Nordine Lazaar

Effect of physical activity intervention on body composition in young children: influence of body mass index status and gender.

Aim: To fight overweight and obesity in childhood, this study proposes an additional physical activity (PA) in young children aged 6–10 years. The objective was to evaluate the effect of school‐based PA on the body composition according to body mass index (BMI) categories (nonobese vs. obese) and gender.

Age differences in human skeletal muscle fatigue during high-intensity intermittent exercise

It has been shown at similar relative work rates that children have higher resistance to fatigue than adults during repeated bouts of high‐intensity exercise. This age‐related difference in fatigue resistance may be explained by factors including muscle mass, muscle morphology, energy metabolism and neuromuscular activation.

Bedtime and sleep timing but not sleep duration are associated with eating habits in primary school children.

Objective:In the context of childhood obesity progression, sleep patterns have been associated with unhealthy eating habits and energy intake. The association between several eating habits and sleep patterns in children has been recently studied. The aim of this study was to explore the association between sleep patterns, eating habits, and physical fitness in primary school children. Methods:A total of 236 children of 6 to 10 years old were recruited. Anthropometric characteristics and body composition were measured, and cardiorespiratory (20-m shuttle run test) and musculoskeletal (squat jump and cycling peak power) fitness tests were performed. Parents were asked to fill out an eating habits questionnaire, and children were classified into 4 categories as a function of the number of eating risk factors they presented. Parents completed a questionnaire about their childs bedtime and waking hours during weekdays and weekends. Results:Weight (p < .01), waist circumference, and fat mass (p < .05) were significantly higher in late sleepers (27.6 ± 6.3 kg; 60.1 ± 7.6 cm; 19.52 ± 7.44) compared with normal sleepers (25.4 ± 3.7 kg; 58.2 ± 4.9 cm; 17.44% ± 6.23%). None of the physical fitness parameters were associated with sleep duration, bedtime, wake-up time, nor were they significantly different between late and normal sleepers. Bedtime was significantly earlier in children consuming breakfast everyday (08:30 vs 09:00 PM, p < .01); later in children snacking (09:15 vs 09:30 PM, p < .05) or watching TV at lunch (10:00 vs 09:30 PM, p < .05). There is an association between the proportion of normal and late sleepers and the accumulation of healthy eating habits (p < .001). Conclusion:Bedtime and sleep timings (normal or late sleepers) are associated with eating habits in primary school children. It seems necessary to consider the number of unhealthy eating habits adopted by children when studying these associations.

Modalities of submaximal exercises on ratings of perceived exertion by young girls: a pilot study.

This pilot study compared the rating of perceived exertion scores (RPE) in young girls for two modalities of exercises (running vs cycling) performed at the same absolute heart rate. 23 girls, ages 8 to 11 years, from a gymnastic club performed graded, intermittent, and submaximal running and cycling exercises at a similar absolute heart rate (±5 bpm). These exercises consisted of three stages of 3 min. duration separated by 1-min. recovery intervals. RPE was estimated using the Childrens Effort Rating Table scale at the end of each stage of each exercise. Mean ratings were only significantly different during cycling, compared to running for the Stage 3 (cycling 5.3 ± 2.7 and running 7.0 ± 1.9, p < .05). During low exercise intensity, measured as heart rate, the modality of exercise does not seem to affect RPE. In contrast, with high heart rates, RPE are higher during cycling than running, so it is necessary to take account of the type of exercise.