“Strength training exercises and improves the ability of your muscles to do work by increasing the force they can exert (strength) and the length of time that they can exert that force (endurance). If you have arthritis, strength training is particularly important because strong, well-toned muscles and other supporting structures can help absorb the stress and strain placed on your joints. Weak muscles do just the opposite, forcing your joints to bear the brunt of impact, and encouraging joint misalignment and slippage.”
-Fox, Taylor, Yazdany (Arthritis For Dummies)