Introduction: Low back pain is the first cause of disability in people under 45 years of age. Compared with healthy subjects, these people have instability in postural control and also a shortness of hamstrings, which can cause low back pain. The aim of this study was to investigate the effect of aquatic therapy on the postural control and hamstring flexibility in females with chronic low back pain.

Methods: This study was a quasi-experimental and subjects were 20- to 40-year-old females that had referred to Hamadan physiotherapy clinics. The Y balance test was used to measure postural control and AKE test was used to measure the length of the hamstring muscles. The TRN group performed aquatic exercises for 6 weeks, 3 days per week. Paired and independent t test was used to analyze the data and significance level was set at 0.05 (P ≤ 0.05).

Results: Paired t test showed that the training group had significantly improved after training in postural control and flexibility of their hamstring muscles (P ≤ 0.05), yet, in the control group, no significant improvement was indicated and the independent t test showed that there was a significant difference in the change of these variables in the two groups.

Conclusions: The aquatic therapy program used in this study improved postural control and increase hamstring flexibility, which is an important factor in low back pain. According to the results of this study, this program can probably be used in rehabilitation program of patients with low back pain to improve postural control and increase flexibility of the hamstring muscles.