The lunge is a lower-body compound exercise that works the buttocks and thighs. It can be performed with free weights or with body weight only. Because its primary goal is increased muscle strength through the use of weight, the lunge is a weight resistance exercise, not a cardiovascular one, and should be incorporated into a routine as such.
The lunge is performed by standing with feet hip distance apart. Hands are placed on the hips as you take a deep step forward while keeping your back foot in place. With your back straight, bend the front knee until the thigh is parallel to the floor and the back knee almost but doesn't quite touch the floor. Straighten the legs to bring the body up again. Push off of the front foot to bring you back to the starting position.
The lunge engages several muscles in the thighs and buttocks. The primary muscles involved are the quadriceps in the front of the thigh. Synergist or assist muscles include the gluteus maximus, the adductor magnus, the soleus and the hamstrings. Stabilizers are found primarily in the back and buttocks.
When muscles are stressed through exercise or weightlifting, microtears form in the muscle fiber. These tears eventually heal into scars, which strengthen the muscle as well as add bulk to it. According to Dr. Tim Maggs of the Washington Running Report, muscles require 24 to 36 hours of recovery time for oxygen and blood flow to heal the injuries and for glycogen levels to be restored.
To maximize the results of the lunge and avoid injury, proper form must be utilized along with weight resistance, and you must follow a schedule that allows for recovery. To increase resistance, hold dumbbells or a barbell as you perform the exercise. Choose a heavy enough weight that you have difficulty completing the last repetition of your set with good form. Aim for one set of eight to 12 reps, done to failure, with each leg for maximum strengthening benefits. After you've completed your set, allow your body at least one full day of rest before doing another set of lunges.