Introduction: Youth activity guideline compliance is generally low across most western countries and Dutch youth are no exception to this. Thirty-two percent of 4-11 year old boys and girls, and 15% of 12-17 year olds are currently meeting the physical activity (PA) guideline recommendations of one hour of daily moderate-to-vigorous PA (MVPA) (Hildebrandt, Ooijendijk, & Hopman Rock, 2008). Physical education (PE) has been attributed an important role in providing young people with physical activity (Kahn, et al., 2002). If sufficiently active, PE lessons could contribute to physical activity levels in youth. Therefore, the purpose of this study was to determine the overall intensity of Dutch primary and secondary school physical education (PE) lessons and the influence of various lesson characteristics on these intensity levels.
Methods: Heart rates were measured using the Polar Team System in a nationally distributed sample of 913 students in 40 schools (20 primary schools and 20 secondary schools) in the Netherlands. A total of 106 lessons were assessed, with 10 students per class (5 boys and 5 girls) wearing a heart rate monitor for the duration of their PE class. Teachers were asked not to deviate from their regular PE program and to carry out their lessons as they had planned. None of the lessons had a specifically planned physical activity intensity focus.
Results: Overall percentages lesson time in MVPA were 46.7% and 40.1% during primary school and secondary school PE respectively. Primary school students engaged in significantly more MVPA than did secondary school students (t (890) = 4.635, p<.001). Furthermore, results indicated a sharp decline in girls' PE intensity levels in secondary school, where boys were more active than girls (F (1,912) = 9,58, p<.01). Subsequent analyses of lesson content in secondary school students indicated that girls were less active during teamgames, but not during individual activities or lessons with a mixed subject (both teamgames and individual activities) (45.7% vs. 34.7% F (3,451) = 16.31, p<.001, figure 1).
Discussion: Our results show that one PE lesson roughly accounts for one-third of the daily amount of physical activity as prescribed by activity guidelines. Furthermore, previous research has shown that by including lesson intensity as an additional lesson goal it is relatively simple to increase lesson intensity (Verstraete, Cardon, De Clercq, & De Bourdeaudhuij, 2007). Therefore, increasing lesson intensity combined with increasing the number of weekly PE lessons seems an effective strategy to increase youth physical activity through PE. However, given the curricular and time constraints in most schools, PE should not be seen as a stand-alone solution for combating inactivity. Combined with other school-based PA opportunities (active transport, active breaks) however, PE could make a meaningful contribution to daily PA in youth. Finally, the high prevalence of coeducational teamgames (61% of all lessons) in the Dutch secondary school PE curricula might prevent girls from attaining similar physical activity levels to boys during PE. Therefore, more research is needed on maximising secondary school girls' participation during teamgames.