Background and Aim: Knee osteoarthritis is one of the most common musculo-skeletal problems and can effect on patient's daily activity and produce dependency in their daily activity and functional disability such as including the balance of these patients. Therefore, the aim of this research is to investigate the effect of a period of therapeutic exercise and detraining after that on balance in the women with knee OA.

Materials and Methods: This research was a semi-empirical and applied on 24 inactive female patients with osteoarthritis of the knee with a physician's diagnosis and entering in Research. Subjects randomly classified into two groups, the therapeutic exercise and control. The Biodex Balance machine was used to determine static and dynamic balance in patients with pre-test and post-test in order to stabilize the situation and jeopardize. After pre-test in order to evaluate the durability of training, the tests were repeated after one months of detraining experimental group subjects. The therapeutic exercise protocols executed on subjects over 20 sessions (4 weeks and duration of each session about 60 minutes). During this time, the control group did not do any practice. The raw data was analyzed by SPSS version19. Friedman test and wilcoxon were used.

Results: Application of one course of treatment on the static balance: the overall stability and also dynamic balance of women with knee OA was significantly affected of (P ≤ 0/05). Also, one month detraining after of the training period showed lasting improvement of balance (static-dynamic).

Conclusion: Based on the results of the present research, execution of period of 4 weeks in therapeutic exercise can significantly effect on balance improvement in women with knee OA. This change will be stable after one month of detraining. Therefore, therapeutic exercise even in a short period of 4 weeks can be advised to be effective way to cure and improve balance in patients.

Key words: Therapeutic Exercise, Detraining, Balance, Knee Osteoarthritis