Related Experiment Video
Updated: May 10, 2026
Assessment of Physical Activity Intensity with Accelerometers and Oxygen Consumption
Published on: June 20, 2025
Physical activity intensities in youth: the effect of month of assessment
Pedro Silva1, André Seabra, Pedro Saint-Maurice
1CIAFEL (Research Centre in Physical Activity, Health and Leisure), Faculty of Sports .
Background:
There is clear evidence that environmental factors play an important role regarding physical activity (PA) and sedentary behaviour (SB) in youth. This short report highlights seasonal differences in the amount and intensities of PA and SB, in Portuguese youth.
Methods:
Three hundred and eighty-seven participants (aged 14.7 ± 1.9 years), 220 girls, used the Actigraph GT1M accelerometer for 7 days (15-second epochs), between January and June in 2008. PA and SB differences were assessed using an ANCOVA.
Results:
Boys had significantly higher values of PA, with the exception of Light intensity. Girls were significantly more sedentary. PA intensities and SB changed significantly according to gender and month of assessment. SB (Gender F = 16.32, p < 0.001; Month F = 2.95, p < 0.013), Light PA (Gender F = 9.30, p = 0.002; Month F = 8.37, p < 0.001; Gender*Month F = 2.24, p = 0.050), Moderate PA (Gender F = 40.04, p < 0.001), Vigorous PA (Gender F = 32.89, p < 0.001; Month F = 2.56, p = 0.027). Both genders increased PA from winter to summer months and SB decreased.
Conclusions:
Seasonality in PA intensities and SB suggest that interventions to promote PA and decrease SB must be tailored to take into consideration the month of the year they are going to be implemented and also gender characteristics.
