In weight training, a leg extension is a weight resistance exercise that targets muscles in the legs. Weight trainers use this exercise to target the quadriceps, which are muscles in the front part of the thighs. This exercise is performed in a seated position and using deliberate movements.
An individual may begin a leg extension by sitting on the seat of a leg extension machine. To perform this exercise properly, the exerciser has to position his body so the machine’s pads are over the top of his ankles and his back rests against the machine’s back pad. Sometimes this means the user has to adjust the machine to allow for proper positioning of the pad, especially if others have been using the machine. When seated and ready to begin the exercise, the user should make sure his knees are bent at a 90-degree angle; his knees should not extend out over his toes.
Once in the proper position for performing a leg extension, an individual should push his legs upward, extending them and straightening at the knee. He should use his quadriceps to perform this lifting motion. When he reaches the top of the lifting motion and his legs are straight, he should hold the position for a few seconds, keeping the quadriceps contracted as he does so.
The next step for a leg extension is to slowly lower the legs back to the starting position. The exerciser should inhale as he does this and work to keep the bend of his legs at a maximum 90-degree angle as he lowers them to help prevent excess stress on the knees and minimize the risk of injury. Sometimes the way a machine is designed causes an individual's legs to form less than a 90-degree angle in the starting or ending position. If this occurs, an exerciser may need to find a different machine in order to protect his knees and perform the exercise properly.
It’s important to make the movements of a leg extension slow and controlled. If an exerciser performs this exercise too fast or allows momentum to control his movements, the exercise's effectiveness may be diminished. If the exercise is performed too forcefully, injury may result. Additionally, it’s important to remember to consciously contract or squeeze the quadriceps muscles when the legs are lifted. This ensures the muscles are worked properly.