Which leg workout works best for aching knees?

This study tested which of two specific leg-strengthening exercises is more helpful for people with knee osteoarthritis. Twenty-four women with knee pain performed either 'eccentric' (muscle lengthening) or 'concentric' (muscle shortening) exercises three times a week for six weeks. Researchers measured changes in leg strength, knee flexibility, and how well participants could perform daily activities to determine which exercise approach provided better relief.