Knee injuries are very common among athletes. There are many different types of injuries that can happen to the knee joint. Common injuries include Osgood-Schlatter disease, Larsen-Johansson disease, ACL tear, meniscus tear, runner's knee, OCD, etc. But why knee injuries are so common?! When I explain to athletes, coaches, and parents, I usually use this analogy "because the knee is in a triangle relationship with the hip and ankle". The knee joint is between the hip and ankle. The hip is important because the posterolateral muscles of the hip controls the knee motion in athletic movements such as jumping, cutting, etc. Past studies have shown that poor control of the knee in those movements may put athletes in more risk of injuries such as ACL tear. Also, it has shown that weak hip muscles are related to lower extremity injuries. The ankle/foot is also important because whatever ankle and foot do will affect what the rest of the body does. If they do not function well, it will affect your balance ability, your ability to absorb ground reaction force, and where the knee goes. Tight Achilles and calf muscles will affect how you do things such as squat. The mid-foot needs some stability. Low and high arch will affect the rest of your lower leg. Foot and ankle are very complex and there are a lot of things that can go wrong. Thus, if you want to keep the knee healthy, you will need the ankle/foot and hip to function in ways they are supposed to. But if you can keep the hips and ankles/feet happy, the knees will be more than likely happy (injury free).
