Gender and ethnic changes in physical work capacity from childhood through adolescence.

This study determined gender and ethnic differences in physical work capacity (PWC170) of 8-16-year-old American youth as they progress from elementary to high school. A multicohort group of 2,540 youth participated: 50.4 % girls (21.4 % African Americans, and 78.6 % Caucasians): PWC170 was predicted from cycle ergometer testing six times over a pear period. The absolute PWC170 of girls stabilized in early adolescence, while boys increased with each trial. The PWC170 relative to body weight of girls decreased steadily; whereas the boys remained stable: African Americans had greater absolute PWC170 values than. Caucasians (p = .0001). The relative PWC170 was lower for African American girls than Caucasian girls (p =. 0001), but there were no ethnic differences for boys (p >.05). Although correlations and grouping suggested moderate tracking, girls with high relative PWC170 tended to migrate to lower levels as they aged, where as high-performing boys maintained their PWC170 as they aged.