BACKGROUND An up-to-date overview of the effectiveness and safety of dynamic exercise therapy (exercise therapy with a sufficient intensity, duration, and frequency to establish improvement in aerobic capacity and/or muscle strength) is lacking. OBJECTIVE To assess the effectiveness and safety of short-term (< three months) and long-term (> three months) dynamic exercise therapy programs (aerobic capacity and/or muscle strength training), either land or water-based, for people with RA. To do this we updated a previous Cochrane review (van den Ende 1998) and made categories for the different forms of dynamic exercise programs. METHODS A literature search (to December 2008) within various databases was performed in order to identify randomised controlled trials (RCTs). METHODS RCTs that included an exercise program fulfilling the following criteria were selected: a) frequency at least twice weekly for > 20 minutes; b) duration > 6 weeks; c) aerobic exercise intensity > 55% of the maximum heart rate and/or muscle strengthening exercises starting at 30% to 50% of one repetition maximum; and d) performed under supervision. Moreover, the RCT included one or more of the following outcome measures: functional ability, aerobic capacity, muscle strength, pain, disease activity or radiological damage. METHODS Two review authors independently selected eligible studies, rated the methodological quality, and extracted data. A qualitative analysis (best-evidence synthesis) was performed and, where appropriate, a quantitative data analysis (pooled effect sizes). RESULTS In total, eight studies were included in this updated review (two additional studies). Four of the eight studies fulfilled at least 8/10 methodological criteria. In this updated review four different dynamic exercise programs were found: (1) short-term, land-based aerobic capacity training, which results show moderate evidence for a positive effect on aerobic capacity (pooled effect size 0.99 (95% CI 0.29 to 1.68). (2) short-term, land-based aerobic capacity and muscle strength training, which results show moderate evidence for a positive effect on aerobic capacity and muscle strength (pooled effect size 0.47 (95% CI 0.01 to 0.93). (3) short-term, water-based aerobic capacity training, which results show limited evidence for a positive effect on functional ability and aerobic capacity. (4) long-term, land-based aerobic capacity and muscle strength training, which results show moderate evidence for a positive effect on aerobic capacity and muscle strength. With respect to safety, no deleterious effects were found in any of the included studies. CONCLUSIONS Based on the evidence, aerobic capacity training combined with muscle strength training is recommended as routine practice in patients with RA.