摘要：Introduction:There is scientific evidence pointing out than children who do not engage in above 60 minutes of day of moderate-to-vigorous physical activity coincides with overweight and obesity,in physical education the teacher can be an influence in its contents and guide regarding the intensity of the physical activity of the students. The study aimed to compare the moderate-to-vigorous physical activity and perceived exertion among fourth,fifth and sixth grade children in Physical Education classes given by teachers with seniority lower or higher than 16 years. Material and Methods: Seventy physical education lessons conducted by teachers with ˂ than 16 years of experience (n=47) and teachers with ≥ of 16 years of experience (n=23) were evaluated among fourth,fifth and sixth grade children (Mean age=10.4±.3 years),using the System for observing fitness and instruction time (SOFIT) to assess the moderate-to-vigorous physical activity quantified the intensity as the proportion of time than students engaged in walking and very active physical activity during physical education,also to determine the perceived exertion,the pictorial children's effort rating table (PCERT) was completed,after physical education lessons;children chose an option in an illustrated scale 1–10 perceived exertion. Results: A cross-sectional design was used,the equality of variance was calculated using the Student t test for independent samples resulting moderate-to-vigorous physical activity (P-value=.173) and perceived exertion (P-value=.356),α≤ more than 0.05. Conclusions: In both groups the moderate-to-vigorous physical activity did not achieve international guidelines of reach at least 50% of the lessons time engaged in walking and very active physical activity,the average value of perceived exertion was less than 5 points of the scale,which is insufficient to enhance physical fitness,it is recommended that future studies build on teachers seniority to feedback in strategies for involving children in moderate-to-vigorous physical activity as recommend the World Health Organization.
