Objective To conduct a secondary analysis to study the effects that four months of aquatic resistance training has on self‐assessed symptoms and quality of life in postmenopausal women with mild knee osteoarthritis (OA), after the intervention and after a 12‐month follow‐up period.

Methods 87 postmenopausal volunteer women, aged 60–68 years, with mild knee OA were recruited in a randomised, controlled, 4‐month aquatic training trial (RCT) and randomly assigned to an intervention (n=43) and a control (n=44) group. The intervention group participated in 48 supervised aquatic resistance training sessions over four months while the control group maintained their usual level of physical activity. Additionally, 77 participants completed the 12‐month post‐intervention follow‐up period. Self‐assessed symptoms were estimated using the OA‐specific Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and Health‐related Quality of life (HRQoL) using the generic Short‐form Health Survey (SF‐36).

Results After four months of aquatic resistance training, there was a significant decrease in the stiffness dimension of WOMAC ‐8.5mm (95% CI= ‐14.9 to ‐2.0, p=0.006) in the training group compared to the controls. After the cessation of the training, this benefit was no longer observed during the 12‐month follow‐up. No between‐group differences were observed in any of the SF‐36 dimensions.

Conclusions The results of this study show that participation in an intensive aquatic resistance training program did not have any short‐ or long‐term impact on pain and physical function or quality of life in women with mild knee OA. However, a small short‐term decrease in knee stiffness was observed.