Effects of Aerobic Exercise on Skeletal Muscle Remodeling in Colorectal Cancer

This study is investigating whether aerobic exercise (like walking or cycling) can help preserve or rebuild muscle tissue in colorectal cancer survivors after completing treatment. Cancer treatment can cause significant muscle loss, and researchers want to understand how exercise affects muscle recovery at a biological level. **You may be eligible if...** - You are 18 or older - You have been diagnosed with stage I, II, or III colon or rectal cancer - You have completed surgery with curative intent and finished other cancer treatments - You currently exercise less than 150 minutes per week - You are willing to be randomly assigned to an exercise or control group **You may NOT be eligible if...** - Your cancer has spread or come back - You are currently being treated for another cancer - You are scheduled to receive more cancer treatment during the study period - You are pregnant, breastfeeding, or planning to become pregnant in the next 24 weeks - You have conditions that prevent you from doing MRI scans or aerobic exercise Talk to your doctor to see if this trial is right for you.