The knee joint is one of the most heavily used joints in the body. Any time that you are standing, walking, squatting, kneeling, or running, the knee joints are experiencing a significant amount of use and force. In fact, when you are simply walking, your knees experience up to 3 times your body weight just from teh impact of your foot hitting the ground. When you run, that force increases up to over 5 times your body weight. That means for a 150 pound person running, each of their knees will experience over 750 pounds of force with each step. This amount of force, combined with the amount of time that we spend throughout the course of our lives, makes the knee joints very susceptible to wear and tear. This wear and tear eventually causes pain, whether it is from tendonitis or arthritis. Maintaining the proper flexibility and strength of the muscles around your knee helps the knee to handle some of this excess force in a manner that reduces the liklihood of injury and pain. This is where a Physical Therapist is able to appropriately prescribe exercises and activities to keep teh right muscles strong and flexibile in the right places.