Factors Affecting Naturally Occurring Change in Cardiorespiratory Fitness in Adolescent Females OverFour Years

Abstract

0072 PURPOSE: To determine the factors affecting change in cardiorespiratory fitness in middle school girls followed through high school. METHODS: Adolescent girls (N = 257, 61% African American, baseline age = 13.5±0.6 years) performed a submaximal fitness test (PWC-170) in 8th, 9th, and 12th grades. Height, weight, sports participation, and physical activity were also measured. Vigorous physical activity (VPA) was determined by the number of blocks reported on the 3-Day Physical Activity Recall (3DPAR), a validated self-report instrument. Individual differences and developmental change in fitness were assessed simultaneously by calculating individual growth curves for each participant using linear growth curve modeling. RESULTS: The model provided an overall slope and intercept for all participants. On average, girls lost 0.04 watts×kg−1×year-1 year in PWC-170 scores (P<0.01). The loss in PWC-170 scores was Modified by 8th grade participation in VPA and an interaction between race and sport participation (P≤0.05). Girls reporting one or more blocks of VPA at baseline showed an average increase in PWC-170 scores of 0.35 watts×kg−1×year-1 year. Among white girls, sport participants showed an average increase in PWC-170 scores of 0.34 watts×kg−1×year−1 year compared to non-participants. White sport participants had average increases in PWC-170 scores of 0.19 and 0.26 watts×kg−1×year-1 year compared to African American sport participants and non-participants, respectively. CONCLUSIONS: Although there were some fluctuations in PWC-170 scores across time, average PWC-170 scores decreased linearly over the course of four years. Vigorous physical activity and sport participation should be encouraged in adolescent girls in order to increase the likelihood of maintenance or improvement of cardiorespiratory fitness in the future. More research is necessary regarding the effect of the interaction of race and sport participation on cardiorespiratory fitness in adolescent girls. Supported by NHLBI RO1 HL057775.