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Author：Tsung-Lin Chiang; Chu Chen; Shih-Hsuan Chan; Yu-Chin Lin; Huey-June Wu
Period/Date/Page：Vol. 26 No. 1 (2024 / 03 / 31) ， P55 - 72
DOI：10.5297/ser.202403_26(1).0004
Estimating Wrist Acceleration Thresholds for Sedentary Behavior and Different Levels of Physical Activity Intensity in Obese Adults Using a Wearable Device
Abstract：There is limited research evidence of acceleration data to quantify physical activity (PA) intensity in obese people. Recently, researchers have tended to establish individualized acceleration thresholds for obese people regarding PA levels. Therefore, the purpose of this study was to estimate the wrist acceleration thresholds of sedentary behavior (SB), and light, moderate to vigorous PA (LPA, MVPA) in obese adults using a wearable device. A total of 52 obese adults were recruited in the current study. Subjects performed a 5-minute seated resting oxygen consumption measurement at the beginning of the experiment, and followed by standing resting and incremental continuous walking test. The speeds of continuous walk stages were set at 3.2, 4.0, 4.8, 5.6, 6.4 km/hr. Each phase lasted for 5 minutes. The accelerations along the X, Y, Z axes and oxygen uptake were recorded during the entire experiment. Acceleration count (ACC) per second was calculated by the formula with √(X^2 + Y^2 + Z^2) - g at the triaxial acceleration values. Metabolic equivalent of task (MET) was derived from resting and exercising oxygen intake (VO_2). Results showed that: The correlation between ACC and METs was r = .83-.86 for all subjects. In addition, ACC has an excellent discriminative power for different PA intensity threshold models. SB acceleration threshold in men was 10.10 mg and 13.75 mg in women. LPA in men was 41.20 mg and 32.90 mg in women, MVPA was 105.70 mg in men and 109.25 mg in women. We conclude that the wearable device is an effective tool to establishing wrist acceleration thresholds in SB and LPA to MVPA in obese adults. It will be an effective tool for quantifying long-term PA intensity in daily life. (Full text)
