Anaerobic recovery - a determinant of physical activity in obese children?

Abstract

Children preferentially move in an anaerobic way, with short spontaneous bursts of 15–30 seconds of high intensity activity being most characteristic. The ability to recover from these anaerobic bursts may determine further bouts of activity and we proposed that this ability is impeded in obese children, and therefore a determinant of their inactivity. An experiment was conducted to examine the hypothesis that obese children’s ability to recover from anaerobic movement is impaired, and this slowed recovery is predicted by physical activity level. Twenty 8–12 year-old Chinese children (10 normal weight and 10 obese) participated in the study. Physical activity was assessed over three days using an accelerometer, with data expressed as average vector magnitude counts (AVM). In the laboratory, anthropometric measurements were taken, and anaerobic recovery was assessed and expressed as the percent recovery when performing two 30-second Wingate anaerobic tests separated by a 2-minute rest period. Results indicated significant differences (p < 0.05) in: BMI (obese 24.8 ± 3.6 kg/m2; normal 14.9 ± 1.2 kg/m2); waist circumference (obese 81.7 ± 9.6 cm; normal 53.9 ± 2.2 cm); hip circumference (obese 94.4 ± 6.5; normal 68.2 ± 3.9), and percent recovery (obese 95 ± 12 %; normal 112 ± 17 %). No significant difference was found in physical activity level (obese 312 ± 158 AVM; normal 237 ± 58 AVM). Multiple stepwise regression found that percentage recovery was predicted by waist circumference only (r = 0.55, p < 0.05) when age, BMI, waist circumference, hip circumference, waist hip ratio, waist thigh ratio and AVM were added as independent variables. Although these findings are not conclusive, they provide evidence that obese children were less ready to start moving after finishing one bout of activity compared with normal weight children. However, the complex relationship between physical activity level, fatness and physiological function still requires