Is There a Curvilinear Trajectory of Motor Competence Across Different Weight Status? Exploring the Non-Linear Hypothesis in Adolescents.

Background

Evidence supports that motor competence is inversely associated with weight status, yet less is known about this relationship among young people who are underweight. We hypothesized that there is a non-linear trajectory of motor competence across weight status categories (from underweight to obesity). Purpose: To check whether a non-liner relationship exists between motor competence and weight status in adolescents. Research

Design

Cross-sectional study. Study sample: we assessed the motor competence of 310 participants (44.8% boys), aged 12-15 years. Data Collection: Motor competence was assessed the Korperkoordinationstest für Kinder (KTK). Weight status (underweight, normal weight, overweight and obesity) was determined using body mass index (BMI).

Results

Motor competence was inversely associated with BMI in normal weight (rho = -.222, p = .001), overweight (rho = -.309, p = .028) and obesity (rho = -.663, p < .001), but not in underweight (rho = .193, p = .508). Adolescents with normal weight presented higher motor competence than those with overweight (mean difference = 17.198, p = .001) and obesity (mean difference = 31.686, p < .001). There was no significant difference in motor competence between normal weight and underweight categories. In addition, boys showed a curvilinear trajectory of motor competence, being ascendant from underweight to normal weight and then downward with increasing BMI. Polynomial regressions, fitting a non-linear model, confirmed a non-linear relationship between motor competence and BMI in boys (B = -3.534, p < .001).

Conclusions

Our findings suggest that the inverse relationship between motor competence and BMI does not occur in adolescents who are underweight. Furthermore, our results supported the non-linear hypothesis about the relationship between motor competence and weight status in boys.