Abstract
BackgroundPhysical activity (PA) is suggested to contribute to fat loss not only through increasing energy expenditure “per se” but also increasing muscle mass; therefore, it would be interesting to better understand the specific associations of PA with the different body’s components such as fat mass and muscle mass. The aim of the present study was to examine the association between objectively measured PA and indices of fat mass and muscle components independently of each other giving, at the same time, gender-specific information in a wide cohort of European adolescents.MethodsA cross-sectional study in a school setting was conducted in 2200 (1016 males) adolescents (14.7 ±1.2 years). Weight, height, skinfold thickness, bioimpedance and PA (accelerometry) were measured. Indices of fat mass (body mass index, % fat mass, sum of skinfolds) and muscular component (assessed as fat-free mass) were calculated. Multiple regression analyses were performed adjusting for several confounders including fat-free mass and fat mass when possible.ResultsVigorous PA was positively associated with height (p < 0.05) in males, whilst, vigorous PA, moderate-vigorous PA and average PA were negatively associated with all the indices of fat mass (all p < 0.01) in both genders, except for average PA in relation with body mass index in females. Regarding muscular components, vigorous PA showed positive associations with fat-free mass and muscle mass (all p < 0.05) in both genders. Average PA was positively associated with fat-free mass (both p < 0.05) in males and females.ConclusionThe present study suggests that PA, especially vigorous PA, is negatively associated with indices of fat mass and positively associated with markers of muscle mass, after adjusting for several confounders (including indices of fat mass and muscle mass when possible). Future studies should focus not only on the classical relationship between PA and fat mass, but also on PA and muscular components, analyzing the independent role of both with the different PA intensities.
Highlights
Physical activity (PA) is suggested to contribute to fat loss through increasing energy expenditure “per se” and increasing muscle mass; it would be interesting to better understand the specific associations of PA with the different body’s components such as fat mass and muscle mass
It is well known that body mass index (BMI) is an indicator of fat mass and of lean mass, Metcalf et al studied the role of height in the associations of BMI and fat mass index (FMI) with several health markers in children aged 7 to 12 years [12]
The aim of the present study was to examine the association between objectively measured PA and indices of fat mass and fat-free mass (FFM) independently of each other giving, at the same time, gender-specific information in a wide cohort of European adolescents participating in the HELENA-CSS
Summary
Physical activity (PA) is suggested to contribute to fat loss through increasing energy expenditure “per se” and increasing muscle mass; it would be interesting to better understand the specific associations of PA with the different body’s components such as fat mass and muscle mass. It is well known that body mass index (BMI) is an indicator of fat mass and of lean mass, Metcalf et al studied the role of height in the associations of BMI and fat mass index (FMI) with several health markers in children aged 7 to 12 years [12] They concluded that indices of fat mass should take into account height as an important aspect when looking for relationships with health status [12]. None of the previous studies took into account the possible role of fat-free mass (FFM) as a marker of muscle mass in the association between PA and markers of fat mass
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