Fitness, physical activity, or sedentary patterns? Integrated analysis with obesity surrogates in a large youth sample.

OBJECTIVE: Physical fitness (PF) and physical activity (PA) are inversely associated with body mass index and waist circumference (WC), whereas sedentary time (ST) seems to boost obesity in youth. The aim was to examine the associations of each selected PF test, PA-related exposures, and specific ST patterns with obesity and determine the most relevant ones, in a large sample of a school-aged adolescent. METHODS: The sample consisted of 2696 Portuguese youth aged 10 to 18 years. Height, weight, and WC were measured. PA and ST components were measured using accelerometry. PF was evaluated using a battery of tests. RESULTS: The Progressive Aerobic Cardiovascular Endurance Run (PACER) and push-up tests seemed to be the exposures that presented the strongest and more consistent associations with obesity, independent of PA/ST profiles (P < .05). The second exposure of relevance for adolescent obesity level was the breaks in ST with a negative relationship regardless of PA/PF profiles (P < .05). Finally, ST accumulated in periods of <30 minutes, and moderate-to-vigorous PA were favorably associated with obesity, independent of ST/PF. CONCLUSIONS: Independent of PA and ST, cardiorespiratory fitness (CRF), measured by PACER, was associated with obesity markers. This may be in part due to the dependence of PACER performance on adiposity. Also, limiting prolonged ST and promoting interruptions in this behavior were associated with obesity. These associations suggest that future research should examine other strategies beyond PA promotion for tackling obesity that consider CRF and breaking ST.

Effects of Physically Active Lessons on Movement Behaviors, Cognitive, and Academic Performance in Elementary Schoolchildren: ERGUER/Aracaju Project.

BACKGROUND: To evaluate the effects of the introduction of physically active lessons on movement behaviors, cognitive, and academic performance in schoolchildren. METHODS: This was a cluster-controlled trial. A total of 61 students from the second year of elementary school in a public school in Brazil made up 2 intervention classes (n = 34) with the introduction of physically active lessons and 2 control classes (n = 27). Sedentary behavior, physical activity, cognitive, and academic performance were evaluated in 3 moments, which were compared using models of generalized estimating equations. RESULTS: The intervention was effective for reducing the standing time between the baseline and 3 months while increasing the walking time between baseline and 3 months and baseline and 9 months. There was a reduction in time in stationary activities and increased time in light physical activities between all moments. The intervention group increased their performance in the go/no go test, showing a smaller number of errors between the baseline and 3 months and baseline and 9 months, and a reduction in the test time between baseline and 3 months. No impact on students' academic performance was observed. CONCLUSION: Physically active lessons improve movement behaviors and cognitive functions among elementary schoolchildren.