Supine leg lifts generally do not injure the knee, but if you have a knee condition or if you overdo supine leg lifts, you may increase the risk of knee injury. Supine leg raising bends the knee and raises it toward the chest, which is good for exercising the abdominal and thigh muscles and enhancing the stability of the knee joint. When performed under proper guidance, supine leg raising does not usually injure the knee joint. If you have a knee joint disease, it is possible to further damage the joint if you accidentally cause a large impact on the joint during exercise. If the exercise is excessive and beyond the body’s tolerance, it may also cause knee injuries. Whether or not supine leg raising injures the knee depends on the specific situation. It is recommended to warm up fully before the supine leg raising, relax and rest after the exercise, and make gradual progress in the process, according to the amount of strength, so as not to cause bodily injury.