Fortunately, strengthening your quadriceps (the muscles on the fronts of the thighs) changes the equation, and so does losing weight. Each pound you lose reduces knee pressure in every step you take. One study found that the risk of developing osteoarthritis dropped 50% with each 11-pound weight loss among younger obese women. If older men lost enough weight to shift from an obese classification to just overweight — that is, from a body mass index (BMI) of 30 or higher down to one that fell between 25 and 29.9 — the researchers estimated knee osteoarthritis would decrease by a fifth. For older women, that shift would cut knee osteoarthritis by a third.