Barbell Lunges

Rest the barbell on the back of your shoulders behind your neck, gripping it out near the plates.
 
With your feet about 8 inches apart and your toes pointing straight ahead, step forward about 2 to 3 feet with your right leg.
 
Bend your right leg and lower your body until your left knee is about 3-4 inches from the ground, keeping the natural curve of your spine by tensing your abdominal and lower back muscles; your right knee should be about 3-4 inches in front of your right ankle.
 
Straighten your right leg and return to the starting position; repeat with the opposite leg.
 
The entire motion should be done in a smooth, controlled manner that lasts about 4 seconds, with the downward movement no faster than the upward