Comparing the standards of one metabolic equivalent of task in accurately estimating physical activity energy expenditure based on acceleration

ABSTRACT

The purpose of the study is to analyse how the standard of resting metabolic rate (RMR) affects estimation of the metabolic equivalent of task (MET) using an accelerometer. In order to investigate the effect on estimation according to intensity of activity, comparisons were conducted between the 3.5 ml O₂ · kg⁻¹ · min⁻¹ and individually measured resting VO₂ as the standard of 1 MET. MET was estimated by linear regression equations that were derived through five-fold cross-validation using 2 types of MET values and accelerations; the accuracy of estimation was analysed through cross-validation, Bland and Altman plot, and one-way ANOVA test. There were no significant differences in the RMS error after cross-validation. However, the individual RMR-based estimations had as many as 0.5 METs of mean difference in modified Bland and Altman plots than RMR of 3.5 ml O₂ · kg⁻¹ · min⁻¹. Finally, the results of an ANOVA test indicated that the individual RMR-based estimations had less significant differences between the reference and estimated values at each intensity of activity. In conclusion, the RMR standard is a factor that affects accurate estimation of METs by acceleration; therefore, RMR requires individual specification when it is used for estimation of METs using an accelerometer.

KEYWORDS:

• Acceleration
• accelerometer
• metabolic equivalent of task
• physical activity energy expenditure
• resting metabolic rate

Acknowledgements

This work was supported by the Research fund of Survivability Technology Defense Research Center of Agency for Defense Development of Korea (No. UD150013ID).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Survivability Technology Defense Research Center of Agency for Defense Development of Korea: [Grant Number UD150013ID].