The aim of this study was to analyse the physical activity (PA) levels of regular athletes or non-athletes. In addition, the anthropometric characteristics were also compared. The main results revealed statistical differences in height and %fat mass between male athletes and non-athletes. Moreover, statistical differences were found in light PA of male participants and sedentary time, light PA and vigorous PA levels in female participants.
A recent study conducted in the Caucasian population in the Mediterranean area has revealed reference values of %FM between 13 and 20 % in men and 26.1 and 34.9 % for women between 20 and 29 years old (Coin et al. 2008). Our results revealed that male athletes (9.03–10.17 %FM), non-athlete men (10.81–12.33 %FM), female athletes (21.41–25.11) and non-athlete women (24.26–25.64) are below the reference values for this type of population.
The analysis of variance between male athletes and non-athletes revealed that on average, non-athletes were taller, heavier and had a greater percentage of fat mass and BMI. Nevertheless, statistical differences were only found in height and fat mass. Generally, athletes tended to have a lower percentage of fat mass and our results are in line with this idea (Katch et al. 2011; Whyte 2006). Such values can be justified by the greater recurrence of anaerobic and aerobic workouts that occur in the majority of sports, thus consuming more glycogen, carbohydrates and fat (Djelic et al. 2015). Evidence has also found that regular athletes tend to adapt their organism to an increase in energy from fat and to a decrease in energy from carbohydrates (Katch et al. 2011).
The statistical evidence found in the male participants was not confirmed in the female group. No statistical differences were found in anthropometric measures. Moreover, descriptive statistics showed that female non-athletes had a slightly larger fat mass than did athletes. Nevertheless, female athletes also had a slight greater BMI, although both were in line with healthy guidelines (Pescatello et al. 2014).
The absence of differences in fat mass between female athletes and non-athletes can be partially explained by the large amount of sedentary time spent by the athletes. In fact, the statistical differences between athletes and non-athletes in sedentary mode had no effect size, thus following a previous study that revealed that sedentary behaviour predicts some of the total and regional fatness in the female athletic population (Júdice et al. 2014).
Comparisons between male and female participants were also conducted in this study. Results revealed that male athletes and non-athletes were statistically taller, heavier and had a lower percentage of fat mass compared to female participants. These results are in line with previous studies that showed that women tend to be smaller, lighter and have a greater percentage of fat mass. The greater percentage of fat mass and the distribution of the fat by the body may be explained by the following reasons (Blaak 2001): (1) the catecholamine mediated leg free fatty acid release is lower in women compared to in men; (2) the free fatty acid release by the upper body subcutaneous fat depots is higher in men than in women; (3) there are some indications that basal fat oxidation is lower in females compared to males; and (4) postprandial fat storage may be higher in subcutaneous adipose tissue in women compared to in men.
The analysis of variance conducted in male participants revealed that athletes spend statistically more time in light PA than do non-athletes. No statistical differences were found in the remaining PA levels; nevertheless, a slightly greater average amount of time spent in vigorous activity and number of steps walked per day were found in athletes. On the other hand, non-athletes spent more time in sedentary mode and in moderate PA activities.
These pieces of evidence may lead to a thought that an athlete can be highly physically active but also can spend the rest of the day mostly in sedentary mode (Júdice et al. 2014). In fact, a study suggested that time spent in moderate-to-vigorous PA is unrelated with the time spent in sedentary mode (Craft et al. 2012). Moreover, a non-competitive athlete may ensure considerable levels of activity, and for that reason, the differences between both athletes and non-athletes can be mitigated. The comparison in female students revealed that athletes spent statistically more time in light PA and vigorous PA, as well as walked 1000 more steps per day on average, compared to non-athletes. On the other hand, non-athletes spent statistically more time in sedentary mode, although with no effect size. The minimum effect size values in all statistical differences may suggest that sports training may lead to an increase in time spent in activity but may not change the sedentary behaviour of both groups.
No statistical differences were found in PA levels between male and female athletes. Nevertheless, male non-athletes walked statistically more steps and spent statistically more time in moderate and vigorous PA levels than did female non-athletes. These results may suggest that sports may normalise the PA levels of athletes and non-competitive practice may lead to a gap between genders. This can be observed in previous studies in PA that suggested the existence of significant PA levels in male adults (Baptista et al. 2012; Bauman et al. 2009).
This study had some limitations that must be highlighted. The study design only considered athletes who are involved in three training sessions per week plus a weekly competition. For that reason, some participants classified as non-athletes may have engaged in regular physical activity in line with healthy guidelines. This limitation should be considered in future studies, particularly trying to organise three groups: athletes, non-athlete participants with regular physical activity practice and sedentary persons. It would also be interesting to analyse the sedentary patterns of athletes and track their physical activity patterns after the end of their athletic career.
The results obtained from this study may contribute to a better understanding of the PA reality in young adults. Generally, PA levels of both athlete and non-athlete participants are in line with healthy guidelines. Nevertheless, a gap between male and female non-athletes may suggest some specific behaviour that must be tracked over the course of years. Specific programmes aimed at non-athletes must be applied, mainly to promote the benefits of PA, as well as to engage non-athletes in regular PA activities over the week. In this field, special attention should be given to the female population, with attempts made to develop some activities that correspond to their expectations and aspirations.