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The level and tempo of children's physical activities: an observational study
R C Bailey1, J Olson, S L Pepper
1Department of Anthropology, University of California, Los Angeles 90024, USA.
Insights
Children engage in frequent, short bursts of physical activity, with intense activities lasting only seconds. Understanding these patterns is key to child development and physiological processes.
Area of Science:
- Pediatrics
- Exercise Physiology
- Child Development
Background:
- Quantifying children's physical activity is crucial for understanding growth and development.
- Previous methods often lack detailed quantification of activity duration and intensity.
- Free-ranging, naturalistic observation provides ecologically valid data.
Purpose of the Study:
- To develop and validate an observational system for quantifying children's physical activity.
- To assess the duration, intensity, and frequency of physical activities in children under natural conditions.
- To analyze energy expenditure patterns based on observed activity.
Main Methods:
- Developed a novel observational system to record activity duration, intensity, and frequency every 3 seconds.
- Utilized indirect calorimetry for laboratory calibration of oxygen consumption (VO2) during coded activities.
- Observed 15 children (aged 6-10) in Southern California during 4-hour blocks.
Main Results:
- Children spent 77.1% of time in low-intensity activities and only 3.1% in high-intensity activities.
- Median duration for low and medium intensity activities was 6 seconds; high-intensity activities averaged 3 seconds.
- Observed pattern: short bursts of intense activity interspersed with low/moderate intensity intervals.
Conclusions:
- Children's physical activity comprises short, intense bursts rather than sustained moderate or vigorous activity.
- The developed observational system offers a more comprehensive assessment of physical activity patterns than traditional methods.
- These findings have implications for understanding the relationship between activity patterns and physiological processes in child development.
Abstract:
We develop an observation system that quantifies the duration, intensity, and frequency of children's physical activities. We use this system to assess the level and tempo of energy expenditure under free-ranging, natural conditions experienced by 15 children aged 6-10 yr in southern California. Observations were recorded every 3 s during 4-h time blocks from 8:00 a.m.-8:00 p.m. Agreement among observers using the coding system was 91%. Using indirect calorimetry, calibration studies in the laboratory determined VO2 (ml.min-1.min-1) during each coded activity, and activities were categorized by intensity (low, medium, or high). Subjects were found to engage in activities of low intensity 77.1% of time and activities of high intensity 3.1% of time. The median duration of low and medium intensity activities was 6 s, of high intensity activities only 3 s with 95% lasting less than 15 s. Children engaged in very short bursts of intense physical activity interspersed with varying intervals of low and moderate intensity. These findings may be important for discovering how children's activity patterns under natural conditions influence physiological processes leading to growth and development. This study demonstrates the advantages of using an observational system that captures more than the intensity and frequency of children's activities to include duration and the length of intervals between activities of varying intensity.