The leg extension is a resistance weight training exercise that targets the quadriceps muscle in the legs. The exercise is done using a machine called the Leg Extension Machine. … The exercise consists of bending the leg at the knee and extending the legs, then lowering them back to the original position.
The leg extension is an isolation exercise that targets your quadriceps, the muscles on the front of your thigh. It is a simple movement, which occurs at only one joint — your knees. The leg extension strengthens your quadriceps. and if done correctly, is not hard on the knee joint.