Hendelman D, Miller K, Baggett C, Debold E, Freedson P
Department of Exercise Science, University of Massachusetts, Amherst 01003, USA.
Med Sci Sports Exerc. 2000 Sep;32(9 Suppl):S442-9. doi: 10.1097/00005768-200009001-00002.
This study was undertaken to examine the validity of accelerometry in assessing moderate intensity physical activity in the field and to evaluate the metabolic cost of various recreational and household activities.
Twenty-five subjects completed four bouts of overground walking at a range of self-selected speeds, played two holes of golf, and performed indoor (window washing, dusting, vacuuming) and outdoor (lawn mowing, planting shrubs) household tasks. Energy expenditure was measured using a portable metabolic system, and motion was recorded using a Yamax Digiwalker pedometer (walking only), a Computer Science and Application, Inc. (CSA) accelerometer, and a Tritrac accelerometer. Correlations between accelerometer counts and energy cost were examined. In addition, individual equations to predict METs from counts were developed from the walking data and applied to the other activities to compare the relationships between counts and energy cost.
Observed MET levels differed from values reported in the Compendium of Physical Activities, although all activities fell in the moderate intensity range. Relationships between counts and METs were stronger for walking (CSA, r = 0.77; Tritrac, r = 0.89) than for all activities combined (CSA, r = 0.59; Tritrac, r = 0.62). Metabolic costs of golf and the household activities were underestimated by 30-60% based on the equations derived from level walking.
The count versus METs relationship for accelerometry was found to be dependent on the type of activity performed, which may be due to the inability of accelerometers to detect increased energy cost from upper body movement, load carriage, or changes in surface or terrain. This may introduce error in attempts to use accelerometry to assess point estimates of physical activity energy expenditure in free-living situations.
本研究旨在检验加速度计在评估户外中等强度身体活动方面的有效性，并评估各种娱乐和家务活动的代谢成本。
25名受试者以一系列自行选择的速度完成了4次户外行走，打了两洞高尔夫球，并进行了室内（擦窗、掸尘、吸尘）和户外（割草、种植灌木）家务任务。使用便携式代谢系统测量能量消耗，并使用Yamax Digiwalker计步器（仅用于行走）、计算机科学与应用公司（CSA）加速度计和Tritrac加速度计记录运动情况。研究了加速度计计数与能量消耗之间的相关性。此外，根据行走数据建立了从计数预测代谢当量（METs）的个体方程，并将其应用于其他活动，以比较计数与能量消耗之间的关系。
观察到的MET水平与《体力活动简编》中报告的值不同，尽管所有活动都属于中等强度范围。行走时（CSA，r = 0.77；Tritrac，r = 0.89）计数与METs之间的关系比所有活动综合起来时（CSA，r = 0.59；Tritrac，r = 0.62）更强。根据平地行走得出的方程，高尔夫球和家务活动的代谢成本被低估了30 - 60%。
发现加速度计的计数与METs之间的关系取决于所进行的活动类型，这可能是由于加速度计无法检测到上身运动、负重、表面或地形变化导致的能量消耗增加。这可能会在试图使用加速度计评估自由生活状态下身体活动能量消耗的点估计值时引入误差。
