This review summarizes the research relating anaerobic function to growth among children and adolescents. Pediatric practitioners and scientists are always struck by the impressive accumulation of results relating to the cardiopulmonary system. However, anaerobic fitness has received much less research attention. This is surprising, considering that high-intensity exercises lasting only a few seconds is a more “natural” pattern during growth than prolonged low-intensity exercises. In anaerobic tasks or sport events such as sprint running, sprint swimming, sprint cycling, jumping, or throwing, the child’s performance is distinctly lower than that of the adult. This partly reflects the child’s lesser ability to generate mechanical energy from chemical energy sources during short-term intensive work or exercise. Because both intramuscular high energy phosphate kinetics and muscle cross-section vary during growth and maturation, this review examines some developmental aspects of energetic- and mechanical factors involved in anaerobic performance. Anaerobic muscle function and performance are quantitative traits influenced by several determinants such as genetic factors, age and gender, muscle fiber characteristics, hormonal and training factors. Because of ethical and methodological constraints when investigating healthy children, this review also includes fundamental work done on some animal models.
Emmanuel Van Praagh
Craig A. Williams, Eric Doré, James Alban and Emmanuel Van Praagh
This study investigated the differences in short-term power output (STPO) using three different cycle ergometers in 9-year-old children. A total of 31 children participated in three cycle ergometer sprint tests of 20 s duration: a modified friction braked Monark, a modified friction braked Ergomeca cycle ergometer, and a SRM isokinetic ergometer. Common indices of peak and mean power, peak pedal rate, time to peak power, and pedal rate were recorded. Indices of peak power 1 s for the Monark, Ergomeca and SRM ergometer were found to be 299 ± 55, 294 ± 55, 297 ± 53 W and mean power 20 s to be 223 ± 40, 227 ± 43 and 216 ± 34 W, respectively. The time to peak power was found to be 3 ± 2, 6 ± 2, 5 ± 3 s, respectively. The standard error of measurement was lower in mean 20-s power compared to 1-s peak power. Despite instrumentation and protocol differences these results demonstrate reproducibility in 9-year-old children that will allow researchers confidence in comparing STPO data obtained from different ergometers.
Emmanuel Van Praagh, Nicole Fellmann, Mario Bedu, Guy Falgairette and Jean Coudert
This study was done to determine the extent to which body composition accounts for differences in anaerobic characteristics between 12-year-old girls and boys. Peak leg power (PP), mean leg power (MP), percent body fat, fat free mass (FFM), and lean thigh volume (LTV) were determined by various tests. Pubertal stages and salivary testosterone concentration (in boys) were used to assess sexual maturation. Laboratory anaerobic indices were compared with performances in two running tests. Blood samples were taken for lactate determination. Absolute PP and MP outputs were similar in both sexes and were better correlated with LTV in girls, whereas in boys both PP and MP were highly correlated with FFM. Although nonsignificant gender difference in lean tissue was observed, PP and MP when corrected for LTV were significantly greater in boys than in girls. Factors other than the amount of lean muscle mass should be considered in explaining the gender differences in PP and MP in early pubertal children.
Rômulo Maia Carlos Fonseca, Nanci Maria de França and Emmanuel Van Praagh
The purpose of the current study was to investigate the relationship between health-related physical fitness and bone mineral density (BMD) in adolescents. One hundred forty-four adolescents (65 boys and 79 girls) between 15 and 18 years of age were recruited to this cross-sectional study. Subjects were evaluated in aerobic fitness, muscular fitness, flexibility, body composition, and maturation. BMD of the lumbar spine, total body, and proximal femur were measured by a dual-energy X-ray absorptionmeter. Pearson’s correlation and stepwise multiple regression analyses were used (p < .05). Lean body mass (LBM) and abdominal muscular fitness explained 35–40% of proximal femur BMD in whole group and boys’ total body BMD (43%); however, VO2max and LBM predicted girls’ total body BMD (23%). Lumbar spine BMD was predicted only by LBM for both genders (18% boys, 15% girls). In summary, lean body mass is the main predictor of bone mass during the end of adolescence, regardless of gender, whereas muscular fitness contributes more to bone mass among males than among females.