Physical Activity and Motor Competence Present a Positive Reciprocal Longitudinal Relationship Across Childhood and Early Adolescence

<jats:sec sec-type="background"><jats:title>Background:</jats:title><jats:p>The current study evaluated the reciprocal longitudinal relationship between physical activity (PA) and motor competence (MC) and the potential mediation of cardiorespiratory endurance across 7 years.</jats:p></jats:sec><jats:sec sec-type="methods"><jats:title>Methods:</jats:title><jats:p>This was a 7-year longitudinal study, the Copenhagen School Child Intervention Study (CoSCIS), with 3 measuring points [mean ages (in years) and respective sample size: 6.75 ± 0.37, n = 696; 9.59 ± 1.07, n = 617; 13.35 ± 0.34, n = 513]. PA was assessed using accelerometers. MC was evaluated by the <jats:italic>Körperkoordinationstest für Kinder</jats:italic> (KTK) test battery. Cardiorespiratory fitness (VO<jats:sub>2</jats:sub>peak) was evaluated using a continuous running protocol until exhaustion. Structural equation modeling was performed to evaluate the longitudinal associations.</jats:p></jats:sec><jats:sec sec-type="results"><jats:title>Results:</jats:title><jats:p>Vigorous PA (VPA) and MC presented reciprocal longitudinal association during the 7-year follow-up (VPA → MC; β = 0.18; 95% CI: 0.10, 0.26; MC → VPA; β = 0.14; 95% CI: 0.08, 0.21). In addition, VO<jats:sub>2</jats:sub>peak mediated the relationship in both directions (VPA → MC; β = 0.09; 95% CI: 0.06, 0.12; MC → VPA; β = 0.06; 95% CI: 0.03, 0.09).</jats:p></jats:sec><jats:sec sec-type="conclusions"><jats:title>Conclusions:</jats:title><jats:p>PA and MC presented a positive reciprocal relationship across childhood through early adolescence and VO<jats:sub>2</jats:sub>peak mediated the association in both directions. Interventions targeting to increase PA in children and adolescents should also address the development of MC skills because of the clear positive feedback loop between PA and MC.</jats:p></jats:sec>