Quad Lift Machine

Do each exercise with smooth, controlled movements.

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You might know them as the thighs, but those large muscles at the top and front of your legs are technically known as the quadriceps. This group of four muscles - hence the "quad" terminology in the name - runs from above the knee to just below the hip region, helping with extension of the knees and flexion of the hips. If you have access to gym equipment, a few key machines will help you strengthen the quads and build additional muscle. Generally, there are two ways to work the quadriceps, including pressing the legs away from the trunk and extending the knee from flexed to extended.

Leg Press

Among the most common pieces of leg equipment you'll find at your gym is the leg press machine, sometimes called the sled press. With this machine, you sit in a seat that is tilted slightly backwards, wrap your hands around hand-holds near your hips and then place your feet on a platform that is positioned fairly perpendicular to the floor. This causes your legs to create an approximate 45-degree angle, with your knees at about eye level. You'll then press your legs forward, fully extending them. Since this machine recruits the quadriceps as well as the gluteus maximus of the butt - another large muscle - you'll probably find that you can lift a lot of weight with this machine.

Leg Extension

Another common piece of equipment at many gyms is the leg extension machine. This machine recruits only the quadriceps, so you'll likely find that you won't be able to lift as much weight as you would with the leg press. This machine may have a seat that positions you in an upright sitting position, or the seat may be tilted backward. In either case, sit on the seat and place your legs behind the padded lever, which will force your legs into a 45-degree angle. The lever should rest just above your feet on the lower part of the shins. Press your legs upward to create a long straight line between thigh and ankle; this should cause tension in the quadriceps.

Repetitions and Sets

Now that you know something about the two primary exercise machines for the quadriceps, it's time to develop a workout. Fortunately, it might not be as involved as you might think. According to Mayo Clinic's Dr. Edward Laskowski, one set of 12 to 15 repetitions of an exercise is enough to build muscle and improve your fitness level. One important addition is that you have to do that one set to fatigue, meaning your muscles will be so tired that it's difficult to finish the last few repetitions of the set. The key here is to pick the right amount of weight, which might take some trial-and-error. Start with a lighter weight and experiment; if it's not causing your legs to feel fatigued at the end of the set, move to a heavier weight the next time. Try doing the leg press and the leg extension two or three days a week, giving yourself at least 1 day of rest in between. Always do a warm-up of walking, cycling or some other light movement for 5 to 10 minutes to help prepare your body for the work ahead.

Additional Exercise

For the average person looking to gain some strength and build muscle, that one set of 12 to 15 repetitions is just fine. If you're an athlete or you're training for an event, you might benefit from doing even more. Instead of doing the same exercise in multiple sets, add some slight variety to your routine, which will recruit slightly different muscle fibers within the quadriceps muscles. For the leg press, move your legs up or down or further apart on the platform and perform one to three additional sets. For the leg extension machine, see if the machine allows you to change between an incline and straight-back seat.