## 3 Results  
Table 1 established the descriptive results of the study. Mean values were obtained for adherence to the Mediterranean diet of M = 8.20 \(\pm\) 1.93, with 50.6% (\(n\) = 584) having a medium adherence, while 20.5% (\(n\) = 236) had a low adherence. In this sense, the problematic use of videogames showed a mean value of M = 1.31 \(\pm\) 0.34, which means that 81.3% (938) had no problems, while 15.5% (202) presented potential problems. The students obtained a mean value of M = 81.84 \(\pm\) 46.18 min of physical-sports activity per week and results of M = 10.16 \(\pm\) 0.60 with respect to hours of sleep per day. Finally, self-concept showed values of M = 4.17 \(\pm\) 0.32, with the highest values for family self-concept (M = 4.68 \(\pm\) 0.31) and academic self-concept (M = 4.30 \(\pm\) 0.49), and the lowest for social self-concept (M = 3.51 \(\pm\) 0.67). The general model developed by evaluating the variables that were measured in the sample of primary-school students according to gender showed a good fit for all the indices. The chi-square analysis showed significant values (X\({}^{2}\) = 0.159; \(p\) \(<\) 0.001; df = 1; pl = 0.691), but these indicators cannot be interpreted in isolation because they are sensitive to sample size; therefore, other standardized indices must be taken into account. The NFI showed a value of 0.998, the CFI obtained a value of 0.995, the IFI presented a value of 0.998 and the TLI showed a value of 1.028, which shows an excellent fit of the model. In addition, the RMSEA obtained a value of 0.001, which reveals an excellent fit for this parameter. Next, Figure 2 and Table 1 show the regression weights and the estimated values of the parameters of the theoretical model of structural equations, for which statistically significant relationships were obtained at the \(p\) \(<\) 0.05 level. Sleep duration was positively associated with self-concept (\(p\) \(<\) 0.01; r = 0.270) and negatively with problematic use of videogames (\(p\) \(<\) 0.001; r = \(-\)0.485). Thus, the practice of physical activity was directly related to self-concept (\(p\) \(<\) 0.001; r = 0.441) and indirectly with the problematic use of videogames (\(p\) \(<\) 0.01; r = \(-\)0.264). Furthermore, the practice of physical activity and the duration of sleep had a direct and bidirectional influence on each other (\(p\) \(<\) 0.001; r = 0.295). However, it should be noted that self-concept had a direct effect on adherence \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Variables** & **Categories** & **\% (\(n\))** \\ \hline \multirow{3}{*}{Adherence to the Mediterranean diet} & Low & 20.5 (236) \\ \cline{2-3}  & Medium & 50.6 (584) \\ \cline{2-3}  & \multicolumn{2}{c}{Hight} & 28.9 (334) \\ \hline \multirow{3}{*}{Problematic use of videogames} & No problems & 81.3 (938) \\ \cline{2-3}  & Potential problems & 15.5 (202) \\ \cline{2-3}  & Severe problems & 1.2 (14) \\ \hline \multirow{3}{*}{Minutes of physical activity (weekly)} & Minimum & Maximum & Mean & SD \\ \hline Minutes of physical activity (weekly) & 0 & 240 & 81.84 & 46.18 \\ \hline Hours of sleep & 8.00 & 11.80 & 10.16 & 0.60 \\ \hline Adherence to the Mediterranean diet & 5.00 & 12.00 & 8.20 & 1.93 \\ \hline Self-concept & 3.20 & 4.80 & 4.17 & 0.32 \\ \hline Academic self-concept & 2.76 & 5.00 & 4.30 & 0.49 \\ \hline Social self-concept & 2.33 & 5.00 & 4.23 & 0.58 \\ \hline Emotional self-concept & 1.33 & 5.00 & 3.51 & 0.67 \\ \hline Family self-concept & 3.83 & 5.00 & 4.68 & 0.31 \\ \hline Physical self-concept & 2.80 & 5.00 & 4.16 & 0.52 \\ \hline Problematic videogame use & 1.00 & 3.06 & 1.31 & 0.34 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Descriptive results of the study variables. to a Mediterranean diet (\(p<0.05\); r = 0.258) and an indirect effect on problematic use with videogames (\(p<0.001\); r = \(-0.394\)). The model developed for the male gender showed a good fit for all the indices. The chi-square analysis showed significant values (X\({}^{2}\) = 0.227; \(p<0.001\); df = 1; pl = 0.634).