Written by Garett Reid | NSCA, CSCS, CISSN, M.S.E.S.S
Fact checked by Kiel DiGiovanni, Co-founder
FACT CHECKED
Leg day is back, baby! Training legs has become a new "it" muscle muscle lately, making it just as, if not more important, as a set of biceps or chest. And what leg muscle do you see when you turn and look at someone? The quadriceps, of course. This single muscle has four different muscles, and one of these, perhaps the least well-known, is the unseen vastus intermedius. It's the only quadricep muscle that sits deep, meaning the others lie on top. But this doesn't mean it's not important. If you want big quads, you gotta train them, so here are the best vastus intermedius exercises to build your thighs.
The Quadriceps Muscle
The quadriceps muscle is the leg's primary extensor. It sits on the front of the upper thigh, accounting for half of its size. Its origins are located at the hips, and it runs down the front of the leg, finally inserting across the knee.
However, what we think of as a single muscle is actually composed of four different muscle heads; one of those heads is known as the vastus intermedius, and that will be where our focus is in this article.
However, before we look at the vastus intermedius more in-depth, let's quickly review the other three muscle heads.
Rectus Femoris
The rectus femoris sits on the middle of the thigh and is unique among the four quadricep muscles. Unlike the other three vastus muscles, the rectus femoris crosses the knee and the hip. This means it's involved in both knee extension and hip extension.
Related: Best Rectus Femoris Exercises
Vastus Lateralis
The vastus lateralis is located on the "lateral" side of the thigh, meaning it is on the outside of the thigh. It is the strongest muscle head of the quadriceps and helps create a "swollen" thigh.
Related: Best Vastus Lateralis Exercises
Vastus Medialis
The vastus medialis runs down the inner thigh and reaches down the farthest. It also plays a major role in tracking the patella (knee cap) and is often involved in knee injuries. Many people know the vastus medialis as the "teardrop" muscle due to the shape it makes as it sits across the knee.
Related: Best Vastus Medialis Exercises
Vastus Intermedius
The vastus intermedius isn't the most popular muscle; many people don't even know it exists. One reason is that you can't see it, no matter how shredded you get.
The vastus intermedius origin is found on the outside of the femur in its upper region. It then runs down the middle of the thigh where it merges into the quadriceps femoris tendon and inserts across the knee.
However, even though it's quite large, you can't see it as it sits underneath the rectus femoris. It runs continuously with the vastus medialis; researchers initially believed these two muscles to be inseparable.
When it comes to the function of the vastus intermedius, it works in unison with the other quadriceps muscles to help extend the quadriceps. Other than that, it doesn't really have a special function, nor does it seem to have any specific exercise to target it. However, there are two interesting points to make.
Two Unique Aspects Of The Vastus Intermedius
The first goes back to what we said earlier about it being inseparable from the vastus lateralis. It would then seem that these two would have similar activation with similar movements. However, we weren't able to find any solid research to collaborate on this.
Another interesting observation is the relationship between the vastus intermedius and the quadricep muscle as a whole. Some research has suggested that alterations in the vastus intermedius from resistance training can be a reliable indicator of the alteration and muscle growth of the quadriceps as a whole.¹
If the vastus intermedius is a good indicator of total quadriceps growth, it makes sense to assume that total quadriceps growth indicates the growth of the vastus intermedius.
All we're trying to say is that when you're choosing exercises to train the vastus intermedius, simply use exercises that will cause the most growth in your quadriceps.
6 Best Vastus Intermedius Exercises
Now, let's get into training the vastus intermedius. Trying to find specific studies that look at the vastus intermedius is surprisingly difficult, but it makes sense. Remember that the vastus intermedius sits under the other muscles. This makes it very difficult to get EMG readings that use surface electrodes or needles.
That said, we know that the vastus intermedius is strongly associated with the growth of the quadriceps as a whole. Further, it runs in line with the vastus medialis, which could possibly give us some hints if we wanted to try and target it. Mind you, we say "target," as it's impossible to isolate any of the quadricep muscles from one another.
1. Barbell Back Squat
The back squat will always be the go-to exercise to train the quadriceps and, by default, train the vastus intermedius. When you train them, they're going to train every single muscle in the lower body while building mass amounts of strength as well.
When performing them, many people argue about high-bar back squats and low-bar back squats. Research isn't the clearest on which will elicit greater gains in the quads if any of them do. However, if there were one, it would be the high bar squat.
How To Perform The Barbell Back Squat
- Set up a barbell on a squat rack around chest height. Get under the bar so it's resting firmly across your upper traps, not on your neck, and use an overhand grip around shoulder-width apart. Keep in mind that grip width will vary from person to person.
- Unrack the bar and take a step back.
- Engage your core like you're bracing for impact. Initiate the squat by pushing your hips back and letting your torso drop. Keep your back flat for the entire movement.
- Let your knees come forward as long as they're tracking your toes. Continue until your thighs are parallel or lower.
- Once you hit depth, power through your heels and thrust those hips forward to rise back up. Keep that core tight and maintain your upright stance, ensuring your shoulders rise with your hips. Continue until you're standing with your hips fully extended.
2. Safety Bar Squat
One alternative to the barbell squat is to use a safety squat bar. A safety squat bar sits higher on your back and has handles to help with shoulder mobility. Due to the higher position, your torso will be more erect, resulting in less hip flexion and greater knee flexion.² Greater knee flexion and extension mean more quadriceps activation and a bigger, stronger vastus intermedius.
3. Front Squat
The front squat is the squat more people need to be doing, especially if they want to grow their quadriceps and vastus intermedius. In fact, many strength coaches involved in athletic and performance training believe the front squat is superior for overall athletic development and quad strength.
As the name implies, the front squat is performed by performing a squat with a barbell placed in front of the body. The difference with the back squat vs front squat is the weight is now in the front of the body, the torso must stay upright, which results in less hip flexion, making knee extension the primary mover. As your vastus intermedius is one of the primary knee extensors, you'll surely hit it significantly.
How To Perform A Front Squat
- Set that barbell on the squat rack at chest level. Grab the bar with a grip slightly wider than shoulder-width apart.
- Get under the bar and let the bar rest on your front delts. You can then either cross your arms to hold the bar or use a clean grip (fingers under the bar, elbows high). Make sure your elbows are up throughout the movement.
- Unrack the bar and step out. Plant your feet shoulder-width apart, or a touch wider, with toes slightly turned out.
- Brace your core and start your descent. Keep your chest up and your back straight as you push your hips back and sit.
- Drop down until your thighs are at least parallel to the ground or deeper if you've got the mobility.
- Once you hit the bottom, explode up by pushing through your heels and driving your shoulders up. The key is to drive your elbows up as you ascend; this will keep your torso vertical.
- Continue until your hips are fully extended.
4. Hack (Machine Based)
The machine Hack squat is one of those movements you probably know, or at least have seen, but just don't know it's called a Hack squat. This awesome quad exercise was "invented" by an old-time wrestler and Strongman, George Hackenschmidt. Most people will assume that's why it got the name "Hack" squat. While that makes sense, it received the name due to the similarities in the close foot placement during the movement. This resembled the way Prussian soldiers clicked or hacked their heels.
When he initially performed this movement, it essentially looked like a deadlift performed behind his legs. This forced the torso to stay upright and placed the majority of the action on knee flexion and extension. Mr. George Hack explained that he wanted to limit the stress he placed on his back while still lifting a lot of weight and building strength.
As time evolved, someone built a machine to replicate the movement. The hack squat machine usually sits at a 45-degree angle with a sled that the person lays on. With the back supported, the knees are the primary movers, and as knee extension is the quadriceps's primary function, it's a great vastus intermedius exercise.
How To Perform The Hack Squat
- Make any necessary adjustments on the machine for a proper setup. Plant your feet firmly on the foot platform, shoulder-width apart or slightly wider, with toes pointed out just a touch.
- Settle under those shoulder pads like you're gearing up for battle. Your back should be firmly pressed against the backrest. Grab the safety handles, stand up, and unrack.
- Let the sled come down while keeping your knees aligned with your feet. Drop down until your thighs are at least parallel with the platform, or lower if you've got the mobility. At the bottom, your shins should be vertical, and your thighs should be parallel to the ground. You can make any adjustments before continuing with your other reps.
- Drive your feet into the platform and drive the sled up.
5. Bulgarian Split Squat
The Bulgarian split squat, also known as the rear foot elevated split squat (very specific), is notorious for killing quads—well, at least if you perform it correctly for quad development.
As its extended name says, the Bulgarian split squat is performed by performing a split squat but raising the rear leg up behind you. This mitigates the involvement of the rear leg, placing the load on the front leg. It's a unilateral exercise that can be used as a transitory step to a single-leg squat.
When you perform it, realize you can alter the biomechanics slightly, and therefore the muscle activation, by altering your foot placement. To make it a better vastus intermedius exercise, don't step as far out with the front foot. When your torso lowers, the closer foot placement will cause more flexion in the knee, resulting in greater involvement of the quads.
How To Perform The Bulgarian Split Squat
- Set up a bench to support your back foot.
- Stand in front of the bench and place the top of your back foot on the bench. The exact setup will vary from person to person, so you'll probably need some time to find the right spot.
- Keeping your torso up high, let your body drop straight down. Many people tend to let their body come forward; don't do this.
- Let your body drop all the way down. At the bottom, your back knee should lightly touch the ground.
- Because you want to focus on the vastus intermedius, you'll want your front foot to be placed so your knee will slightly come forward. The exact distance will vary for the person and will depend on what they're comfortable with.
- Drive your front foot into the ground to propel your body back up.
6. Stationary Lunges
The stationary lunge is another great vastus intermedius exercise similar to the Bulgarian split squat. There are quite a few different lunge variations, such as the reverse lunge or walking lunges. However, you want to perform stationary lunges to focus on the quads.
A stationary lunge involves stepping one foot out, letting your torso descend, and then pushing your body back up. This version emphasizes powerful knee extension to push the body back, meaning your vastus intermedius will be put to work! Compare this to a walking lunge, when you step one foot out and then pull your body forward; this concentrates on the glutes and hamstrings.
When performing these, you can opt to use body weight for maximal volume or use a load such as a barbell or holding kettlebells.
How To Perform The Stationary Lunge
- Decide if you're going to load the movement.
- Stand with your feet hip-width apart. Take a step forward about 1.5x your normal stride. You'll probably need to adjust some if this is your first time. When you hit the bottom of the movement, your back thigh should be vertical, and your front shin should be.
- Once stepped out, let your torso drop while keeping your torso erect and shoulders back. Let your body drop straight down. (Many people tend to come forward as they descend).
- Come down until your rear knee lightly touches the ground; we'll say "kiss the ground".
- Keeping your torso tall, push your front foot into the ground to propel your body back. Repeat the desired reps.
Other Vastus Intermedius Exercises
Here's a quick list of some other vastus intermedius exercises you could use;
- Leg press (Narrow stance, low stance)
- Leg extensions
- Sumo squats
- Split squats
Training Variables To Maximize Growth Of The Vastus Intermedius
We wanted to quickly review some training variables to maximize vastus intermedius growth. This is just a refresher:
- Use a range of loads and reps
- Use some ultra-high reps once in a while
- Train the vastus intermedius twice a week
- Use a variety of vastus intermedius exercises.
Final Say On Training The Vastus Intermedius
The vastus intermedius is a muscle that's never seen but plays a massive role in human movement. Unfortunately, finding EMG readings on it is very hard due to its location. However, as we mentioned, the growth of the vastus intermedius seems to grow along with your overall quadriceps growth. This just means you don't need to worry too much about isolating it with any specific exercise; you just need to blast your quads with the exercises in this article, and your vastus intermedius will grow!
Check out our full collection of quad exercises!
References
- Spiliopoulou, Polyxeni, et al. “Vastus Lateralis and Vastus Intermedius as Predictors of Quadriceps Femoris Muscle Hypertrophy after Strength Training.” Applied Sciences, vol. 12, no. 18, 12 Sept. 2022, p. 9133, https://doi.org/10.3390/app12189133. Accessed 20 Oct. 2022.
- Johansson, David G.; Marchetti, Paulo H.; Stecyk, Shane D.; Flanagan, Sean P.. A Biomechanical Comparison Between the Safety-Squat Bar and Traditional Barbell Back Squat. Journal of Strength and Conditioning Research 38(5):p 825-834, May 2024. | DOI: 10.1519/JSC.0000000000004719
Garett Reid
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