Associations of Motor Competence, Cardiorespiratory Fitness, and Physical Activity: The Mediating Role of Cardiorespiratory Fitness.

Purpose: Supporting children's physical activity (PA) behavior is imperative in order to safeguard their health. In an attempt to gain a deeper understanding about children's PA behavior, the aim of this study was to investigate the associations among motor competence (MC), cardiorespiratory fitness (CRF) and ambulatory PA during middle and late childhood. Method: A cross-sectional design was adopted and a total of 576 8-12-year-old children (M age  = 10.2 years, SD = 1.3) were examined. MC was assessed by the Canadian Agility and Movement Skill Assessment; daily PA (steps/day) was obtained by pedometers; CRF was measured by the Progressive Aerobic Cardiovascular Endurance Run. The associations among the key study variables were investigated by correlation and mediation analyses. Using a bootstrap method, two mediation models were tested: (a) MC predicting PA through CRF, (b) PA predicting MC through CRF. Results: MC, CRF, and PA present significant and positive associations both in boys and girls ( p < .05). CRF fully mediates the relationship between MC and PA in both directions [Model 1: b = .138, 95% CI (.0952, .1869), Model 2: b = .108, 95% CI (.0752, .1445)]. The pathway leading from PA to MC ( R 2   = .375, p < .0001) has stronger predictive utility than the reverse pathway ( R 2   = .124, p < .0001). Conclusion: MC and CRF are important predictors of children's PA participation; therefore, systematic and targeted interventions focused on the enhancement of these two factors should be used as a mechanism to reinforce children's PA behavior.