Department of Physiotherapy, Federal University of Sao Carlos, São Carlos-SP, Brazil.
Department of Gerontology, School of Arts, Sciences and Humanities, University of Sao Paulo, São Paulo-SP, Brazil.
J Strength Cond Res. 2021 Apr 1;35(4):1050-1057. doi: 10.1519/JSC.0000000000002888.
Fiogbé, E, Vassimon-Barroso, V, Catai, AM, de Melo, RC, Quitério, RJ, Porta, A, and Takahashi, ACdM. Complexity of knee extensor torque: effect of aging and contraction intensity. J Strength Cond Res 35(4): 1050-1057, 2021-Assessing the knee extensors' torque complexity in older adults is relevant because these muscles are among the most involved in functional daily activities. This study aimed to investigate the effects of aging and isometric contraction intensity on knee extensor torque complexity. Eight young (24 ± 2.8 years) and 13 old adults (63 ± 2.8 years) performed 3 maximal (maximum voluntary contraction [MVC], duration = 10 seconds) and submaximal isometric contractions (SICs, targeted at 15, 30, and 40% of MVC, respectively) of knee extensors. Torque signals were sampled continuously, and the metrics of variability and complexity were calculated basing on the SIC torque data. The coefficient of variation (CV) was used to quantify the torque variability. The torque complexity was determined by calculating the corrected approximate entropy (CApEn) and sample entropy (SampEn) and its normalized versions (NCApEn and NSampEn). Young subjects produced greater isometric torque than older adults, and the CV was similar between both groups except at the highest force level (40% MVC) where young subjects' value was higher. The major novel finding of this investigation was that although the knee extensor torque complexity is reduced in older adults, its relationship with contraction intensity is similar to young subjects. This means that despite the age-related decrease of the interactions between the components of the neuromuscular system, the organization of force control remains preserved in older adults, at least up to just below the force midrange.
菲奥格贝、E、瓦西蒙-巴罗索、V、卡泰阿、AM、德梅洛、RC、奎特里奥、RJ、波塔、A 和高桥、ACdM. 膝伸肌力矩的复杂性：衰老和收缩强度的影响。J 力量与条件研究 35(4):1050-1057, 2021-评估老年人膝关节伸肌的力矩复杂性很重要，因为这些肌肉是参与日常功能活动最多的肌肉之一。本研究旨在探讨衰老和等长收缩强度对膝伸肌力矩复杂性的影响。8 名年轻（24 ± 2.8 岁）和 13 名老年（63 ± 2.8 岁）成年人分别进行了 3 次最大（最大自主收缩[MVC]，持续时间=10 秒）和亚最大等长收缩（SIC，分别针对 15、30 和 40%的 MVC）的膝伸肌。连续采集扭矩信号，并根据 SIC 扭矩数据计算变异性和复杂性指标。变异系数（CV）用于量化扭矩变异性。通过计算校正近似熵（CApEn）和样本熵（SampEn）及其归一化版本（NCApEn 和 NSampEn）来确定扭矩复杂性。年轻受试者产生的等长扭矩大于老年受试者，除了在最高力水平（40%MVC）下，年轻受试者的 CV 值较高外，两组的 CV 值相似。本研究的主要新发现是，尽管老年人大腿伸肌的力矩复杂性降低，但与收缩强度的关系与年轻受试者相似。这意味着，尽管与年龄相关的神经肌肉系统组件之间的相互作用减少，但在力的中程范围内，力控制的组织在老年人中仍保持不变。
