In a patient with morbid obesity and knee pain, which exercise is least appropriate?

• A. Step aerobics
• B. Weight-lifting program
• C. Aquatic exercises
• D. Stationary bicycling

Answer: (A)

In someone with morbid obesity and knee pain, the aim is to improve fitness while keeping knee stress low. Step aerobics involves repeated stepping onto and off of a raised platform and often includes jumping or fast transitions, which greatly increase impact forces on the knee joints. This higher load can worsen pain, accelerate joint wear, and hinder safe exercise in this situation. Aquatic exercises reduce joint compressive forces through buoyancy, making movement easier on the knees. Stationary cycling provides a smooth, low-impact way to build endurance and knee range of motion, and a properly supervised weight-lifting program can strengthen the muscles around the knee to improve stability. Because of the high impact and knee stress, step aerobics is the least appropriate choice here.