Quad sets are one of those simple yet powerful exercises that can help you make the most of a period of recovery or rehab.

As with any exercise, quad sets should only be done with a doctor’s approval. But, chances are, if you’ve recently dealt with a knee injury or surgery, quad sets are in your future.

What Are Quad Sets?

“Quad sets, or total knee extensions (TKEs), are a great way to improve quad engagement, which can shut off after an injury or surgery,” says Carlos Teasdale, CSCS, founder of Low Back Solutions. “I use quad sets for anyone recovering from surgery or a serious knee injury.”

Teasdale explains that quad sets can help you regain your knee’s full range of motion, but a few guidelines apply.

Start slow and don’t push yourself past the point of muscle fatigue.

“By actively trying to squeeze the quad muscles to fully extend your knee, you will never be able to go past that natural range of motion that your capabilities allow you,” he says. “This natural limiter will prevent injury and improve results.”

Also, when you do quad sets matters. “[Quad sets] are not a good exercise to do before heavy squats, sprinting, or sports that involve cutting, jumping, or landing,” Teasdale says. “They will fatigue out the muscles that manage knee extension,” he explains, which leaves your knee susceptible to injury.

How to Do Quad Sets

Sit on a mat with your legs extended in front of you. Roll up a small towel and place it under your knee.
Use your quad muscles to fully straighten your leg and press the back of your knee into the towel. Hold the extension for three seconds, then release.
Complete three sets of 10 reps on the affected leg. However, if your quad muscle reaches full exhaustion before you complete 10 reps, stop, rest, and shorten your next set as needed.

More Quad Exercises

“Unlike most rehab movements, quad sets are not good to do outside of rehab,” Teasdale says, as they can fatigue the small muscles responsible for managing knee stability.

If you’re working with a pair of healthy, pain-free knees, here are some alternative quad exercises that can help you build quad strength.

1. Front to back lunge

Stand tall with your feet hip-width apart holding a pair of dumbbells at arm’s length by your sides.
Keeping your chest up and core engaged, take a large step forward with your right foot.
Lower your body until your right thigh is parallel with the floor and your left knee is bent about 90 degrees, just above the floor.
Pause, and then push off with your right foot, stepping back into a reverse lunge without returning to the starting position.
That’s one rep. Complete all of your reps, and then repeat with your left leg.

2. Banded squats

Loop a small resistance band around both legs just above your knees. Stand tall with your hands by your sides, feet shoulder-width apart, and toes pointed forward.
Keeping your back flat and core braced, push your hips back, bend your knees, and lower your body until your thighs are parallel to the floor.
Pause, and then push yourself back up to the starting position.

3. Walking lunges

Stand with your feet about hip-width apart and your hands on your hips.
With a stride that’s a little less than double your normal walking stride, bring your left leg forward and plant your left foot.
Come up on the ball of your right foot as you bend your left knee 90 degrees (or as low as you can comfortably go) and lower your right knee, allowing it to hover just above the ground. Your back knee should also be bent at a 90-degree angle.
With your weight on your left foot, push off your right foot and straighten your legs, bringing your right foot forward to meet your left foot as you return to a standing position.
Repeat on the opposite side, lunging forward with your right leg.
Continue to move forward, lunging with alternating legs, for the specified distance or number of steps.

4. Bulgarian split squats

Stand facing away from a bench, holding a pair of dumbbells at arm’s length by your sides. (If the Bulgarian split squat is a new movement for you, you may want to skip using the dumbbells.)
Place the toes of your left foot on the bench behind you.
Keeping your torso upright, lower your body until your right thigh is parallel to the ground and your left knee is hovering above the floor.
Pause, and then push back up to the starting position. Do equal reps on both legs.

5. Pistol squats

Stand with your back to a bench or other stable, knee-high platform, holding one dumbbell in front of your chest in both hands. (If the pistol squat is a new movement for you, you may want to skip using the dumbbell.)
Extend your right leg in front of you with your toes up, keeping your heel an inch or two off the floor.
Keeping your chest lifted, your back flat, and your core engaged, push your hips back and lower your butt onto the bench.
Return to the starting position without letting your right foot touch the floor.
Perform equal reps on both legs.