Osteoarthritis develops in athletes and laborers because injuries they incur on the field or the job WEAR DOWN the cartilage in their joints, triggering pain and, eventually, damage. So what injuries may lead to OA? The KNEE is most susceptible to injury AND OA. When tissue in the knee becomes torn it can lead to arthritis. For example, the anterior cruciate ligament, or ACL, connects the bones of your knee joint. It is often torn during sports that require twisting and pivoting. Even after surgical repair, the knee joint may be less stable and that increases the risk of OA down the road. ACL tears ALSO increase the risk of a MENISCUS tear. The meniscus, a disc-shaped pad of cartilage located across your knee, distributes force equally across the joint. When it's torn or a part is removed during surgery, there's less of it to absorb shock and pressure. A weakened meniscus decreases joint stability and leaves the knee more prone to further cartilage loss. ACL tears and MENISCAL tears combined COMPOUND the chance of knee osteoarthritis. OA of the HIP is something that may afflict people who FREQUENTLY climb stairs, CONSISTENTLY engage in heavy lifting, and participate in HIGH-intensity sports activity. Depending on the activity, people can develop femur head migration, joint edge tears, and general soft tissue damage. These all cause WEAKENED and unstable hip joints-all possible JUMPSTARTS to the arthritic process. The shoulder is also susceptible to OA when hit with repeated dislocations and rotator cuff injuries. AND, OA in the shoulder AND elbow can be traced back to trauma or repetitive movement. Finally, recurrent ANKLE sprains lead to joint instability, which, decades later, can progress to OA . So if you're athletic or enjoy exercising, or if your job requires heavy labor, make sure you STRENGTHEN the muscles surrounding your joints in an effort to avoid injury. To learn more about OA, watch additional videos in this series.