title: Energetic Assessment of the Nonexercise Activities under Free-Living Conditions.
abstract: Nonexercise activities (NAs) are common types of physical activity in daily life and critical component in energy expenditure. However, energetic assessment of NA, particularly in free-living subjects, is a technical challenge. In this study, mechanical modeling and portable device were used to evaluate five common types of NA in daily life: sit to stand, lie to sit, bowing while standing, squat, and right leg over left. A human indirect calorimeter was used to measure the activity energy expenditure of NA. Mechanical work and mechanical efficiency of NA were calculated for mechanical modeling. Thirty-two male subjects were recruited for the study (20 subjects for the development of models and 12 subjects for evaluation of models). The average (mean ± SD) mechanical work of 5 NAs was 2.31 ± 0.50, 2.88 ± 0.57, 1.75 ± 0.55, 3.96 ± 1.25, and 1.25 ± 0.51 J/kg·m, respectively. The mean mechanical efficiencies of those activities were 22.0 ± 3.3%, 26.5 ± 5.1%, 19.8 ± 3.7%, 24.0 ± 5.5%, and 26.3 ± 5.5%. The activity energy expenditure estimated by the models was not significantly different from the measurements by the calorimeter (p > 0.05) with accuracies of 102.2 ± 20.7%, 103.7 ± 25.8%, 105.6 ± 14.6%, 101.1 ± 28.0%, and 95.8 ± 20.7%, respectively, for those activities. These findings suggest that the mechanical models combined with a portable device can provide an alternative method for the energetic analysis of nonexercise activities under free-living condition.
authors: School of Biomedical Engineering, Capital Medical University, Beijing 100069, China; Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Beijing 100069, China.
authors: Shijie
authors: 0000-0001-7639-4139
authors: S
authors: Sun
authors: Jiangsu Research Institute of Sport Science, Nanjing 210033, China.
authors: Qiang
authors: 0000-0002-0179-1612
authors: Q
authors: Tang
authors: School of Biomedical Engineering, Capital Medical University, Beijing 100069, China; Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Beijing 100069, China.
authors: Haiying
authors: 0000-0001-7376-4456
authors: H
authors: Quan
authors: Jiangsu Research Institute of Sport Science, Nanjing 210033, China.
authors: Qi
authors: 0000-0001-8214-3846
authors: Q
authors: Lu
authors: Minisun, LLC, Fresno, CA 93720, USA.
authors: Ming
authors: 0000-0001-7610-6707
authors: M
authors: Sun
authors: School of Biomedical Engineering, Capital Medical University, Beijing 100069, China; Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Beijing 100069, China.
authors: Kuan
authors: 0000-0003-4195-1198
authors: K
authors: Zhang
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D001696:Biomechanical Phenomena; D002153:Calorimetry, Indirect; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D008954:Models, Biological; D055815:Young Adult