Faculty of Health Sciences, Department of Physical Therapy, The Neuromuscular & Human Performance Laboratory, Ariel University, Ariel, Israel.
Vrije Universiteit, Department of Human Movement Sciences, Amsterdam Movement Sciences, Amsterdam, The Netherlands.
J Biomech. 2022 Oct;143:111269. doi: 10.1016/j.jbiomech.2022.111269. Epub 2022 Aug 25.
We aimed to verify whether the computational approaches previously proposed to analyze stability after a single-leg drop-jump (SLDJ) could be applied to a population of middle-aged adults. Fifteen middle-aged (56.4 ± 4.6 years) and 15 young adults (26.7 ± 3.9 years) performed five SLDJs. Stabilization measurements included (1) time to stabilization (TTS) based on vertical ground reaction force (GRF) (TTSv) and a fixed stabilization threshold; (2) TTS based on medio-lateral GRF (TTSml) using five different methods to preprocess the signal and stabilization threshold; (3) early medio-lateral stabilization- the averaged absolute values of the GRF in 0.2-1.4 s post-landing; (4) late medio-lateral stabilization - the averaged absolute values of the GRF at 1 s-5 s after landing. TTSv showed longer TTS values in middle-aged participants. In addition, middle-aged adults showed greater sway in late stabilization. However, TTSml values varied considerably between calculation methods, and early stabilization showed no significant differences between groups except in the first 0.2 s after landing. The results of the current study suggest that TTS calculations are sensitive to signal and threshold selection, and to the processing method. Calculations based on a fixed threshold are more appropriate for studying dynamic postural stability in middle age. With appropriate method selection, a decreased stabilizing performance can be demonstrated in middle-aged adults compared to young adults.
我们旨在验证之前提出的用于分析单腿跳下（SLDJ）后稳定性的计算方法是否适用于中年人群。15 名中年（56.4±4.6 岁）和 15 名年轻成年人（26.7±3.9 岁）进行了 5 次 SLDJ。稳定性测量包括（1）基于垂直地面反力（GRF）的稳定时间（TTSv）和固定稳定阈值；（2）基于中侧 GRF 的 TTS（TTSml），使用五种不同的信号预处理方法和稳定阈值；（3）早期中侧稳定性-着陆后 0.2-1.4 秒内 GRF 的平均绝对值；（4）晚期中侧稳定性-着陆后 1 秒至 5 秒内 GRF 的平均绝对值。TTSv 显示中年参与者的 TTS 值较长。此外，中年参与者在晚期稳定性方面表现出更大的摆动。然而，TTSml 值因计算方法而异，早期稳定性除了在着陆后最初的 0.2 秒外，两组之间没有显著差异。本研究的结果表明，TTS 计算对信号和阈值选择以及处理方法敏感。基于固定阈值的计算更适合研究中年时期的动态姿势稳定性。通过适当的方法选择，可以证明与年轻成年人相比，中年成年人的稳定性能降低。
