Vastus Medialis Exercises to Stabilize the Knee Joint

Medically reviewed by Peggy Pletcher, MS, RD, LD, CDE on January 20, 2016Written by Kat Miller on January 20, 2016
Vastus Medialis Exercises

The vastus medialis oblique (VMO) is one of the four quadriceps muscles, located on the front of your thigh, just above your kneecap.

Your VMO is technically the only muscle attached to your kneecap that is responsible for stabilizing your patella and keeping it in line when you bend your knee. If you suffer from knee pain or have a knee injury, it’s usually due to the VMO fibers fatiguing or the other muscles that stabilize the patella not reacting properly. Any weakness in the muscles supporting your knees can cause your patella to shift off track and cause serious damage.

Knee injuries are among the most common injuries, whether you’re a pro athlete or a sedentary 65-year-old. People assume since your knee is a joint, that you can’t strengthen it. But while you can’t technically strengthen your joint, there are ways to strengthen your muscles around your knees to help stabilize the knee and avoid injury.

It’s also extremely important to strengthen the muscles that support your knee before you undergo a knee replacement, if necessary. This will help put you on the path to a speedy recovery. Let’s a take a look at some exercises to strengthen around your knees that you can perform weekly in the comfort of your own home or at the gym.

1. VMO Floor Extension

This exercise isolates your VMO since sitting against a wall does not allow your hips, glutes, and hamstrings to assist.

Equipment used: mat, wall, and ankle weights (optional)

Muscles worked: vastus medialis oblique, quadriceps

  1. Sit down on the floor with your back, shoulders, and glutes up against the wall. Sit up tall and bend your left knee in toward your chest with your left foot flat on the floor. Extended your right leg in front of you with your foot slightly pointing out to your right. Hold under your left knee with both hands interlocked and keep your right quad flexed for the duration of this exercise.

  2. Exhale. Without leaning away from the wall, lift your right leg up in the air as high as you can. Hold this position for 1 count.

  3. Inhale and slowly lower your right leg back down to your starting position. Try not to slam your right heel back down.

  4. Do 12 repetitions for 3 to 4 sets, and then switch legs. If you find this exercise fairly easy, add an ankle weight lying across the thigh (not on the ankle) of the extended leg, and perform the same exercise for the same amount of repetitions.

Expert tip: If you aren’t able to lift your leg up at all, don’t get discouraged. It’s quite common, and just means you need to strengthen your VMO. You should, however, feel a contraction above your knee to show your VMO is trying its best. Put your right hand over the inside of your right quadricep just above the knee. As you flex the quadriceps, you should feel your VMO contracting. As you get stronger, you’ll be able to lift your leg up off the floor.

2. Lateral Heel Drop

This move helps strengthen your VMO, glutes, and lower back so you can perform lunges and squats properly without any pain in your knees. It is used to strengthen the muscles stabilizing the knee joint and during knee rehab. Both knees will be strengthened at the same time in this exercise. One knee will always be pushing off the step, while the other knee will be contracted and controlling the descent during this exercise.

Equipment used: stepper and ankle weights (optional)

Muscles worked: vastus medialis oblique, quadriceps, hamstrings, and calves

  1. Stand tall with your left leg straight but not locked and your right foot resting on a small step. Your right knee should be slightly bent and your left foot should be flat on the floor. Your right knee should not be going over your toes. Squeeze your core for balance.

  2. Exhale and push up off your right leg until both legs are fully straightened. Try to keep your hips level as you step up.

  3. Inhale, contract your left quadriceps, and slowly lower your left foot back down to your starting position.

  4. Repeat 15 times for 3 to 4 sets, and then repeat with your left leg on the stepper and your right leg on the floor, controlling the negative part of this movement.

Expert tip: Use a small step. You don’t want to feel a sharp pain in either knee because of the lateral pressure you’re putting on it.

Take It to the Next Level: Step Downs

Stick with the same low step to ensure stabilization and comfort in the knee joint. You can always progress to a higher step when you feel more comfortable and your VMO gets stronger. Like the previous exercise, this move will strengthen both knees at the same time.

Equipment used: stepper, and ankle weights (optional)

Muscles worked: VMO, quadriceps, hamstrings, and calves

  1. Stand with both feet on top of the step, facing forward.

  2. Inhale. Flex your left quadriceps and step your left foot off the stepper, bending your right knee until your left foot is flat on the floor. Again try to keep your hips level at all times.

  3. Exhale, engage your core, push off your left foot, and come back onto the stepper back to your starting position.

  4. Repeat 15 times for 3 to 4 sets, then switch legs.

3. Leg Extension

You will need a leg extension machine to do this move. However, you will modify the range of motion, because the way this machine is commonly used puts too much pressure on the knee joint. This exercise takes the first exercise “VMO floor extension” to a whole new level with added weight.

Equipment used: leg extension machine

Muscles worked: vastus medialis oblique and quadriceps

  1. Adjust the seat so the lower leg pad sits on your ankle. Make sure your knees form a 90-degree angle. Pick an appropriate weight (you will be performing this exercise with both legs), squeeze your core tight, and hold onto the handles if you need to.

  2. Exhale and in one motion swing the leg pad all the way up until your legs are fully extended out in front of you.

  3. Inhale, contract your quadriceps, and lower the leg pad down only 30 degrees. Lowering the pad down by 30 degrees really forces your VMOs to contract. You should at least see both of your VMOs sticking out contracting or at least feel it with your hand.

  4. Perform 15 repetitions for 3 to 4 sets. Adjust the weight accordingly as you get stronger, but remember to keep that 30-degree angle only when performing knee rehab.

Variations: You can perform a single leg extension instead of using both legs. You can also switch up your feet placement: Instead of forming a diamond shape with your feet facing in, perform this exercise with both feet facing out or pointed straight. All these variations will help improve your knee stability and strengthen your VMO from every angle.

4. Single Leg Raises

This exercise can be performed anywhere with or without equipment.

Equipment used: mat or flat surface, towel, and ankle weights (optional)

Muscles worked: vastus medialis oblique, quadriceps, hamstrings, calves, and glutes

  1. Lie on your back with your left knee bent and your left foot flat on the mat. Fully extend your right leg out in front of you, adding an ankle weight with an appropriate amount of weight to your thigh area if desired (lay the weight across your thigh; do not strap it onto your ankle). If this is your first time performing this exercise, don’t use a weight.

  2. Squeeze your core, contract your right quadricep and VMO, and lift your right leg about 2 inches off the mat and keep it elevated for the duration of this exercise. Make sure you’re not arching your back. You don’t want any space between your back and the mat.

  3. Inhale. With your right quadricep contracted, raise your right leg up until your right thigh is even with your left thigh. Hold this position for 1 count.

  4. Exhale and in a slow controlled manner, lower your right leg down to your starting position, keeping it about 2 inches away from the mat.

  5. Repeat 15 times for 3 to 4 sets, then switch legs.

Expert tip: It’s important to raise your right leg only as high as your left thigh. If you raise it any higher, you’re not strengthening your knee, you’re challenging your hip flexibility. That’s not what this exercise is for.

5. Terminal Knee Extensions (TKEs)

Sounds a little scary but definitely a favorite as a warmup before training.

Equipment used: 2 resistance bands

Muscles worked: VMO and quadriceps

  1. Loop a resistance band around a sturdy surface and slide the other end slightly up above your right knee; face toward the surface that is holding the band in place. Take a few steps back so the band is taut. Straighten your left leg and keep your right knee slightly bent with your right heel off the floor.

  2. Exhale and push your right heel down to the floor, and really exaggerate contracting your right quadricep. Again, you want to see or at least feel the VMO tightening and contracting. Hold this position with resistance for 1 count.

  3. Inhale, slowly release the tension in the resistance band, and lift up your right heel back to your starting position. If you didn’t feel any resistance in your VMO, grab a thicker band or take another step back away from the anchor, making the band more taut.

  4. Perform 15 repetitions for 3 to 4 sets, and then repeat on your left leg.

The Takeaway

Strengthening the muscles and ligaments around your knee joints is an important way to stabilize them. It doesn’t matter how old or athletic you are; everyone tends to get some kind of knee pain at some point in their lives. Whether preparing to squat 275 pounds or walking up the stairs, you should perform at least one knee stabilization exercise weekly to prevent knee pain and injuries.

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