Most sports require a strong core region, making the squat a valuable addition to many athletes training programs. As a muscle-builder, squats - both the standard version and its variations - are unsurpassed for building leg size from all angles, and for working the physique systemically. Squats work all the muscles of the quadriceps (the rectus femoris - middle head- vastus lateralis - outer head - and vastus medialis - inner head) and hamstrings (the biceps femoris - outer head - semimembranosus - middle head - and semitendinosus - inner head), along with hip flexors and abductor (on the outer thighs) and adductors (on the inner thighs). Physically Demanding: The benefits of squatting do not end there. In addition to at least 75 percent of the body's muscle (primary ones being the shoulders, back, trapezius, gluteus maximus, and calves along with the thighs and hamstrings) being worked through the squat, it is the most physically demanding of the various weight training exercises, so will therefore enhance cardiovascular health and endurance levels. Metabolic & GH Stimulation: The squat, due to its intense nature, will also stimulate the metabolism greater than any other movement, which will assist with fat burning, both during the exercise itself and at rest. Also, of special interest to bodybuilders, and due to its degree of difficulty and strenuousness, is its ability to release higher amounts of growth hormone, which will contribute greater overall gains in muscle size and strength. Strength Enhancement: Lastly, the squat has been shown to enhance strength in all other lifts due to its ability to work a greater range of muscles, thus adding to its reputation as a total body developer. Standard Squats: Hailed as the king of all bodybuilding exercises, the front squat is known to add more total body mass than any other movement. As a leg mass-builder it is unparalleled, so should form a major part of any bodybuilders training arsenal. Preparation & Execution: Position bar in squat rack about three inches below the upper shoulder area. Place hands evenly spaced on the bar, and place bar comfortably across trapezius area. Push weight up using legs, not back. Walk weight out. Place legs at slightly wider the shoulder width with toes pointed sightly outward. Keep head up and chest out. Arch back. Slowly bend knees while keeping hips under the bar and torso erect (do not bend the back). Fully descend into a deep squat, while controlling the weight and keeping tension on the leg muscles. At bottom of movement, push bar up with feet and hips while breathing out forcefully. End at lockout and repeat (a non-lockout position can be used for one set of this exercise per workout).