Written By: Chloe Wilson, BSc(Hons) Physiotherapy
Reviewed by: KPE Medical Review Board
Vastus medialis exercises are a great way to improve knee stability and function, reduce knee pain and reduce the risk of cartilage injuries.
Most people who suffer from long term knee pain have a weak vastus medialis muscle.
This alters the way the knee moves, how the forces are directed through the knee and places excess strain on the inner knee.
The great news is that vastus medialis strengthening exercises can easily be done at home or in the gym without the need for specialist equipment.
The vastus medialis muscle is the inner most of the four quadriceps muscles found on the front of the thigh.
The main bulk of vastus medialis is found just above the knee cap on the inner (medial) side of the knee.
If you clench your thigh muscles, vastus medialis forms a bulge on the inner thigh, often referred to as the tear drop muscle.
This part of the muscle is known as vastus medialis oblique, aka VMO or vastus medialis obliquus, as the muscle fibres here pass obliquely into the kneecap.
The vastus medialis muscle as a whole works with the other quadriceps muscles to straighten the knee and thus extend the leg.
Vastus medialis is particularly important in the final stages of knee extension where it helps with the locking mechanism of the knee joint.
The vastus medialis oblique (VMO) portion on the muscle has an extra function of helping to control how the kneecap moves and provides stability.
The shape of the knee means that naturally the kneecap would glide slightly over to the outer side of the knee when bending the leg. This would place excessive friction through the cartilage lining the back of the kneecap as well as increasing the risk of patella dislocation.
However, the positioning and direction of the VMO muscle fibres help to counteract this by drawing the kneecap inwards, or medially. This ensures that as the knee bends and straightens, the kneecap glides smoothly up and down the groove on the thigh bone so there is no friction on the back of the kneecap.
The main problems that develop in the vastus medialis oblique muscle are:
People with a weak vastus medialis oblique muscle are more prone to:
Most people suffering from anterior knee pain will benefit from doing vastus medialis exercises.
Vastus medialis and vastus medialis oblique are part of the same muscle so you don’t need to do different exercises for each part. But, you do want to make sure that VMO is activating properly.
Clenching a squashy ball between your knees as you do vastus medialis exercises really helps to make sure the VMO is switching on. A foam ball is best but if you don’t have one, use a soccer ball, just make sure has a bit of give in it by letting some of the air out.
We’ll start by looking at how to activate vastus medialis oblique and then look at a whole range of vastus medialis exercises.
Test both sides together, particularly if you have knee pain or swelling, as you may well notice a difference between sides.
Hold for 30 seconds and repeat 3 times. Don’t bounce on and off the stretch, it’s much more effective to hold the stretch. For more top tips on stretching, visit the knee stretches section
Once you can do 30 reps of each of these vastus medialis exercises with good control and are feeling confident that you are activating your VMO, you can progress onto more advanced exercises such as lunges, step ups and step downs without needing the ball.
Vastus medialis exercises are a great way to improve knee strength, stability and endurance and can really help to reduce knee pain.
To be most effective, they should also be combined with strengthening and stretching exercises for the other knee muscles:
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Page Last Updated: 09/02/23
Next Review Due: 09/02/25
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1. Journal of Orthopedic Research: Improving vastus medialis obliquus function reduces pressure applied to lateral patellofemoral cartilage. Elias JJ, Kilambi S, Goerke DR, Cosgarea AJ. 2009;27(5):578–583. doi:10.1002/jor.20791
2. Healthline: Vastus Medialis Origin, Function & Anatomy
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