Main results
We included four trials involving 94 participants in this review. There was a significant improvement in activity of daily living (mean difference (MD) 13.20 points on the 'Capacidad funcional' (functional capacity) subscale of the Brazilian-Portuguese version of the SF-36; 95% confidence interval (CI) 8.36 to 18.04; P < 0.00001) and on muscle strength (MD 1.01 Nm/kg; 95% CI 0.19 to 1.83; P = 0.02) but these results should be interpreted with caution because population numbers were small and the results are based on single studies. There was no significant improvement in ability to walk (MD 0.14 m/s; 95% CI -0.32 to 0.606; P = 0.55), postural balance (MD 3.05 points; 95% CI -3.41 to 9.52; P = 0.35) or fitness (MD 3.6 (VO2max; 95% CI -0.53 to 7.73; P = 0.09) after water-based exercises treatment compared to control. Adverse effects were not reported.