The relation between physical activity, fitness, and fatness in adolescents: A mediation analysis

Objectives To investigate the total, direct and mediated (by fatness) association of physical activity (PA) with fitness. Methods Body fat percentage (%Fat), maximal oxygen uptake (VO 2max ) and PA were measured directly in 18‐year‐olds ( n =202) and their association analyzed with a linear regression‐based mediation analysis after controlling for sex. Results The total association between PA and VO 2max was significant ( c =0.66, P <0.001) and was significantly mediated by %Fat ( ab =0.25, 95% CI: 0.04–0.49). The direct association was also significant ( ć =0.41, P <0.001). Conclusion Physical activity is associated with VO 2max in 18‐year‐old adolescents but a little over a third of that association is mediated by %Fat. Regardless of fatness, PA is important for fitness in this age group. Am. J. Hum. Biol. 28:584–586, 2016. © 2015 Wiley Periodicals, Inc.