Objective: To assess the effects of a 16-week progressive, individualized, high-intensity strength training program on muscle strength, pain, and function in patients with rheumatoid arthritis (RA).
Methods: Twenty-four RA patients (men, n = 5; women, n = 19) receiving infliximab participated in a randomized controlled trial. The strength training (ST) group (n = 16) participated in a supervised program 3 times per week, and the control (C) group (n = 8) continued with standard of care as overseen by their rheumatologist. Assessments were completed at baseline and at weeks 8 and 16. Strength was measured by 3 repetition maximum (3RM), isometric hand dynamometer, and isokinetic dynamometer. A 100-mm visual analogue scale was used to assess pain. Functional performance was derived from a timed 50-foot walk and the Health Assessment Questionnaire Disability Index.
Results: The mean percent increase in strength (3RM) for the ST group from baseline to week 16 was 46.1% +/- 31.6% (P < 0.01) (mean of all three 3RM exercises: hammer curl, leg press, and incline dumbbell press), with mean gains in strength up to 4 times that of baseline values reported in all strength training exercises (upper and lower body) performed during exercise sessions. On average, right-hand grip strength increased by 2.9 +/- 4.0 kg in the ST group, in comparison with a loss of 1.2 +/- 3.0 kg in the C group over 16 weeks. The ST group had a 53% reduction in pain, in comparison with almost no change in the C group. The ST group had a significant improvement in 50-foot walk time, with a mean reduction of -1.2 +/- 1.6 seconds, in comparison with the C group (mean increase of 0.8 +/- 1.0 seconds; P = 0.01) over the 16 weeks. There was a clinically important difference (predefined as mean change +/-0.25) in the Health Assessment Questionnaire Disability Index in the ST group (-0.4 +/- 0.4) but not in the C group (-0.1 +/- 0.4).
Conclusion: High-intensity strength training in RA patients with varying levels of disease activity and joint damage had a large, significant effect on strength, and led to improvements in pain and function, with additive patient benefits beyond the effect of their infliximab use.