The legs are the most under worked part of the body especially when bodybuilding. Many people concentrate only on working the upper body and ignore the legs. But having strong legs is very important and also helps create that bodybuilders physique along with a developed upper body.
Leg extensions work the top of the thighs and warm up the leg. From a seated position you extend your legs until you have straightened them. Pause for a second and squeeze your thigh to make a contraction before lowering your leg again. Do not swing and drop your leg, but as with most training exercises, keep the action very controlled.
The main leg building exercise is the leg press which develops the sides of the legs. You do this lying down and push a weight away from your with your legs. Remember to bring your legs down slowly and to stop just before your knees reach your body. As always, keep the action controlled. Do not bounce your legs when you push up away from your body and do not let your knees lock into position.
The hamstring curl works the back of the legs. Lying comfortably on your front, you curl your legs upwards towards your body, pulling a weight with them. Stop before your legs touch your body and pause for a second before slowly lowering the weight again. It is important to maintain tension in your leg muscles and to keep control.
The standard calf raise is done standing up. You push a weight down by stretching your calfs and pushing your heels down, then let the weight up again by pushing up to a tiptoe position. Do not use your thighs for this exercise.