Let swelling and pain be your guides. Pain is an indicator that something isn't right. You may feel some discomfort with your exercises, but it should be "reasonable" discomfort. If you end up feeling a lot of pain that lasts more than one hour after exercise, you're probably overdoing it. If you have pain with exercise or activity, you need to make some changes. Reduce the intensity, time, or repetitions of your exercise or activity. If you see swelling around your knee late in the day, this could also be a sign that you are overdoing it.