Vastus Lateralis Muscle Anatomy, Function, Exercise

 

Vastus Lateralis Muscle

The Vastus Lateralis is the largest and most powerful part of the quadriceps muscle in the thigh and it is localized on the lateral side of the thigh. Together with other muscles of the quadriceps group, it serves to extend the knee joint, by moving the lower leg forward.

Vastus Lateralis muscle arises from a series of flat, broad tendons attached to the femur, and attaches to the outer border of the patella. It ultimately joins with the other muscles that make up the quadriceps in the quadriceps tendon, which continues to travel over the knee to connect to the tibia.

The vastus lateralis muscle is the recommended site for intramuscular injection in infants less than 7 months old and those unable to walk, with a loss of muscular tone.

Origin

The muscles that make up the vastus lateralis originate from the greater trochanter's base, the upper intertrochanteric line, the lateral linea aspera, the lateral supracondylar ridge, and the lateral intermuscular septum.

Insertion

An attachment of the lateral quadriceps tendon to the tibial tubercle.

Nerve Supply

The posterior division of the femoral nerve (L3,4) provides as the Vastus Lateralis' nerve supply.

Location

The vastus lateralis is situated on the lateral (outer) side of the thigh. It is the largest and most prominent of the four quadriceps muscles.

Blood Supply

The blood supply of the Vastus Lateralis muscle is the Lateral circumflex femoral artery.

Function of Vastus Lateralis:

Extension of the knee joint.

The vastus lateralis' main function is to straighten the leg by helping extend the knee joint. This movement is essential for many lower body movements, such as getting out of a chair, climbing stairs, and engaging in actions like cycling and kicking.

Importance in Sports and Exercise:

Sports and training involving lower body strength and power require the vastus lateralis to be strong and powerful. Athletes heavily rely on their quadriceps muscles, including the vastus lateralis, to generate force, drive oneself forward, or lift large objects, especially in sports like sprinting, weightlifting, and powerlifting.

Training and Rehabilitation:

After knee injuries or operations, a common objective of physical therapy and rehabilitation is to strengthen the vastus lateralis and the quadriceps as a whole. For this muscle group, exercises including leg extensions, squats, and lunges are frequently recommended.

Vastus Lateralis Antagonist Muscle

The hamstring muscle group is the opposing muscle to the vastus lateralis and the complete quadriceps muscle group. The hamstrings are positioned on the posterior (rear) side of the thigh and consist of three muscles: the biceps femoris, semitendinosus, and semimembranosus.

Synergist Muscle

Rectus femoris
Vastus intermedius
Vastus medialis

Clinical significance

Patellofemoral pain syndrome

Some evidence has shown that in patients with patellofemoral pain syndrome vastus lateralis muscle contracts prematurely when compared with vastus medialis muscle which has been hypothesized to be a reason for knee pain. This leads to pain and difficulty during walking and running.

Vastus lateralis muscle strain

A sudden force to your thigh may cause the vastus lateralis muscle to be strained. This can cause pain, swelling, and bruising of your thigh, and may limit your ability to walk normally.

Patellar tendinitis

Irritation of the quadricep tendon that courses over your kneecap may cause patellar tendinitis.

Weakness due to femoral nerve compression

Your femoral nerve can be pinched or irritated due to lumbar stenosis, arthritis, or a herniated disc. When this occurs you may feel pain, numbness, tingling, or weakness in your thigh.

Exercise for the vastus lateralis muscle

The vastus lateralis and other quadriceps muscles must be exercised regularly to strengthen the lower body, enhance sports performance, and maintain general knee health.

The following are some efficient workouts that target the vastus lateralis:

Static quadriceps exercise (SQE)

Sit on a flat surface or lie down on your back, ensuring your knee is fully extended (straight).
If you're lying down, place a small rolled-up towel or a soft object under your knee for comfort and to provide a slight bend, usually around 10-15 degrees.
The quadriceps muscles (located on the front of the thigh) of the affected leg should be tightened and contracted.
Try to imagine pressing the back of your knee against the ground or other surface you're on.
For five to ten seconds, maintain this contraction. During this time, make sure to keep your contractions constant and powerful.

Straight leg raises (SLR)

Your typical lower leg should be bent at the knee at a 90-degree angle, with the foot firmly planted on the ground. By tensing your quadriceps muscles (the group of muscles on the front of your thigh), you may stabilize the muscles on your straight leg. Lift the leg straight approximately six inches off the ground while taking a slow, deep breath.

Leg Extensions

This exercise directly targets the quadriceps, with a focus on the vastus lateralis. Use a leg extension machine:

Take Sitting position on chair or Bed with your knees bent at 90 degrees.
Extend your legs, lifting the weight with your quads.
Slowly return to the starting position.

Squatting

Stand up with your feet shoulder-width apart, resting your arms straight down at your sides.
Bracing your core and keeping a chest up, begin to push your hips back, bending your knees as if you’re going to sit down. Ensure that your knees don’t cave in. Pause while your thighs are level with the floor.
Press your heels into the ground to return to the initial position.
Repeat until the set is complete.

Step-Ups:

Step-ups can be done using a sturdy bench or platform.

Place one foot on the bench or platform.
Lift your body up by applying pressure via the heel of the lifted foot.
Step back down and repeat.
Alternate legs.

Cycling:

Riding a bicycle is an excellent cardiovascular exercise that engages the vastus lateralis, especially during the downstroke of each pedal.

To avoid injury and enhance muscle engagement, it's crucial to maintain good form when executing these exercises. Start with a suitable weight or amount of resistance, then progressively up the intensity as you get stronger and more at ease. To reduce the chance of muscle strain or injury, warm up before exercise and cool down afterward.