BACKGROUND: Obesity, expressed as a high body mass index (BMI), is associated with a risk of decrease in functional capacity and muscle strength, in particular in weight-bearing joints, but so far, no study has been able to show a sufficiently strong relationship between these factors. two options in conclusion.AIM: This study was conducted to quantify the effect of intense exercise on the functional capacity and muscle power of obese individuals and the risk of knee osteoarthritis.MATERIALS AND METHODS: The present research project is characterized as a clinical trial, cross-sectional, and uncontrolled research. All participants had a body mass index from 30.6 kg/m² to 34.9 kg/m² and reported not working out in the last 3 months prior to this experiment. Before their involvement, all participants were informed during an initial interview about the experimental procedure, the nature of the research, and the test protocols. They gave their written and signed informed consent to voluntarily participate in this research and completed two questionnaires. Participants in our study were recruited from sports centers, social clubs, and word of mouth. A total of 78 participants responded to the call articipated in our training protocol which was composed of two main parts. The first one is the «Anthropometric measurements tests» and the second one is the «Functional capacity tests» that were done in a gym. The participants were divided randomly into two experimental. After the end of every phase of the experiment, some members of each group were moved randomly to the other group.RESULTS: The final results of the intra-class correlation coefficient measurements for a set of tests showed strong reliability among members of each examined group. For the handgrip strength tests of the right and left hands, the results were 0.850 and 0.892, respectively. For the squat jump and countermovement jump tests, the results were 0.966 and 0.932, respectively. The results were 0.896 and 0.945 for walking 6 meters with or without double tasks. Finally, for the TUG and TUP-DT tests, the results were 0.520 and 0.663, respectively. After analyzing and interpreting the data for the functional capacity tests, the following results were obtained: For the 5 sit-stand test, the result was (F (3.87)=4.22; p=0.008, ηp2=0.127). For the Time up and go test, the result was (F (3.87)=4.56; p=0.019, ηp2=0.136), and for the 6 m walk, the result was (F (3.87)=3.81; p=0.013, ηp2=0.116). Finally, the 5X sit-to-stand test at 48 hours was lower than the base value (p=0.024), while the TUG immediately after the post was lower than the base value.CONCLUSION: In conclusion, the results of this study demonstrate the positive impact of intense exercise on muscle power and functional capacity in obese individuals. These findings suggest that high-intensity physical activity may be an effective means of improving the health and quality of life of obese individuals. Therefore, it is recommended that obese individuals include high-intensity exercise in their regular exercise program to reap these health benefits. However, it is important to emphasize the importance of consulting a healthcare professional before starting a high-intensity exercise program to avoid the risk of injury or health complications.