Best Exercises to Build Quads

Squats

Barbell Squat

1. This exercise is best performed inside a squat rack for safety purposes. To begin, first set the bar on a rack to just below shoulder level. Once the correct height is chosen and the bar is loaded, step under the bar and place the back of your shoulders (slightly below the neck) across it.
2. Hold on to the bar using both arms at each side and lift it off the rack by first pushing with your legs and at the same time straightening your torso.
3. Step away from the rack and position your legs using a shoulder width medium stance with the toes slightly pointed out. Keep your head up at all times and also maintain a straight back. This will be your starting position. (Note: For the purposes of this discussion we will use the medium stance described above which targets overall development; however you can choose any of the three stances discussed in the foot stances section).
4. Begin to slowly lower the bar by bending the knees and hips as you maintain a straight posture with the head up. Continue down until the angle between the upper leg and the calves becomes slightly less than 90-degrees. Inhale as you perform this portion of the movement. Tip: If you performed the exercise correctly, the front of the knees should make an imaginary straight line with the toes that is perpendicular to the front. If your knees are past that imaginary line (if they are past your toes) then you are placing undue stress on the knee and the exercise has been performed incorrectly.
5. Begin to raise the bar as you exhale by pushing the floor with the heel of your foot as you straighten the legs again and go back to the starting position.
6. Repeat for the recommended amount of repetitions.

Caution: This is not an exercise to be taken lightly. If you have back issues, substitute it with the dumbbell squat variation or a leg press instead. If you have a healthy back, ensure perfect form and never slouch the back forward as this can cause back injury. Be cautious as well with the weight used; in case of doubt, use less weight rather than more. The squat is a very safe exercise but only if performed properly. See other great exercises for your legs below the lunges if you have lower back problems.

Lunges

1. Stand with your torso upright holding two dumbbells in your hands by your sides. This will be your starting position.
2. Step forward with your right leg around 2 feet or so from the foot being left stationary behind and lower your upper body down, while keeping the torso upright and maintaining balance. Inhale as you go down. Note: As in the other exercises, do not allow your knee to go forward beyond your toes as you come down, as this will put undue stress on the knee joint. Make sure that you keep your front shin perpendicular to the ground.
3. Using mainly the heel of your foot, push up and go back to the starting position as you exhale.
4. Repeat the movement for the recommended amount of repetitions and then perform with the left leg.

Caution: This is a movement that requires a great deal of balance so if you suffer from balance problems you may wish to either avoid it or just use your own bodyweight while holding on to a fixed object. Definitely never perform with a barbell on your back if you suffer from balance issues.

Variations: There are several ways to perform the exercise.

One way is to alternate each leg. For instance do one repetition with the right, then the left, then the right and so on.

The other way is to do what I call a static lunge where your starting position is with one of your feet already forward. In this case, you just go up and down from that starting position until you are done with the recommended amount of repetitions. Then you switch legs and do the same.

A more challenging version is the walking lunges where you walk across the room but in a lunging fashion. For walking lunges the leg being left back has to be brought forward after the lunging action has happened in order to continue moving ahead. This version is reserved for the most advanced athletes.

Lunges can be performed with dumbbells as described above or with a barbell on the back, though the barbell variety is better suited for the advanced athletes who have mastered the exercise and no longer have balance issues.

Leg Press Machine

1. Using a leg press machine, sit down on the machine and place your legs on the platform directly in front of you at a medium (shoulder width) foot stance. (Note: For the purposes of this discussion we will use the medium stance described above which targets overall development; however you can choose any of the three stances described in the foot positioning section).
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. Tip: 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. As you inhale, slowly lower the platform until your upper and lower legs make a 90-degree angle.
4. Pushing mainly with the ball of your foot and using the quadriceps go back to the starting position as you exhale.
5. Repeat for the recommended amount of repetitions and ensure to lock the safety pins properly once you are done. You do not want that platform falling on you fully loaded.

Caution: 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.

Hack Squat

1. Place the back of your torso against the back pad of the machine and hook your shoulders under the shoulder pads provided.
2. Position your legs in the platform using a shoulder width medium stance with the toes slightly pointed out. Tip: Keep your head up at all times and also maintain the back on the pad at all times.
3. Place your arms on the side handles of the machine and disengage the safety bars (which on most designs is done by moving the side handles from a facing front position to a diagonal position).
4. Now straighten your legs without locking the knees. This will be your starting position. (Note: For the purposes of this discussion we will use the medium stance described above which targets overall development; however you can choose any of the three stances described in the foot positioning section).
5. Begin to slowly lower the unit by bending the knees as you maintain a straight posture with the head up (back on the pad at all times). Continue down until the angle between the upper leg and the calves becomes slightly less than 90-degrees (which is the point in which the upper legs are below parallel to the floor). Inhale as you perform this portion of the movement. Tip: If you performed the exercise correctly, the front of the knees should make an imaginary straight line with the toes that is perpendicular to the front. If your knees are past that imaginary line (if they are past your toes) then you are placing undue stress on the knee and the exercise has been performed incorrectly.
6. Begin to raise the unit as you exhale by pushing the floor with mainly with the heel of your foot as you straighten the legs again and go back to the starting position.
7. Repeat for the recommended amount of repetitions.

Variations: All foot variations discussed in the foot positioning section apply.