This page on leg exercise begins with the anatomy of the leg muscles so you know exactly what you are working out. Below is the quadricep, the muscles at the front of the thigh which act as extensors of the leg. The quads as extensors means they extend the leg outwards from the knee joint.
The four muscles involved are the rectus femoris, the vastus intermedius (these two muscles making up the central V-shape delineation of the middle front thigh), the vastus medialis of the inner thigh, and the vastus lateralis of the outer thigh.
The primary use of the quadriceps is to extend and straighten the leg.
If you want to know how to build quality thighs, see this webpage for building thighs that wins contests.
Below are the muscles of the hamstring, mainly the biceps femoris and associated muscles. The biceps femoris are the thigh flexors at the rear of the leg. As you can see, the anatomy of the hamstring is quite complex, there are a lot of muscles articulating. Biceps is latin for two-headed or having two parts. Femoris is latin for femur, so biceps femoris can mean two-headed femur from a latin to english translation.
Note: If you are pursuing bodybuilding or are interested in bodybuilding, check out this webpage on the importance of leg training, otherwise, scroll down to see specific leg exercises. To learn about the importance of hamstring development for bodybuilding, click here.
Purpose: To build mass and strength in the legs, especially the thighs. Full Squats are one of the traditional mass-building exercises for the entire lower body but are primarily for developing all four heads of the quadriceps.
Execution: 1) With the barbell on a rack, step under it so that it rests across the back of your shoulders, hold on to the bar to balance it, raise up to lift it off the rack, and step away. The movement can be done with your feet flat on the floor or your heels resting on a low block for support. 2) Keeping your head up and back straight, bend your knees and lower yourself until your thighs are just lower than parallel to the floor. From this point, push yourself back up to the starting position. See the diagram below for more on proper squatting form.
It is important to go below parallel in this movement, especially when you are just learning the exercise, so that you develop strength along the entire range of motion. If you don't go low enough in the beginning, you could injure yourself later when using heavier weight. Foot position to some extent determines which area of the thighs you work the most while doing Squats: A wider stance works the inside of the thighs to a greater degree, while a narrower stance tends to work the outside more; toes turning out hits the inside of the thighs. The basic stance for greatest power is usually feet shoulder-width apart, with toes turned slightly out.
Purpose: To develop extra mass and power in the thighs.
Execution: This exercise is done the way way as regular Squats except you go only halfway down. which will allow you to use heavier weight.
Purpose: To develop the quadriceps. When you do Squats on a machine, you can work the thighs a lot while placing less of a burden on other areas such as the knees and lower back. There are a number of machines designed to approximate the Squat movement. They use a variety of techniques to create resistance, including weights, friction, and even air compression.
Execution: 1) Place your shoulders under the bar and come up to a standing position. Position your feet to obtain the desired effects from the exercise. See here to know how to position your feet in effect to the muscle trained. 2) Bend your knees and squat down until your thighs are lower than parallel, then press back up to the starting position.
Turning your toes out helps develop the inside of the thighs. Balancing a barbel in this position could be difficult, but the machine makes it easy. Standing with your feet moved forward helps isolate the quadriceps, especially the lower area near the knee, and minimizes strain to the lower back since you don't need to bend forward at all.
Page 2 of leg exercises