Abstract:

Introduction:
School physical education is the main social institution with the responsibility of promoting physical activity in young people (Sallis, 1997). It is crucial that physical education (PE) teachers design PE programs well so that they produce important benefits for health. However, there is evidence that either PE or teachers are not adequately filling this role. Research revealed that PE specialists provided students with only a few minutes of moderate to vigorous physical activity (PA) per PE class; this is a little time. Improving PA levels represents a principal objective for thwarting the current health condition.

Objective:
Evaluate the intensity and duration of physical efforts in PE classes in primary school, according to the different types of planning.

Methods:
240 sixth graders students from 10 elementary schools form Nuevo Leon state Mexico, participated in this research. 120 boys and 120 girls between 11 and 13 years old. Also, eight PE teachers, four of them made a written lesson plan and the other four planned it using a software. Students used an Accelerometer (Actigraph gt3x) placed on their non-dominant hand during the class. The accelerometer was set according to each student’s height, weight and sex.

Results:
The time for moderated activity at written planning was 34.52 minutes, which corresponds an effective time of 69.04% in class. For moderated activity at Software, planning was 26.31 minutes, which corresponds an effective time of 52.62% in class. Each session was 50 minutes long.
The corresponding medians of boys subgroup were 33.70 minutes (SD=10.48), and girls subgroup were 32.41 minutes (SD= 10.36). Once the comparison was made it is observed that, even though boys maintain a higher moderated PA than girls, there are not significant differences between both of them: t (238) =.96, p=.34
In relation to the average time according to each planning method, the written planning was 39.53 minutes (SD= 8.41) of moderated PA. The Software planning time was 26.59 minutes (SD= 7.9), which indicates that there is a significant difference between both kinds of planning, being higher the one estimated at the written planning: t (238) =12.29, p˂.001.
In girls case and the kind of planning used it was found that in the written, the median time of the moderated activity was 38.60 minutes (SD= 8.40) and for the software was 26.22 (SD= 8.23) which corresponds to a significant difference: t (118)=8.15, p˂.001
In boys case and the written planning kind, the median time of moderated physical activity was 39.53 minutes (SD= 8.41) and for software was 26.58 minutes (SD= 7.90) which corresponds to a significant difference: t (238) =12.29, p˂.001.

Conclusions:
The written planning was more effective than the software planning class. Besides the fact that PE classes have a short duration, students practice moderate to vigorous PA during one third of the class, with a poor significant contribution to students' level of PA.

References:
[1] J. F. Sallis, J. E. Alcaraz, T. L. McKenzie, M. F. Hovell, B. Kolody, and P. R. Nader, “Parent behavior in relation to physical activity and fitness in 9-year-olds,” American Journal of Diseases of Children, vol. 146, pp. 1383–1388,1997.

Keywords:

Physical activity, accelerometer, physical education.