Light activities such as walking and swimming help strengthen muscles, keep ligaments and tendons flexible, prevent obesity and circulate blood to stiff joints. Keep them short but regular — 15-30 minutes of activities five days a week is a great start. Swimming is especially great for dogs with arthritis because the water supports much of the bodyweight and inhibits sudden excessive movements. Cats with arthritis, meanwhile, may not be as keen to get in the water but can participate in short sessions of gentle play. Just remember to avoid activities in which your dog or cat has to leap, jump, turn quickly or run. They can cause damage to your pet's joints.