## 4 Discussion  
The findings of this study were rather unexpected. First and foremost, all associations determined between the PA modalities and QoL domains, whether they were statistically significant and positive or negative, were weak (less than 0.25). Furthermore, even the statistically significant associations differed from those established in previous research. Thus, no statistically significant associations were found between physical activity and physical health, contrary to the findings from earlier studies [14, 48]. The data would be more understandable if the respondents were young, but this was a sample of middle-aged individuals. On the other hand, all modalities of physical activity were positively associated with psychological health as a subdomain of quality of life, which is encouraging. Along with mental health, moderate PA was positively associated with the environmental health domain, while vigorous PA was negatively associated with social relationships (weak association). The lack of association between physical activity and environmental health is understandable, since this domain refers predominantly to (objective) socioeconomic parameters, which individual PA cannot influence. The fact that vigorous PA was negatively related to the domain of social relationships indicates that it is necessary to identify those activities and determine whether or not they are socially interactive in character (long lasting, individual in nature), which could not be determined by using the selected questionnaires. Both BMI as an objective assessment and BI as a subjective assessment of body status were positively related to physical health, which was consistent with the findings of previous studies [11, 21], but only BMI was associated with the psychological health domain. This association was expected--with the increase in obesity and a negative image of one's \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & & \multicolumn{3}{c}{**PA as a Moderator of Relationships between**} & \multicolumn{3}{c}{**PA as a Moderator of Relationships between**} \\  & **Variables** & \multicolumn{3}{c}{**BI and Social Relationships**} & \multicolumn{3}{c}{**BI and Environmental Health**} \\  & & **Beta** & **Sig.** & \(\mathbf{R^{2}}\) & **(sig \(\mathbf{\Delta R^{2}}\))** & **Sig.** & **Beta** & **Sig.** & \(\mathbf{R^{2}}\) & **(sig \(\mathbf{\Delta R^{2}}\))** & **Sig.** \\ \hline \multirow{2}{*}{**Model 1**} & The index of & & & & & & & & & \\  & dissatisfaction with BI & 0.061 & 0.407 & 0.004 & 0.407 & 0.037 & 0.615 & 0.001 & 0.615 \\  & The index of & & & & & & & & & \\  & dissatisfaction with BI & 0.067 & 0.353 & & & & 0.044 & 0.550 & & \\  & Walking & 0.042 & 0.574 & 0.078 & 0.005 & \(-\)0.002 & 0.978 & 0.024 & 0.350 \\  & Moderate PA & 0.146 & 0.060 & & & & 0.157 & 0.049 & (0.243) & 0.350 \\  & Vigorous PA & \(-\)0.305 & 0.000 & & & & \(-\)0.023 & 0.782 & & \\  & The index of & & & & & & & & & \\  & dissatisfaction with BI & \(-\)0.029 & 0.830 & & & \(-\)0.113 & 0.398 & & \\  & Walking & \(-\)0.198 & 0.137 & & & & \(-\)0.453 & 0.001 & & \\
**Model 3** & Moderate PA & 0.410 & 0.005 & 0.119 & 0.002 & 0.136 & 0.345 & 0.125 & \\  & Vigorous PA & \(-\)0.358 & 0.009 & (0.041) & 0.002 & 0.291 & 0.033 & (0.000) & 0.001 \\  & The index of & & & & & & & & \\  & dissatisfaction with & 0.312 & **0.035** & & & & & & \\  & BI x Walking & & & & & & & & \\  & The index of & & & & & & & & \\  & dissatisfaction with & \(-\)0.364 & **0.032** & & & 0.031 & 0.855 & & \\  & BI x Moderate PA & & & & & & & & \\  & The index of & & & & & & & & \\  & dissatisfaction with & 0.150 & 0.356 & & & \(-\)0.394 & **0.016** & & \\  & BI x Vigorous PA & & & & & & & & \\ \hline \hline \end{tabular}  
* **Legend: PA—physical activity, BI—body image, Beta—standard partial regression coefficient of each predictor variable on the criterion, Sig.—level of significance, R\({}^{2}\)—coefficient of multiple determination of the variable and predictor system.**  
\end{table}