Competencies for health-enhancing physical activity are associated with body mass: results of an updated data pooling across 18 samples

Objective

Although previous studies have illuminated associations between body mass and physical activity (PA), there have been scant insights regarding the physical, cognitive, and motivational determinants of PA in relationship to body mass. This study aimed to model courses of competencies for health-enhancing PA across the spectrum of BMI.

Methods

We used cross-sectional data of 3670 individuals (mean [SD]: BMI, 25.54 [5.71] kg/m²; age, 46.11 [14.96] years) from a large data pooling with 18 primary samples employing the PA-related health competence (PAHCO) instrument. ANCOVA determined differences in 10 PAHCO indicators by BMI categories (underweight, normal weight, overweight, and obesity). Covariate-adjusted multilevel models described the nonlinear courses of the PAHCO indicators across the BMI spectrum.

Results

The levels of all 10 PAHCO indicators differed significantly among the BMI categories (F ≥ 14.8; p < 0.001). All competencies for health-enhancing PA could be best described by cubic functions having their maximum around normal weight while regressing with underweight and with increasing grades of obesity (0.02 ≤ $R_{m\arg }^2$ ≤ 0.31).

Conclusions

This study adds to associations between BMI and PA levels by specifying individuals' multidimensional requirements for health-enhancing PA. The present findings call for an integration of physical, motivational, and cognitive factors in practices of PA promotion and sustainable obesity treatment.