Based on the Social Cognitive Theory, self efficacy strategies were employed to develop the intervention program and to promote regular exercise behavior (Figure I). All strategies were provided every sessions of the intervention. The process of the intervention and data collection were described in Figure 2. After baseline assessment, a session of general information •regarding osteoarthritis of the knee was provided to all participants and members in each elderly club participating in the study. This session consisted of definition of the disease, signs and symptoms, risk factors, treatments and pain management, exercise principles, and precautions regarding increasing pressure on knee joints. In addition, a booklet written by Wattana 3• was provided individually to each participant in both groups. The experimental group received the 12-week community-based exercise program whereas the control group did not. Based on the self-efficacy strategies, 24 bi-weekly group sessions were provided to the experimental group by the researcher. Beginning from the enactive mastery experience, each session began with a group discussion regarding osteoarthritis of the knee and exercise principles for people with osteoarthritis of the knee. Then, the stationary cycling exercise was performed as demonstrated. The exercise consisted of a 5 minute warm-up, 15 minutes of stationary cycling exercise, beginning with low and progress to moderate intensity of leg exercise at participants' own pace, and 10 minutes cool-down and stretching. After the exercise, a short additional group discussion was conducted by the researcher