Despite the fact that patients with arthritis are advised to exercise the front upper part of the leg, the quadriceps, a new study from Northwestern University found that strengthening the quadriceps produces a risk for people whose knees are unusually loose, or lax. The study results were published in the Annals of Internal Medicine (April 2003).
The researchers followed the conditions of ~230 arthritis patients over 18 months and found an association between quadriceps strengthening and a worsening of the disease. A conclusion from the study was that lax and misaligned knees do not properly distribute the load in exercise, and too much pressure is applied on vulnerable parts. Although the researchers are not advising patients with arthritis to avoid physical activity, they recommend that patients with misaligned or lax knees learn proper exercise tailored to specific muscles so that the benefits outweigh the risks.