## 4 Discussion
Therefore, our findings suggest that feeling able to perform any physical exercise would dampen the effect of perceiving walking as intense and would help to successfully cope with fibromyalgia. Regarding the potential clinical applications of the present study, we believe that focusing solely on reducing pain intensity would be an inadequate therapeutic goal. From a rehabilitative perspective, the most effective treatments for fibromyalgia are those that combine cognitive-behavioral therapy with graded physical exercise for each patient profile [9; 54]. Following these guidelines, we consider it appropriate to work on promoting self-efficacy through motivational and volitional interventions that encourage a preference for achievement goals over hedonic goals based on pain/movement avoidance. Furthermore, our data tentatively suggest that a physical program is also effective with individuals in whom large differences exist between perceived intensity of physical exercise and target performance. This clinical approach makes sense if fear of injury is adequately addressed as a belief easily modifiable by ability; the minimization of such beliefs are also related to positive emotional states and to less symptom interference [76; 77]. Despite its possible implications, there are limitations to this study that warrant some attention. First, it might be expected that the female volunteers who participated in our study felt more confident in performing physical exercise compared to the general population with fibromyalgia. Therefore, it would be interesting for future studies to also control for the role of catastrophizing as a possible behavioral inhibitor, as pointed out by the previous literature [59; 78; 79; 80]. Another limitation is regarding the age of the participants, as the mean age was older than in other studies. A well-known age-associated health problem is cognitive decline, which we assessed using a single question with responses distributed on a Likert-type scale. However, it is possible that a single self-report item is not a valid measure to detect the appearance of certain cognitive problems that could be influencing the proposed mediational model. For this reason, it is important to control for this health problem as a possible covariate, and to try to assess it with other appropriate instruments. Furthermore, it seems that the discordance between subjective and objective measures about physical exercise is higher in women than in men with fibromyalgia[51; 81], which in turn limits the generalization of the results obtained. Finally, our results indicate that the proposed model is not affected by the symptoms. However, symptoms such as fatigue have several dimensions that explain why this experience is unique to each patient [82]. Therefore, it would be important to assess physical fatigue and mental fatigue independently to explore their effect on this model. Along this line, we have included the effect of medication on the execution of physical activity and the perception of its intensity. Finally, as we have noted, women with FM tend to perceive greater activity and greater intensity than the exercise they have done. However, we do not know whether this result is confirmed in the healthy population. Therefore, we propose to resolve this question in future studies by replicating this model with the inclusion of a control group. In summary, previous research on chronic pain from motivational perspectives such as the goals-conflict theory [69], emphasize the role of adaptive cognitions to take into account during the multidisciplinary treatment of fibromyalgia. In this context, our results highlight the role of self-perceived capacity beliefs (self-efficacy), through adherence to walking, in mitigating patients' dysfunctionality within the rehabilitative context. Conceptualization, L.G., P.C., C.E., A.M.L.-P., D.C.-M., A.G.-A. and C.P. ; methodology, L.G., P.C. and C.P. ; formal analysis, L.G. and C.P. ; investigation, L.G., P.C., C.E., A.M.L.-P., D.C.-M., A.G.-A. and C.P.