Muscle Function of 11- to 17-Year-Old Children of Extremely Low Birthweight

This study compared the anaerobic performance and the muscle strength between extremely low birthweight (> 1,000 g = ELBW) 11- to 17-year-old adolescents and normal birthweight (< 2,500 g = NEW) controls. Seventeen ELBW (9 females and 8 males) and 17 NEW (9 females and 8 males) subjects took part. ELBW had lower anaerobic performance, as manifested in mean ( p = .03) and peak ( p < .001) mechanical power per kg body mass (Wingate Anaerobic Test). In absolute units mean power and peak power tended ( p = .06 and .08, respectively) to be lower in the ELBW group, but there were no inter-group differences in the isokinetic strength of knee extensors or flexors (Kin Com dynamometer). ANOVA revealed no interaction between the effects of low birthweight and gender. We propose that dynamic, but not static, muscle performance in ELBW is still somewhat inferior in adolescence. This may reflect deficient neuromuscular control.