Cardiorespiratory fitness and muscular fitness correlates in youth: A hierarchy of behavioral, contextual, and health-related outcomes

ObjectivesDespite the health importance of identifying correlates of physical fitness (PF) in youth, no investigation to date has explored the influence of behavioral, health-related, and contextual correlates simultaneously. We investigated the hierarchical relationship of multiple modifiable correlates favoring or diminishing cardiorespiratory fitness (CRF) and muscular fitness (MF) in youth.DesignCross-sectional investigation.MethodIn a sample of 5174 children and adolescents, 31 correlates were hierarchized according to their impact on CRF and MF assessed using the FITESCOLA® fitness battery. A Chi-squared Automatic Interaction Detection approach was employed and measures of correlation and association were used to investigate the relationship between PF and correlates.ResultsIn children, body mass index (BMI) was the most relevant factor to discriminate between high and low CRF and MF of the upper, middle, and lower body. While BMI was more important than any other correlate to differentiate levels of upper and lower body MF during adolescence, specific characteristics of sports participation (type and amount) emerged as key factors to discriminate between high and low CRF and middle body MF. Other correlates, including the self-report of active recess time, active commuting to school, favorable neighborhood conditions, and limited time on screens and cellphones, were demonstrative of favorable levels of PF.ConclusionsBoth body composition and sports-related characteristics emerged as the two most relevant factors of PF in youth. Additional health benefits may be obtained from building supportive environments for sports and healthy exercise habits within the household and at different school education levels.