Flatt Andrew A, Esco Michael R
Dept of Kinesiology, University of Alabama, Tuscaloosa, AL.
Int J Sports Physiol Perform. 2015 Nov;10(8):994-1000. doi: 10.1123/ijspp.2014-0556. Epub 2015 Mar 10.
This study evaluated the 7-d mean and coefficient of variation (CV) of supine and standing ultrashort log-transformed root mean square of successive R-R intervals multiplied by 20 (lnRMSSDx20) obtained with a smartphone application (app) in response to varying weekly training load (TL). In addition, the authors aimed to determine if these values could be accurately assessed in as few as 5 or 3 d/wk.
Nine women from a college soccer team performed daily heart-rate-variability measures with an app in supine and standing positions over 3 wk of moderate, high, and low TL. The mean and CV over 7, 5, and 3 d were compared within and between weeks.
The 5- and 3-d measures within each week provided very good to nearly perfect intraclass correlations (ICCs .74-.99) with typical errors ranging from 0.64 to 5.65 when compared with the 7-d criteria. The 7, 5, and 3-d supine CV and the 7-day standing CV were moderately lower during the low-load than the high-load week (P .003-.045, effect sizes 0.86-0.92), with no significant changes occurring in the other measures.
This study supports the use of the mean and CV of lnRMSSD measured across at least 5 d for reflecting weekly values. The supine lnRMSSDx20 CV as measured across 7, 5, and 3 d was the most sensitive marker to the changes in TL in the 3-wk period.
本研究评估了使用智能手机应用程序（app）获取的仰卧位和站立位连续R-R间期超短对数转换均方根乘以20（lnRMSSDx20）的7天平均值和变异系数（CV），以应对每周不同的训练负荷（TL）。此外，作者旨在确定这些值是否可以在每周仅5天或3天的测量中得到准确评估。
来自一支大学足球队的9名女性在3周的中等、高和低训练负荷期间，每天使用该应用程序在仰卧位和站立位进行心率变异性测量。比较了各周内以及各周之间7天、5天和3天的平均值和CV。
与7天标准相比，每周内5天和3天的测量提供了非常好到几乎完美的组内相关系数（ICC为0.74 - 0.99），典型误差范围为0.64至5.65。低负荷周的7天、5天和3天仰卧位CV以及7天站立位CV均适度低于高负荷周（P = 0.003 - 0.045，效应大小为0.86 - 0.92），其他测量无显著变化。
本研究支持使用至少5天测量的lnRMSSD平均值和CV来反映每周的值。在3周期间，7天、5天和3天测量的仰卧位lnRMSSDx20 CV是对训练负荷变化最敏感的指标。
