Vastus Lateralis & Intermedius Exercises

To obtain the strongest and most attractive legs possible, special attention needs to be given to the vastus lateralis and intermedius. By targeting these two quadriceps heads while training, you develop the outer portion of your thighs and stop your knees from turning inward while squatting. The difference between fully developing your quadriceps -- and looking good in your shorts -- or watching your knees buckle during exercise is training up the vastus medialis and intermedius.

A woman is strength training her legs. (Image: Ibrakovic/iStock/Getty Images)

Do My Thighs Look Big?

One of four quadriceps heads, the vastus lateralis is the head on the outer portion of your thighs. This muscle is visible when your leg is viewed from the front and can either make you or break you in a new pair of shorts. During squats or leg presses, this muscle is also responsible for keeping your knees from turning inward and buckling together. Vastus intermedius development makes your rectus femoris -- another quadriceps head -- more pronounced and improves the appearance of your legs from the side.

Squatting for Success

Directly training the vastus lateralis requires a conscious effort while lifting. Set aside some time on leg day to work on your squat technique. Your feet should be shoulder width apart, and when you lower your body, your knees should not buckle in toward one another. The reason for this buckle is that the vastus medialis -- inner quadriceps head -- is stronger than the lateralis, and during activation the lateralis cannot maintain proper form. Consciously keeping your knees apart requires the lateralis to activate and strengthen.

I Prefer Machines Over Squats

The machine leg press offers the advantage of bodily stability, so you can focus on and strengthen the vastus lateralis. When setting up your press, ensure that your lower back is well supported between the seat and back pad. Place your feet on the center of the foot plate at shoulder width, then slide them down 1 to 2 inches -- for quad focus. Tie a resistance band around your knees and during your presses, ensure that your knees hold the band in place and that it stays tight.

A Strong Supporter

For getting the most out of your vastus intermedius, you want to train one leg at a time. Using only one leg requires the intermedius to support and stabilize the entire leg, activating as much of the head as possible. Depending on your level of training, beginners start with a body-weighted walking lunge while more advanced trainers can move on to single leg splits or the barbell lunge.