Speedtsberg Merete Brink, Zebis Mette Kreutzfeldt, Andersen Lars Louis, Søndergaard Rasmus, Hölmich Per, Aagaard Per, Bencke Jesper
Human Movement Analysis Laboratory, Department of Orthopaedic Surgery, Amager-Hvidovre Hospital, Copenhagen University Hospital, Copenhagen, Denmark.
Sports Orthopedic Research Center-Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital Amager-Hvidovre, Hvidovre, Denmark.
Scand J Med Sci Sports. 2025 Mar;35(3):e70036. doi: 10.1111/sms.70036.
The purpose of this study was to provide data-driven recommendations for assessing early-phase rate of torque development (RTD) in isometric knee extension and flexion, focusing on the optimal number of repetitions performed and trial selection criteria to ensure robust intersession reliability. Twenty subjects (10 males, 10 females) completed two test sessions with nine repetitions of unilateral "fast and strong" isometric contractions for the knee extensors and flexors. RTD was calculated from torque onset to 50 ms (RTD50) and 100 ms (RTD100), and peak RTD was assessed in a moving 50 ms interval within the first 100 ms (Peak50). Intersession reliability was assessed using intraclass correlation coefficient (ICC) for three to nine repetitions and four different criteria for trial selection. A mixed-effect linear regression model was performed with measured RTD as dependent variable with number of repetitions, selection criteria, and test session as independent variables. The results revealed high intersession reliability for RTD100 in knee extension (ICC 0.849-0.961) and flexion (ICC 0.835-0.944) across repetitions and selection criteria. Three repetitions were sufficient to optimize intersession reliability and measured values of knee extensor RTD. Assessment of knee flexor RTD required five repetitions to optimize reliability for RTD50 (ICC ≥ 0.700) and six repetitions to optimize absolute measured values of RTD100. Selection criteria based on peak RTD100 ensured optimal reliability and absolute RTD measurements for both peak50, RTD50 and RTD100. The assessment of knee flexion requires more repetitions than knee extension to ensure reproducible early-phase RTD outcomes.
本研究的目的是为评估等长膝关节伸展和屈曲时早期扭矩发展速率（RTD）提供数据驱动的建议，重点关注所执行重复次数的最佳值和试验选择标准，以确保不同测试时段间具有可靠的信度。20名受试者（10名男性，10名女性）完成了两个测试时段，对膝关节伸肌和屈肌进行了9次单侧“快速且有力”的等长收缩。RTD是从扭矩起始到50毫秒（RTD50）和100毫秒（RTD100）进行计算的，并且在最初100毫秒内的一个移动50毫秒间隔内评估峰值RTD（Peak50）。使用组内相关系数（ICC）评估三到九次重复以及四种不同试验选择标准下不同测试时段间的信度。以测量的RTD作为因变量，重复次数、选择标准和测试时段作为自变量进行混合效应线性回归模型分析。结果显示，在重复次数和选择标准范围内，膝关节伸展时RTD100（ICC 0.849 - 0.961）和屈曲时RTD100（ICC 0.835 - 0.944）具有较高的不同测试时段间信度。三次重复足以优化不同测试时段间的信度以及膝关节伸肌RTD的测量值。评估膝关节屈肌RTD需要五次重复以优化RTD50的信度（ICC≥0.700），六次重复以优化RTD100的绝对测量值。基于峰值RTD100的选择标准确保了Peak50、RTD50和RTD100的最佳信度和绝对RTD测量值。与膝关节伸展相比，评估膝关节屈曲需要更多的重复次数以确保可重复的早期RTD结果。
