Adaptive Randomization of Aerobic Exercise During Chemotherapy in Colon Cancer

This trial is studying how aerobic exercise — such as walking, cycling, or swimming — affects cancer treatment outcomes and quality of life in people with stage II or III colon cancer who are about to start chemotherapy after surgery. The exercise program is personalized and gradually increased over time. **You may be eligible if...** - You are 18 or older with confirmed stage II or III colon cancer - You have had surgery to remove the cancer and are planning to start chemotherapy - You currently exercise less than 60 minutes per week at moderate or vigorous intensity - You are physically able to walk 400 meters and are cleared to exercise - You can read and speak English **You may NOT be eligible if...** - You exercise more than 60 minutes per week already at moderate intensity - You have a major surgery planned during the study period - You have significant physical limitations that prevent safe exercise Talk to your doctor to see if this trial is right for you.