Seasonal changes in children's physical activity: an examination of group changes, intra-individual variability and consistency in activity pattern across season.
BACKGROUND
Components of activity that are more variable over time may be more susceptible to manipulation in activity interventions.


OBJECTIVE
The present study examined variability and consistency of components of children's activity across season.


METHODS
Sixty-four 9-11-year-old children wore an accelerometer for 6 days during winter and summer. Activity bouts (>or=4 s) greater than light (>or=LIGHT), moderate (>or=MOD) and vigorous (>or=VIG) intensity were recorded.


RESULTS
Intra-individual variability of the activity components across season was greater for bout frequency (CV: >or=LIGHT = 6.6-9.9%, >or=MOD = 10.7-16.1%, >or=VIG = 17.0-26.8%) than bout intensity or duration (CV: >or=LIGHT = 3.4-7.4%, >or=MOD = 3.6-7.8%, >or=VIG = 4.2-10.0%, p<0.05) and for the frequency of >or=VIG bouts compared to the frequency of >or=LIGHT and >or=MOD bouts (p<0.05). All components of the activity pattern tended to track consistently when assessing >or=LIGHT and >or=MOD bouts (intra-class correlations (ICC) = 0.47-83, p<0.05), >or=VIG bouts in boys (ICC = 0.69-0.77, p<0.01) and frequency of >or=VIG bouts in girls (ICC = 0.82, p<0.01).


CONCLUSIONS
Bout frequency was the most variable component of activity across season. However, children tended to maintain their rank for bout frequency. It would be of interest to investigate whether bout frequency can be manipulated in an activity intervention.
School of Sport and Health Sciences, University of Exeter, St Luke's Campus, Exeter, UK. a.v.rowlands@exeter.ac.uk
Ann V
AV
Rowlands
Emma L
EL
Pilgrim
Roger G
RG
Eston
D002648:Child; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D012621:Seasons; D012727:Sex Characteristics; D013997:Time Factors