1. Place the bar atop your shoulders, spread your feet wide (pointing your toes in the same direction as your knees).

2. Inhale and lower your body until your thighs are approximately parallel to the floor.

3. Stand and return to starting position, exhaling at the top of the movement. Repeat the next repetition.

Notes: The primary muscles involved in this exercise are the quadriceps, all adductors (adductor longus, adductor magnus, adductor brevis, pectineus and gracilis), the gluteals, the hamstring group, and the sacrospinalis muscles.

2. Lower the safety bars holding the weighted platform in place and press the platform all the way up until your legs are fully extended in front of you. Make sure that you do not lock your knees. Your torso and the legs should make a perfect 90-degree angle. This will be your starting position.

3. Inhale and slowly lower the platform until your upper and lower legs make a 90-degree angle.

4. Pushing mainly with the heels of your feet and using the quadriceps go back to the starting position as you exhale. Repeat for subsequent repetitions and ensure to lock the safety pins properly once you are done to avoid the platform falling on you fully loaded.

WARNING! Always check to make sure that when you re-rack the weight the platform is securely locked.

Variations: All foot stance variations described in the foot stance section.

1. Inhale and raise your legs until they are almost parallel to the floor. Do not hold for resistance. If you wish more resistance, simple add more weight.

2. Exhale as you lower your legs to the starting position and complete the movement. Perform the next repetition.

Notes: This is the premier quadriceps isolation movement. For a greater resistance and more intense workout, incline the back of the seat to tilt your pelvis backward. The rectus femoris will then be stretched and be more intensely worked as you raise your legs.

This exercise is excellent for beginners for building a good strength foundation before trying more technical movements.

1. Inhale, rotate the stop handles on the sides of the shoulder pads to release the machine or sled, and bend your legs.

2. Lower the sled until your legs make a perfect “L” shape and so that your knee does not protrude past your toes.

3. Return to the starting position, exhaling as you complete the movement and perform the next repetition.

Notes: If you do not have a hack-squat machine at your gym, you can replace this exercise with combinations of dumbbell and front squat exercises.

This exercise places primary emphasis on the quadriceps. Adjusting the width of your feet changes the emphasis of muscles worked. For example, if you place your feet close together, you will place more emphasis on the gluteals; if you spread your feet, you will shift the work to the adductors.

To protect your back from injury, be sure to contract your abdominals so that your back remains flat against the pad and so that you avoid swinging your pelvis and spine.

1. Looking straight ahead, inhale, slightly arch your back, and squat down.

2. Lower yourself until your thighs are parallel to the floor, straighten your legs and return to the starting position.

3. Exhale as you complete the movement then perform the next repetition.

Notes: This exercise places primary emphasis on the quadriceps and the gluteals.

Place a barbell on a squat rack and approach the bar. Duck beneath the bar and position it atop your shoulders on the trapezius, slightly above the posterior part of the deltoids.

1. Grasp the bar using a grip width just outside your shoulders and pull your elbows to the rear.

2. Inhale deeply (to maintain inthoracic pressure and preventing your lower back from rounding while at the bottom of the lift in the squat position or, more commonly, while you are in the hole. Slightly arch you back by rotating your pelvis forward.

3. Look straight ahead and lift the bar off the rack and move backward a comfortable distance to prevent the bar from touch the rack while moving into your squat.

4. Place your feet shoulder width apart, keeping your toes pointing forward or slightly angled outward. Be certain that your knees follow the same angle of your toes as you squat.

5. Slowly bend your knees and squat down with your back bent slightly forward, but keep your back straight to avoid injury.

6. Squat until your thighs are parallel to the floor, extend your legs and straighten your torso to return to the starting or upright position.

7. Exhale as you complete the movement then, begin the next repetition.

Notes: This exercise places primary emphasis on the quadriceps, gluteals, adductors, spinal erectors, abdominals, and hamstrings.

Stand facing the bar. Place your feet considerably wider than shoulder-width apart with you toes pointing outward at about a 30 to 45 degree angle. To get the most out of this exercise and avoid injury, ensure that your toes and knees are in the same alignment, i.e., pointed the same way while in the squatting position.

1. Flex your knees until your thighs are parallel to the floor.

2. Use an overhand grip on the bar – hands about shoulder-width apart. Keep your arms hanging straight down inside your knees.

3. Inhale and hold your breath to expand your diaphragm, thereby protecting your back. Arch your back a little, shoulders back. Contract your abdominals and straighten your legs, extending your torso to stand erect. Exhale at the top of the movement.

4. Return to starting position and begin next repetition. Make sure to stabilize the weight before beginning lift.

Notes: This exercise places primary emphasis on the quadriceps and adductors and secondary emphasis on the back.

If lifting heavy weight, wear a weight belt. Also, make sure you can control the weight properly before moving up or down. Do not attempt heavy weight with this exercise if you are inexperienced. Doing so will possibly injure the adductors or hips and interconnecting tissue, as well as the sacrum and the lumbar vertebrae.