Which type of exercise is appropriate to minimize joint stress in an obese patient with knee OA?

• A. High-impact running
• B. Step aerobics
• C. Non-weight-bearing aquatic exercise
• D. High-resistance cycling with heavy load

Answer: (C)

Minimizing joint stress while maintaining activity is best achieved by choosing movements that reduce knee loading. In obesity with knee OA, every step can transmit substantial forces through the joint, so high-impact and weight-bearing activities tend to aggravate pain and wear.

Non-weight-bearing aquatic exercise fits this goal because water buoyancy supports most of body weight, dramatically reducing knee compressive and shear forces with each movement. The joints stay protected while you can move through a full range of motion, and the water’s resistance provides a safe way to strengthen the muscles around the knee without grinding the joints. Hydrostatic pressure can also help with swelling, and the overall environment makes it easier to exercise regularly without pain flares.

In contrast, high-impact activities like running or step aerobics increase knee forces with each step, which can worsen symptoms. Even cycling with heavy resistance adds joint load through larger forces on the knee, so it’s less protective for someone with knee OA and obesity.