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What is the Vastus Lateralis?

Alex Paul
Alex Paul

The vastus lateralis is the largest muscle in the quadriceps group. It is located on the outer portion of the thigh and is important in any movement that requires knee extension. The muscle also helps stabilize the patellar. Although the muscle is the strongest and biggest in the quadriceps femoris muscle group, it works in conjunction with the other three in order to provide stable leg extension at the knee joint.

The quadriceps are made up of four main muscles that assist in a range of actions of the leg. These are known as the vastus lateralis, medialis, intermedius and rectus femoris. The vastus lateralis is the largest muscle in this group and hence has a major role to play in stabilization of the knee.

Side lunges strengthen and tone the thighs -- including the vastus lateralis -- and other leg muscles.
Side lunges strengthen and tone the thighs -- including the vastus lateralis -- and other leg muscles.

The origin of the vastus lateralis is on the femur near the hip. It then runs down the lateral side of the thigh and attaches to the knee via the quadriceps tendon. This is also where the other two vastus muscles insert although the rectus femoris inserts at the patella tendon. The innervation of the muscle is via the femoral nerve.

Any movement that requires extension of the knee will invoke the vastus lateralis muscle. For example, walking up or down stairs will require the muscle in order to avoid excessive mobility in the knee joint. Exercises such as cycling also require the vastus lateralis to be strong.

The vastus lateralis helps extend and stabilize the knee.
The vastus lateralis helps extend and stabilize the knee.

Due to the importance of the vastus lateralis in sporting activities, a number of exercises have been developed to improve the muscle’s strength. For example, squats are a good exercise for working all the quadriceps muscles. Leg press machines can also achieve similar results. Quadriceps strains are relatively common and are categorized as grade one, two or three depending on the severity.

The vastus lateralis is used when extending the leg.
The vastus lateralis is used when extending the leg.

Problems can arise when the vastus lateralis is too strong compared to the vastus medialis, which is located on the inner side of the thigh. These two muscles are thought to work together in order to allow the patellar to track in the patella-femoral groove. Many cyclists, runners and other athletes have weak vastus medialis muscles, which causes lateral tracking of the patellar and can result in a number of knee problems. There is still some debate, however, about the significance of the strength of these two quadriceps muscles or whether knee problems are more likely to arise from issues in the hip and ankle.

Discussion Comments

kylee07drg

@orangey03 – I know of one good vastus lateralis stretch. I like to do this one after working out on my exercise bike. It helps my muscles transition from a state of stress to relaxation.

I lie on my side and pull my top foot up behind me toward my back. I hold this position for about ten seconds.

Then, I take my other leg and bend it at the knee. I bring that foot over my top knee and press down on it. I do this for another ten seconds, and then I flip over and do the other side.

orangey03

Leg squats are some of the most intense exercises you can do. I have gotten sore thigh muscles from doing less than five of these before.

Now, I have increased my resistance. I can do ten leg squats before my vastus lateralis starts to feel fatigued. I can feel the muscles bulging a little in my leg, and I know that the squats are working.

Does anyone know of any good vastus lateralis stretches? I've got the toning part down, but I want to be able to stretch them after a workout to avoid injury.

StarJo

I suddenly became very aware of my vastus lateralis after enrolling in college. It seemed that most of my classes were up several flights of stairs, and my legs nearly gave out during my first day of climbing.

I stayed sore for the first couple of weeks. After that, my muscles adapted, though I was still winded after steep climbs.

About two months into classes, I went on a weekend hiking trip with some friends. I then noticed that in addition to having greater lung capacity than them, my vastus lateralis powered me up hills much faster than theirs did. They were sore for days afterward, but I was fine.

When I graduate from college, I guess I will have to live in a house or apartment with stairs so I can keep in shape. It would be a shame to let this muscle tone go to waste!

cloudel

When I was a teenager, I did lots of vastus lateralis exercise without even realizing it. I rode my bike up hills and across miles of paths, and my leg muscles were growing very strong.

I stopped riding for years after one of my dogs got killed by a car while following me. I didn't get on a bicycle again for about seven years, and when I did, I could tell that my vastus lateralis no longer had much power in it. I could not even endure a half-mile ride.

Riding a bike when you aren't used to it can make your legs very sore quickly. After my first attempt in years, I was stiff and sore for three days.

That only made me more determined to get back in shape, though. I now ride a little bit three days a week, and I am slowly increasing the length of my rides each time. I want to get back my awesome vastus lateralis that I had as a teenager.

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    • Side lunges strengthen and tone the thighs -- including the vastus lateralis -- and other leg muscles.
      By: z3zo
      Side lunges strengthen and tone the thighs -- including the vastus lateralis -- and other leg muscles.
    • The vastus lateralis helps extend and stabilize the knee.
      By: Dirima
      The vastus lateralis helps extend and stabilize the knee.
    • The vastus lateralis is used when extending the leg.
      By: CandyBox Images
      The vastus lateralis is used when extending the leg.
    • Leg press machines can help improve the strength of the vastus lateralis.
      By: Valeriy Lebedev
      Leg press machines can help improve the strength of the vastus lateralis.
    • Weak vastus medialis muscles can lead to a number of knee problems.
      By: evgenyatamanenko
      Weak vastus medialis muscles can lead to a number of knee problems.
    • Many runners have weak vastus lateralis muscles.
      By: Warren Goldswain
      Many runners have weak vastus lateralis muscles.