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ORIGINAL ARTICLE  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2018 April;58(4):369-76

DOI: 10.23736/S0022-4707.16.06704-9

Copyright © 2016 EDIZIONI MINERVA MEDICA

language: English

Characteristics of children’s physical activity during active play

Asal MOGHADDASZADEH, Veronica JAMNIK, Angelo N. BELCASTRO

Pediatric Exercise Science Laboratory and Muscle Health Research Center, School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, ON, Canada


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BACKGROUND: Emerging evidence suggests that oxygen consumption (VO2) for self-paced physical activity (PA) is underestimated when applying laboratory-based treadmill (TM)-derived regression equations. This study examines the accelerometer (ACC) characteristics for paced TM PA and self-paced children’s PA to ascertain if the predictable regulated patterns of paced PA are implicated in the inferior estimates of VO2.
METHODS: Children’s (9.3±1.2 years) (N.=21) VO2 (portable oxygen analyzer) and PA (accelerometry) were measured for paced treadmill PA (4-10 km/h). Active playing of children’s games in a camp setting was used for self-paced PA. Treadmill and self-paced PA were compared by linear regression and Bland-Altman analysis. Relative contribution of each axes (% axis difference) for paced and self-paced PA were assessed (N.=21).
RESULTS: The VO2 responses during paced treadmill exercise was linear with ACC quantified PA (for vertical axis r=0.95±0.03 and for vector magnitude [VM] r=0.95±0.05, P>0.05). During self-paced PA, the VO2 responses for ACC quantified PA were not linear (for vertical axis r=0.20±0.11 and for VM r=0.25±0.09) over the same range of ACC PA (0-1500 counts/10 s). VO2 estimates for self-paced PA (using TM-derived equations) were underestimated (P<0.05) across the range of intensities, which increased as the intensity of PA increased (>6 METs). Comparing paced versus self-paced PA the % axis dominance (i.e., difference between the highest and lowest axis) contribution to PA was 41±14% for paced and 3±2% for self-paced PA (P<0.05).
CONCLUSIONS: This study reveals that the inferior estimates of VO2 for self-paced PA (using-derived linear equations) is attributable to the presence of a dominant axis with paced TM PA, which inflates the calculation of VM and the predicted VO2 for self-paced PA where no % axis difference exists.


KEY WORDS: Child - Oxygen consumption - Exercise

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