Sore knees? Give them a Bath. If you sit around in an office chair all day, your knee joints aren’t being lubricated. That can lead to knee pain. Try the quad pump, a 10-second exercise that causes your cartilage to secrete fluid, bathing the knee joint in nutrients to keep it healthy. Sit in a chair and extend your legs straight out so that your heels rest on the floor. Now tighten your quadriceps, the thigh muscles above your knees. Hold the contraction for 2 seconds then release. Repeat five times to squeeze lubrication into your knee joint. Feel better?