Maximal explosive muscle power in obese and non-obese prepubertal children

The objectives of the present study was to compare the maximal explosive muscle power developed by the lower limbs in obese and non-obese prepubertal children.

Twenty-five obese [mean body mass index (BMI) z-score: 2.4] and 30 non-obese (mean BMI z-score: 0) children aged 8-12 years, participated in this study. Body composition was measured by bioelectrical impedance analysis and the maximal explosive power of the lower limbs was assessed by the Exercise-Ergometer (a sledge dynamometer).

Absolute peak force (F(peak)) was higher in obese than in non-obese children by 18.2% (P<0.001). Peak speed (v(peak)) was not significantly different between groups (P = 0.504). Consequently, absolute peak power (W'(peak)) was higher in obese than in non-obese children (+19.3%, P = 0.021). Considering gender differences, absolute F(peak) and v(peak) were higher in boys than in girls by +12.3 and +17.4% (P<0.05), respectively, thus yielding higher absolute W'(peak) values in boys as compared to girls (+26.1%, P<0.001). Finally, W'(peak) normalized for fat-free mass (FFM) was not different between obese and non-obese children but higher in boys than in girls (+24.5%, P<0.001).

Power generation capability per unit of FFM was similar between obese and non-obese children but was significantly higher in boys than girls. On the clinical practice it seems important to devote supplementary care to sustain and improve the motor function of obese and non-obese girls.