Background Patients with Rheumatoid Arthritis (RA) can participate in regular physical activity (PA) without disease aggravation and accrue health benefits, including enhanced physical and psychological health . However, Self-determination Theory  proposes that the reasons why we participate in PA may determine the extent to which beneficial outcomes from PA can be accrued. Specifically, the benefits associated with PA participation will be maximised when one participates for autonomous reasons (i.e., enjoyment or personally valuing the benefits of PA) rather than for controlled reasons (i.e., because a health professional has told you to) .
Objectives To test whether reasons for participating in PA (motivation) explains variability in reported physical function and psychological health (subjective vitality and depressive symptoms) in addition to that of self-reported moderate to vigorous physical activity (MVPA).
Methods One hundred and six RA patients (Mage 54.5±12.3 years, 68% female, BMI = 28.10±5.80 kg/m2) completed the following questionnaires before entering a PA intervention: International Physical Activity Questionnaire, Subjective Vitality Scale, Behavioural Regulation in Exercise Questionnaire-2, Hospital Anxiety and Depression Scales and Health Assessment Questionnaire. Multiple hierarchical regression analyses were conducted controlling for disease activity (C-reactive protein). MVPA was added in Step 1 of the regression and motivation added in Step 2.
Results Analyses revealed that MVPA (b=0.29; p=0.04) significantly predicted subjective vitality [F(2,93)=4.37; p=0.02], explaining 9% of the variance. When motivation for participating in PA (b=0.27; p=0.006) was added, the model remained significant [F(3,92)=5.5; p=0.002] and explained an additional 7% of the variance. MVPA did not predict depressive symptoms [F(2,99)=2.8; p=0.07] but motivation was significantly and negatively related to reported depression [b= -0.30; p=0.01; F(3,98)=5.54; p=0.001], explaining 9% of the variance. MVPA did not significantly predict physical function [F(2,94)=1.65; p=0.20] but motivation was significant [b=0.2.60; p=0.009;] and explained 7% of the variance.
Conclusions More autonomous motivations for participating in PA were associated with a range of improvements in both physical and psychological health outcomes. Future PA promotion interventions in RA patients could maximise treatment benefits, such as improvements in physical function and feelings of vitality as well as reductions in depressive symptoms. This could be achieved by increasing enjoyment of PA and awareness of the benefits associated with this important health behaviour.
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Acknowledgements Medical Research Council and NPRI
Disclosure of Interest None declared