了所有参与者以及根据其最大反向运动跳跃力分配的两个相等编号的组（高功率或低功率组）的数据。发现II型肌纤维百分比与束长度之间存在显着但低的相关性（N = 60，p＜0.05）。发现IIa型和IIx型肌纤维百分比横截面积（％CSA）与束长度之间存在显着相关性（N = 60； r = 0.321和r = 0.378；p <0.05）。高功率组的这些相关性较高（r = 0.499，r = 0.522；p <0.05），而低功率组的相关性较低，且无统计学意义。力量/力量表现的最佳预测指标是下肢的瘦体重（r = 0.389–0.645，p <0.05）。这些结果表明，在系统训练很少的女性中，仅在具有高功率特征的女性中，束长度可能与II型纤维区域弱相关。