Bassett David R, John Dinesh, Conger Scott A, Rider Brian C, Passmore Ryan M, Clark Justin M
1Department of Kinesiology, Recreation, and Sport Studies, University of Tennessee, Knoxville, TN; and 2Department of Health Sciences, Northeastern University, Boston, MA.
Med Sci Sports Exerc. 2014 Oct;46(10):2025-9. doi: 10.1249/MSS.0000000000000326.
The activPAL is an accelerometer-based monitor worn on the thigh that classifies daily activities into three categories (sitting/lying down, standing, and stepping). The monitor discriminates between sitting/lying and the upright position by detecting the inclination of the thigh. It detects stepping from the acceleration versus time wave form. However, a current limitation of the activPAL is that it does not discriminate between sitting and lying down.
This study aimed to determine whether placing a second activPAL monitor on the torso would allow the detection of seated versus lying postures.
Fifteen healthy adults (18-55 yr of age) wore an activPAL on the right thigh and another activPAL over the right rib cage. Both monitors were synchronized and initialized to record data in 15-s epochs. Participants performed a semistructured routine of activities for 3 min each. Activities included lying down (while supine, prone, and on the side), sitting, standing, sweeping, treadmill walking at 3 mph, and treadmill running at 6 mph. The spatial orientation of the thigh and chest monitors was used to determine body posture, and the activPAL on the thigh was used to detect ambulation.
The use of two activPAL devices enabled four behaviors to be accurately classified. The percentages of observations that were classified accurately were as follows: lying down (100%), sitting (100%), standing/light activity in the upright position (90.8%), and stepping (100%).
The current method allows researchers to obtain more detailed information on postural allocation compared with that in the use of a single activPAL on the thigh.
activPAL是一种佩戴在大腿上的基于加速度计的监测器，可将日常活动分为三类（坐/躺、站立和行走）。该监测器通过检测大腿的倾斜度来区分坐/躺和直立姿势。它从加速度与时间的波形中检测行走。然而，activPAL目前的一个局限性是它无法区分坐姿和躺姿。
本研究旨在确定在躯干上放置第二个activPAL监测器是否能够检测坐姿与躺姿。
15名健康成年人（年龄在18 - 55岁之间）在右大腿佩戴一个activPAL，在右胸腔上方佩戴另一个activPAL。两个监测器同步并初始化，以15秒的时间段记录数据。参与者每项活动进行3分钟的半结构化日常活动。活动包括躺卧（仰卧、俯卧和侧卧）、坐着、站立、扫地、以每小时3英里的速度在跑步机上行走以及以每小时6英里的速度在跑步机上跑步。利用大腿和胸部监测器的空间方向来确定身体姿势，大腿上的activPAL用于检测行走。
使用两个activPAL设备能够准确分类四种行为。准确分类的观察结果百分比如下：躺卧（100%）、坐着（100%）、直立站立/轻度活动（90.8%）和行走（100%）。
与仅在大腿上使用单个activPAL相比，当前方法使研究人员能够获得关于姿势分配的更详细信息。
