Rich and physically active: where are we talking from?

In the paper entitled ‘‘Effects of socioeconomic status (SES) on physical activity in adolescents: a systematic review of the evidence,’’ recently published at number 3 of the latest volume, Stalsberg and Pedersen (2010) revise in depth and synthesize a set of informations and elucidations about the idea of how the practice of regular physical exercise is influenced by SES. However, the challenge of scientific knowledge requires an overview regarding some crucial questions. The present text indeed seems to be a great opportunity to raise some important issues. Immediately, it might be necessary to show a certain relativity within the concept of physical activity used by the authors. The assumption adopted by the latest volume, Stalsberg and Pedersen (2010), many times along the paper, concerns physical activities as those practiced during leisure time. Nevertheless, it is reasonable to make a distinction between ‘‘physical activity,’’ as in any activity that results a greater energy expenditure than in a state of rest. On the other hand, ‘‘physical exercise’’ may be regarded as all planed, structured and repeated physical activity whose objective is the improvement and maintenance of one or more components of physical aptitude (Caspersen et al., 1985). Although, most importantly, the authors have emphasized the challenge of measuring the effects of regular physical exercise (and even physical activity), not only because there is no standard state-ofthe-art instrument for such measurement but also due to the problem faced when we try to confront different studies, for the diversity of instruments, the article corroborates the hypothesis that adolescents with higher SES are more physically active than those with lower SES. However, the revised analysis of results allows to verify that studies in which the association was positive had the practice of physical exercise (Stalsberg & Pedersen, 2010, table 2) as the ‘‘measure’’ utilized. The association was largely negative when the ‘‘measure’’ was physical activity (Stalsberg & Pedersen, 2010, table 3). Possibly, individuals of lower socioeconomic classes have less access to the practice of sports, sports clubs, gymnasiums, information, etc. Then again, this same group could be more susceptible to travel from home to school on foot or by bike, likewise other daily activities that demand physical effort. The study of Johnston et al. (2007), cited by the latest volume, Stalsberg and Pedersen (2010), demonstrates precisely that participation in sporting activities is more prevalent in individuals of higher socioeconomic classes, while traveling on foot or by bicycle is more frequent in lower socioeconomic classes. It is important to accentuate that in developing countries this is a tendency that probably occurs frequently, considering that it is not rare to find children and adolescents working, performing heavy domestic chores and studying far from home without adequate means of transportation. Still, it may be relevant to emphasize another important issue: wealthier adolescents are healthier because they practice physical exercises, or because their elevated SES allows them choices and opportunities not available for groups of lower SES? It is important to consider, finally, that someone’s choice is not only related to the symbolic capital that considers that a certain behavior leads to a correct lifestyle for those with a determined economical background. Thus, future studies should investigate these questions.