How to Fix It: First, it's important to recognize why you are experiencing pain. Be sure that you are performing your squats and lunges properly, and running with good form. But even if you are using proper technique, you may still experience pain. Why?
"Since we sit most of the day, the knee joint becomes affected and often the meniscus becomes compressed only from one side (posteriorly)," says Dr. Yoav Suprun, DPT, a McKenzie physical therapist at Sobe Spine in Miami Beach. "As a result, many people feel knee pain as they get up (or after squats or lunges) that actually improves as the knee is more extended (as in walking or in running)."
Dr. Suprun recommends trying this move (before you work out, or if you are feeling pain): Start seated on a chair, extend one leg out straight in front of you and lock your knee joint as hard as possible for 5 seconds. Do 5 sets of 5-second holds. You may need to turn the foot in or out a bit as you do this but start with the foot straight, Dr. Suprun says.