Objective: To assess the effects of 12 months' dynamic strength training on muscle strength and bone mineral density (BMD) at the lumbar spine and femoral neck in patients with early rheumatoid arthritis (RA).
Methods: Thirty-two subjects in the training group (EG) and 33 in the control group (CG) completed the study. EG carried out strength training 2 times a week with moderate loads of 50-70% of repetition maximum. They were also encouraged to do recreational physical activities. CG performed recreational physical activities and range of motion exercises. Maximal strength of the knee extensors, trunk extensors and flexors, and grip strength were recorded with dynamometers. BMD was measured using dual x-ray absorptiometry. Modified Disease Activity Score, erythrocyte sedimentation rate, and pain were used for the estimation of disease activity, and Stanford Health Assessment Questionnaire to measure functional disability.
Results: The 12 month resistance training in EG led to statistically significant mean increases of 22-35% in all muscle groups examined. CG patients were also able to increase their strength to some degree (3-24%), but at the end of the study strengths in CG were significantly lower than in EG. By the end of the study lumbar spine BMD had changed by +0.19% (4.24) in EG and by -1.14% (4.36) in CG. The corresponding changes of femoral BMD were +1.10% (3.71) and -0.03% (3.58). The changes in BMD were minor and statistically not significant in both groups. However, femoral BMD was found to be decreased among those patients treated periodically with oral glucocorticoids (n = 15, 3 subjects from EG and 12 from CG) compared with changes in BMD among those not treated with systemic glucocorticoids (n = 50).
Conclusion: Minimally supervised strength training resulted in significant improvements in muscle strength without detrimental effects on disease activity. The detected annual changes in central BMD were minor and statistically insignificant in both groups. Special attention should be focused on those patients with RA with high disease activity and concomitant glucocorticoid treatment.