1Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, England, UNITED KINGDOM; 2Exercise, Health, and Human Performance Group, Sansom Institute for Health Research, School of Health Sciences, University of South Australia, Adelaide, SA, AUSTRALIA; and 3Health and Use of Time Group, Sansom Institute for Health Research, School of Health Sciences, University of South Australia, Adelaide, SA, AUSTRALIA.
Med Sci Sports Exerc. 2013 Dec;45(12):2353-61. doi: 10.1249/MSS.0b013e31829ba765.
The aims of this study were to quantify the relation between ground reaction force (GRF) and peak acceleration from hip- and wrist-worn accelerometers and determine peak acceleration cut-points associated with a loading rate previously demonstrated as beneficial to bone (43 body weights (BW)·s⁻¹) in premenopausal women.
Forty-seven premenopausal women (age, 39.2 ± 5.6 yr; mass, 65.9 ± 11.0 kg; height, 1.67 ± 0.06 m) performed walking (slow, fast, and with bag), floor sweeping, running (slow and fast), jumping (low, <5 cm; high, >5 cm), and box drop (20 cm) trials. Peak accelerations were sampled at 100 Hz by GENEActiv and ActiGraph GT3X+ accelerometers (ActiGraph LLC, Pensacola, FL) worn at the hip (vertical and resultant) and the wrist (resultant). A force plate (960 Hz, AMTI) was used to assess peak vertical GRF and peak loading rate for eight steps per activity. Receiver operating characteristic curves were used to determine the optimal peak acceleration cut-points associated with a loading rate of 43 BW·s⁻¹ in 37 participants, and these cut-points were cross-validated in the remaining 10 participants.
For all activities combined, peak accelerations were positively and significantly (P < 0.001) correlated with peak vertical GRF (hip r > 0.8, wrist r > 0.7) and peak loading rate (hip r > 0.7, wrist r > 0.57). Irrespective of monitor type and wear site, peak acceleration discriminated between loading rates above and below 43 BW·s⁻¹ with high levels of accuracy (area under the curve >0.92, P < 0.001). Overall classification agreement was >85% for both monitors worn at either the wrist or hip in the cross-validation sample.
GENEActiv and ActiGraph GT3X+ accelerometers worn at the wrist or hip can be used as an unobtrusive tool to identify the occurrence of loading rates likely beneficial to bone in premenopausal women during their daily activity.
本研究旨在量化地面反作用力（GRF）与髋部和腕部加速度计记录的峰值加速度之间的关系，并确定与之前证明对绝经前女性骨骼有益（43 倍体重（BW）·s⁻¹）的加载速率相关的峰值加速度截断值。
47 名绝经前女性（年龄 39.2 ± 5.6 岁；体重 65.9 ± 11.0 kg；身高 1.67 ± 0.06 m）进行了行走（慢、快和带包）、地板清扫、跑步（慢和快）、跳跃（低，<5 cm；高，>5 cm）和跳箱（20 cm）试验。使用 GENEActiv 和 ActiGraph GT3X+加速度计（ActiGraph LLC，彭萨科拉，FL）以 100 Hz 的采样率在髋部（垂直和合成）和腕部（合成）记录峰值加速度。力台（960 Hz，AMTI）用于评估每个活动的 8 步的垂直峰值 GRF 和峰值加载速率。使用受试者工作特征曲线确定与 37 名参与者 43 BW·s⁻¹ 加载速率相关的最佳峰值加速度截断值，并在其余 10 名参与者中进行交叉验证。
对于所有活动，峰值加速度与垂直峰值 GRF（髋部 r > 0.8，腕部 r > 0.7）和峰值加载速率（髋部 r > 0.7，腕部 r > 0.57）呈正显著相关（P < 0.001）。无论监测器类型和佩戴部位如何，峰值加速度均能以较高的准确性区分高于和低于 43 BW·s⁻¹ 的加载速率（曲线下面积>0.92，P < 0.001）。在交叉验证样本中，两种监测器在腕部或髋部佩戴时的整体分类一致性均>85%。
在绝经前女性日常活动中，腕部或髋部佩戴的 GENEActiv 和 ActiGraph GT3X+加速度计可作为一种非侵入性工具，用于识别可能对骨骼有益的加载速率。
