Objectives

This study aimed i) to assess the assumptions made in the sit-to-stand (STS) muscle power test [body mass accelerated during the ascending phase (90% of total body mass), leg length (50% of total body height) and concentric phase (50% of total STS time)], ii) to compare force plate-derived (FPD) STS power values with those derived from the STS muscle power test; and iii) to analyze the relationships of both measurements with physical function.

Material and methods

Fifty community-dwelling older adults (71.3 ± 4.4 years) participated in the present investigation. FPD STS power was calculated as the product of measured force (force platform) and velocity [difference between leg length (DXA scan) and chair height, divided by time (obtained from FPD data and video analysis)], and compared to estimated STS power using the STS muscle power test. Physical function was assessed by the timed-up-and-go (TUG) velocity, habitual gait speed (HGS) and maximal gait speed (MGS). Paired t-tests, Bland-Altman plots and regressions analyses were conducted.

Results

Body mass accelerated during the STS phase was 85.1 ± 3.8% (p < 0.05; compared to assumed 90%), leg length was 50.7 ± 1.3% of body height (p < 0.05; compared to 50%), and measured concentric time was 50.3 ± 4.6% of one STS repetition (p > 0.05; compared to assumed 50%). There were no significant differences between FPD and estimated STS power values (mean difference [95% CI] = 6.4 W [−68.5 to 81.6 W]; p = 0.251). Both FPD and estimated relative (i.e. normalized to body mass) STS power were significantly related to each other (r = 0.95 and ICC = 0.95; p < 0.05) and to MGS and TUG velocity after adjusting for age and sex (p < 0.05).

Conclusions

Estimated STS power was not different from FPD STS power and both measures were strongly related to each other and to maximal physical performance.

中文翻译：

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坐姿肌肉力量测试：老年人估计力和推力板产生的机械力量之间的比较以及它们与身体功能的关系

目标

这项研究的目的是：i）评估从坐到站（STS）肌肉力量测试所做的假设[在上升阶段，体重加速（占总体重的90％），腿长（占总身高的50％）和同心阶段（占总STS时间的50％）]，ii）比较推力板衍生（FPD）的STS功率值与从STS肌肉功率测试得出的值；iii）分析两种测量与物理功能之间的关系。

材料与方法

五十名社区居住的老年人（71.3±4.4岁）参加了本调查。将FPD STS功率计算为测得的力（力平台）和速度的乘积[腿长（DXA扫描）与椅子高度之间的差，再除以时间（从FPD数据和视频分析获得）]，并与估算的STS功率进行比较使用STS肌肉力量测试。通过定时走步（TUG）速度，习惯步态速度（HGS）和最大步态速度（MGS）评估身体机能。进行配对t检验，Bland-Altman图和回归分析。

结果

在STS阶段加速的体重为85.1±3.8％（p  <0.05；与假定的90％相比），腿长为体重的50.7±1.3％（p  <0.05；与50％相比），测得的同心时间为一次STS重复的50.3±4.6％（p  > 0.05；与假定的50％相比）。FPD和估计的STS功率值之间没有显着差异（平均值差异[95％CI] = 6.4 W [-68.5至81.6 W]；p  = 0.251）。 调整了年龄和性别后，FPD和估计的相对（即相对于体重标准化）的STS功率彼此之间显着相关（r = 0.95和ICC = 0.95；p <0.05），并且与MGS和TUG速度显着相关（p  <0.05） 。

结论

估计的STS功率与FPD STS功率没有区别，并且这两种措施彼此之间密切相关，并且与最大的物理性能密切相关。