Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, TX.
J Musculoskelet Neuronal Interact. 2021 Dec 1;21(4):455-463.
It is unclear whether peak torque and rate of torque development (RTD) measurements can characterize functional differences in older adults according to their performance on a six-minute walk test. This study aimed to examine the efficacy of isometric peak torque and RTD characteristics of the knee extensors to differentiate between functional status in older women who are able (higher functioning) versus those who are unable (lower functioning) to walk 550 m in six minutes.
Ten higher functioning (67±4 years) and 10 lower functioning (68±4 years) older women performed three isometric knee extension maximal voluntary contractions followed by a six-minute walk test. Peak torque and early (RTD100), late (RTD200), and maximum (Peak RTD) RTD measurements were obtained from each contraction.
The higher functioning group exhibited greater peak torque, Peak RTD, RTD100, and RTD200 compared to the lower functioning group (P≤0.011), with larger differences occurring for RTD characteristics (39.9-54.9%) than peak torque (20.3%). Multiple regression analysis indicated that RTD200 was the single best predictor of the distance covered during the six-minute walk test (R2=0.437, P=0.002).
These findings suggest that knee extensor muscle strength, and in particular RTD, may be an effective discriminator and predictor of walking performance ability in older women.
目前尚不清楚峰值扭矩和扭矩发展速率（RTD）的测量是否可以根据老年人在六分钟步行测试中的表现来描述其功能差异。本研究旨在检验等长峰值扭矩和膝关节伸肌 RTD 特征在区分能够（功能较高）和不能（功能较低）在六分钟内行走 550 米的老年女性的功能状态方面的有效性。
10 名功能较高的（67±4 岁）和 10 名功能较低的（68±4 岁）老年女性进行了三次等长膝关节伸展最大自主收缩，随后进行了六分钟步行测试。从每个收缩中获得峰值扭矩和早期（RTD100）、晚期（RTD200）和最大（Peak RTD）RTD 测量值。
与功能较低的组相比，功能较高的组表现出更大的峰值扭矩、Peak RTD、RTD100 和 RTD200（P≤0.011），RTD 特征（39.9-54.9%）的差异大于峰值扭矩（20.3%）。多元回归分析表明，RTD200 是六分钟步行测试中覆盖距离的最佳单一预测指标（R2=0.437，P=0.002）。
这些发现表明，膝关节伸肌力量，特别是 RTD，可能是区分和预测老年女性步行能力的有效指标。
