Physical activity does appear to reinforce adolescents’ body-esteem, particularly among boys. According to our study, the body-esteem was highest among adolescents who reported having been engaged in physical activity corresponding to the international recommendation for children and adolescents’ PA [21]. The positive effect of physical activity appeared as soon as there were more than two physically active days.
The positive effects of physical activity—such as improved physical endurance, mood, and self-esteem [28, 39, 40]—providing a feasible explanation for why the body-esteem of physically active participants was higher than that of physically inactive respondents. The effect may indicate a positive circle, with high body-esteem promoting physical activity, and vice versa. According to Kantanista et al. [10], a positive body image does indeed correlate with higher physical activity among 14- to 16-year-olds. In addition, among students aged from 12 to 17 years, physical activity has lately been found to improve body satisfaction and physical self-concept [41].
The higher body-esteem of boys was demonstrated here, in line with several previous studies [7–10]. For boys, physical activity had an independent positive impact on body-esteem, even when other determinants were taken into account. It should be noted that the link between physical activity and body-esteem depends on various factors, such as the amount and type of physical activity. However, our study highlighted a difference between genders as regards the connection between physical activity and body-esteem.
In addition to physical and mental qualities, the gender differences in the findings can be related to ideal body images that are gendered, and socially and culturally determined [2, 11]. Our findings correspond to the results by, for instance, Lawler and Nixon [42], according to which there is a statistically significant association between overweight and body dissatisfaction among 16-year-olds in both genders, but with a clearer association among girls. It seems that the pressures for slimness are particularly important for girls, and are thus more strongly linked to a negative body image [12]. Spencer et al. [43] concluded that girls’ relationships with PA are complex. This complexity arises, for example, in relation to notions of femininity, involving for example prevalent gender stereotyping in PA and the “femininity deficit”: girls are concerned about their appearance when they engage in PA. Nevertheless, girls enjoy PA, which they experience as offering enhanced self-esteem, social benefits, health, and satisfaction, as providing a creative outlet, and as allowing them to feel proud [43].
Previous studies have indicated that various factors influence adolescents’ PA, and do so in many different ways [28]. A national study revealed that for Finnish 13- and 15-year-olds the most important personal reasons for physical activity girls and boys in these age groups [44]. The most common reasons to be physically active were related to good feelings of trying one’s best, joy and play, health and fitness, and being together with friends. The desire to look good because of exercise increases in parallel with age during secondary school, but its significance seems to have decreased in Finland in recent years [44]. By contrast, every second 13-year-old mentioned prevention of obesity, or weight control. In addition, losing weight has been found to be a relatively common motive for adolescent girls [45–47]. In this context, it should be noted that exercise frequency is related to positive body image, but high levels of appearance-based exercise motivation might actually weaken the positive relationships between physical activity and higher body image among young women [48].
In our study, general self-esteem was by far the most significant factor determining body-esteem in both genders. Furnham et al. [49] have noted that (in contrast with boys), only girls associate body dissatisfaction with the concept of self-esteem. However, perceived body dissatisfaction arises from a complex interplay of factors, including gender, self‐esteem, and actual body mass [50]. According to our results, overweight and obesity were the only factors that lowered body-esteem in both genders. A recent study has obtained similar results [41]. It has also been noted previously that in Finland, dieting attempts among overweight and obese teenage boys became more common in the 2010s [45]. The findings by Galli et al. [51] have highlighted the pressures on male athletes related to appearance expectations. Taken together, the findings related to male adolescents may indicate the increasing prevalence of weight-related appearance pressures among men and boys.
The study has several strengths, the most important being the representative sample and high response rates. Since the sampling was meticulous and comprehensive, the results of this study can be generalized to 15-year-old pupils in Finland. The respondents answered the survey questions anonymously, and were supervised in school premises, making it possible to obtain confidential information from the adolescents themselves. The students had the opportunity to refuse to answer by leaving a blank form in a closed envelope. The aim was to minimize the influence of the group by emphasizing the voluntary nature of the survey, and the importance of honest, personal answers. The response rates were therefore high.
The fact that the results are based on information given by the adolescents themselves may raise questions concerning data reliability. With respect to inquiries on PA answered by adolescents, the repeatability has been found to be good [52], even though the reliability compared to objective indicators is, at best, moderate [53]. Prochaska et al. [35] note that the MVPA scale correlates somewhat weakly with objective PA results, but that it is a good and reliable indicator for surveys because of its repeatability. The reliability of the scale is also supported by other studies [54–56].
Another target of criticism has been the use of the BMI in determining weight status and obesity. According to prior research, the heights and weights reported by 15-year-old adolescents are sufficiently reliable for classifications based on the BMI in extensive surveys [57, 58]. However, particularly with regard to boys who engage in sports, the critique is based on the fact that the BMI does not indicate the proportion of muscles that are heavier than fat. We would accept that exceptional cases do exist, but that our findings are broadly sound, being based on an extensive, nationally representative sample of the entire age group.
Some of the original BESAA statements had to be omitted because of limits to questionnaire length of this study. The statements in the abbreviated version were selected from a complete BESAA scale that had been tested in a pilot study using statistical analyses. The internal consistency of the abbreviated version was high, and the distribution of the score was normal (Figures 1 and 2).
The cross-sectional design of our study makes it impossible to make conclusive inferences about causality based on the findings. A longitudinal study would permit more thorough research into the development of the phenomenon, and the potential gendered differences and mechanisms therein.