Sedentary Thresholds for Accelerometry-Based Mean Amplitude Deviation and Electromyography Amplitude in 7-11 Years Old Children

Ying Gao, Eero A. Haapala, Anssi Vanhala, Arja Sääkslahti, Merja Rantakokko, Arto Laukkanen, Arto J. Pesola, Timo Rantalainen, Taija Finni

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We investigated the ability of energy expenditure, movement sensing, and muscle activity to discriminate sedentary and non-sedentary activities in children. Thirty-five 7-11-year-old children participated in the study. Simultaneous assessment of oxygen uptake ((V) over dotO(2)), triaxial accelerometry, and thigh muscle electromyography (EMG) were performed during eight different sedentary and non-sedentary activities including lying down, sitting-, standing-, and walking-related activities, which were performed in a random order. Mean values of (V) over dotO(2), accelerometry, and EMG from the concurrent 2 min epochs during each activity were computed. Resting energy expenditure (REE) was measured during 30 min supine rest. Directly measured metabolic equivalent of tasks (METs, (V) over dotO(2) in activities/(V) over dotO(2) in REE) were calculated for each activity. Mean amplitude deviation (MAD) was computed for accelerometry. EMG was normalized for mean muscle activity during self-paced walking. The classification accuracy of METs, MAD, and EMG to discriminate sedentary activities from physical activities was investigated by receiver operating characteristic curves and optimal cut-offs based on maximal sensitivity and specificity. Mean (SD) REE was 5.0 +/- 0.8 ml/kg/min. MET, MAD, and EMG values ranged from 1.0 to 4.9, 0.0020 to 0.4146 g, and 4.3 to 133.9% during lying down and walking at 6 km/h, respectively. Optimal cut-offs to discriminate sedentary activities from non-sedentary activities were 1.3 for METs (sensitivity = 82%, specificity = 88%), 0.0033 g for MAD (sensitivity = 80%, specificity = 91%), and 11.9% for EMG (sensitivity = 79%, specificity = 92%). In conclusion, this study provides applicable thresholds to differentiate sitting and standing and sedentary and non-sedentary activities based on METs, MAD, and EMG in young children.
Original languageEnglish
Article number997
JournalFrontiers in Physiology
Number of pages9
Publication statusPublished - 7 Aug 2019
Externally publishedYes
MoE publication typeA1 Journal article-refereed

Fields of Science

  • resting energy expenditure
  • accelerometry
  • electromyography
  • sitting
  • standing
  • posture
  • TIME
  • 315 Sport and fitness sciences
  • 515 Psychology

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