Best Quad Isolation Exercises for Strength and Mass

Many so-called fitness experts believe that squats are the only exercise you need to do to blow up your quads. Social media is full of memes extolling the benefits of squats – especially the ass-to-grass variation.

However, while squats ARE an excellent leg exercise, they may not be the best way to grow your quads. That’s because squats are a compound exercise that also work your glutes and hamstrings. As such, much of the weight during squats is spread between different parts of your body.

So yes, squats DO work your quads, but other muscles are very active, too.

There are other drawbacks to squats, too. For example, some people find them uncomfortable, so they finish their sets before their quads are fatigued. Squatting to failure can also be an issue and could result in severe injury. Some people simply do not respond well to squats. Tall lifters are often squat non-responders.

In the same way you do curls for your biceps and pushdowns for your triceps, it makes sense to include isolation exercises in your leg workouts to hammer your quads. Of course, that doesn’t mean you need to give up squats, but you probably need more than the “king of exercises” to build the best possible lower body.

In this article, we reveal the nine best quad isolation exercises.

What Are the Quad Muscles?  

While you don’t need a degree in anatomy to build massive quadriceps, aka the quads for short, it may be helpful to know a little more about this powerful muscle group so you can choose the best exercises.

The term quadriceps refers to the fact that this body part comprises four individual muscles. The four quadriceps have separate origins or starting points and come together at a single insertion point called the quadriceps tendon.

The four quadriceps are:

Rectus femoris

The rectus femoris is the longest of the quadriceps muscles. It’s also biaxial, meaning it crosses two joints. As such, the rectus femoris has two primary functions: knee extension and hip flexion.

Vastus medialis

Where rectus femoris is the longest quadriceps muscle, vastus medialis is the shortest. This muscle is just above your knee and shaped like a teardrop. It’s responsible for straightening the knee and is most active in the last few degrees of extension.

Vastus intermedius

Located between vastus medialis and vastus lateralis, this long muscle really stands out at the front of your thighs. It’s a very powerful knee extensor and makes up much of the bulk of your anterior thighs.

Vastus lateralis

The vastus lateralis is the largest, strongest muscle in the quadriceps group. It’s located on the side of your thigh and gives your quads their width. Well-developed vastus lateralis gives your thighs a pleasing shape, which is often called the quad sweep.

Isolation vs. Compound Exercises – What’s the Difference?

An isolation exercise is one that involves movement at just one joint and targets a small number of muscles. In contrast, compound exercises involve two or more joints and several muscles.

While there are several great quad isolation exercises, there are also several effective compound exercises that emphasize the quads.

To provide you with plenty of choices, we’ve included true quad isolation exercises and a few compound movements that hit your quads particularly well. Think of these latter exercises as semi-isolation, as the quads are doing most of the work.  

Quad Exercises Using Leg Extensions  

Most gyms have a leg extension machine, and you can also do leg extensions with a dumbbell or resistance bands. Keep reading to find out how!

1. Machine leg extensions

The leg extension machine is arguably the daddy of quad isolation exercises. With all the movement coming from the knee, this is the truest way to isolate your quadriceps. Because it’s performed while sitting upright, the rectus femoris is in a relaxed position and not as active as it could be. However, the three vastus muscles are all working hard during this exercise.

How to do it:

1. Sit on your leg extension machine, so your knees align with the lever arm pivot point. Adjust the backrest for comfort and support.
2. Place your ankles behind the lower leg pad. Grip the handles by your sides.
3. Smoothly extend your legs until your knees are straight. Do not kick the weight up, as doing so creates momentum and takes tension off your quads.
4. Pause in the top position for 1-2 seconds.
5. Bend your knees and lower the weights but do not let them touch to keep the tension on your quadriceps.
6. Extend your legs and repeat.

2. Machine single-leg extensions

It’s often advantageous to train one leg at a time. This allows you to work both legs equally and ensure that one leg isn’t stronger than the other. Plus, if you DO have a size or strength imbalance, you can do an extra few reps or another set for the side that needs more attention. Single-leg training is also a great way to strengthen that all-important mind-muscle connection.

How to do it:

Perform as above but only lift and lower the weight with one leg.

3. Dumbbell leg extensions

The machine leg extension might be the best way to isolate your quads, but that’s no help if you train at home and don’t have the necessary equipment. Thankfully, you can also do leg extensions with a single dumbbell.

How to do it:

1. Sit on the end of an exercise bench with the backs of your knees against the edge. Hold a dumbbell between your feet.
2. Squeezing your feet and legs together, extend your legs until they’re straight.
3. Bend your legs and repeat.

4. Leg extensions – isometric holds

Isometrics is a form of training where you hold a weight stationary instead of lifting and lowering it. Isometrics allow you to train with heavier-than-normal weights and keep your muscles under constant tension.

Leg extension isometric holds really hammer your quads and could even help develop better quad separation and more defined legs. However, with no opportunity to relax your quads, lactic acid will build up pretty fast, and your legs will soon start to burn!

How to do it:

1. Sit on your leg extension machine, so your knees align with the lever arm pivot point. Adjust the backrest for comfort and support.
2. Place your ankles behind the lower leg pad. Grip the handles by your sides. Smoothly extend your legs until your knees are straight.
3. Hold your legs straight while tensing your quads as hard as you can.
4. Breathe through the pain and keep the weight up for as long as possible.

You can also do this exercise using one leg at a time, i.e., single-leg extension isometric holds.

5. Single-leg resistance band leg extension

Resistance bands are very versatile, and you can use them to replicate most freeweight and machine exercises. As well as being cheap and portable, most resistance band exercises are also very joint-friendly, as there is no initial inertia to overcome, and the resistance increases gradually. You can use a resistance band to isolate your quadriceps.

How to do it:

1. Sit on a chair or bench and tie a resistance band around one ankle. Anchor the other end on something immovable, such as a heavy dumbbell or your chair/bench leg.
2. Extend your leg until your knee is straight.
3. Lower your leg and repeat.
4. Perform the desired number of reps and then swap legs. Do the same number of reps on both sides.

6. Bodyweight leg extension

It’s true; you don’t need any equipment to isolate your quads! This move is ideal for home exercisers and, as well as building your quads, it’ll help mobilize your knees and ankles, too. Kneel on a folded towel or gym mat for comfort.

How to do it:

1. Kneel down, so your thighs are vertical. Extend your ankles and press the tops of your feet into the floor.
2. Keeping your hips extended, bend your knees and lean back as far as you can, lowering your butt toward your heels.
3. Use your quads to push you back into the starting position and repeat.

Quad-Dominant Squat Exercises

While these aren’t true isolation exercises, they do allow you to emphasize your quads more than your glutes and hamstrings. As such, they deserve a place in your quad-building workouts.

1. Front squat

If you want to work your quads with squats, the front squat is a better choice than the back squat. Front squats feature a more upright torso, more knee flexion, and less hip involvement, so your quads have to work considerably harder.

However, front squats require more mobility and flexibility, so they may not be practical for everyone. If you find front squats uncomfortable, check out exercise #10, which is similar but more accessible for most people.

How to do it:

1. Put a barbell in your squat rack at about shoulder height so you don’t have to stand on tiptoes to unrack it.
2. Walk forward and put your anterior (front) deltoids against the bar. Grip the bar with your hands just wider than shoulder-width apart. Depending on your flexibility, this may mean you can only get your fingertips to the bar and cannot fully wrap your hands around it. That’s ok; the bar should sit in the creases of your shoulders and remain in place even if you aren’t gripping it with your hands.
3. Push your elbows forward and under the bar so your upper arms are parallel to the floor. The bar should rest against your neck, but it should not press heavily on your throat.
4. Brace your core and pull your shoulders down and back. Unrack the bar and take 1-2 steps back.
5. Set your feet between hip and shoulder width apart. Most people use a narrower stance for front squats compared to back squats.
6. Brace again, inhale, and bend your knees and hips at the same time. Descend as far as you can while keeping your torso upright, your elbows up, and your knees in line with your toes. Do not allow your knees to drop out or fall in. Look straight ahead and not down.
7. Without bouncing out of the bottom, drive your feet into the floor and stand back up. Force your elbows upward as you ascend to stop the bar from rolling off your shoulders.
8. Rerack the bar and rest, or reset your core and repeat if you are doing multiple reps.

Related: Front Squat Hypertrophy Guide – Build Bigger Legs

2. Sissy squat

The sissy squat is the first of our semi-isolation exercises. This classic old-school bodybuilding move definitely emphasizes your quads, but there is a small amount of movement from other joints. However, you’ll definitely feel this one in your quads – there is NOTHING sissy about sissy squats!

How to do it:

1. Stand next to a wall or some other object you can use for balance.
2. Rise up onto your tiptoes.
3. Push your hips and knees forward and squat down as you simultaneously lean back. Descend as far as you can, ideally until your shins are roughly parallel to the floor.
4. Drive your toes into the floor and stand back up.
5. Tense your quads and glutes at the top of each rep and repeat.

3. Heels elevated goblet squat (aka cyclist squat)

While there is no denying that this is a compound exercise, it’s also very quad-centric. In fact, the only muscles you’ll probably feel working are your quads. Raising your heels pushes your knees forward and puts your body in a very upright position. This reduces hamstring and glute activation for a more challenging quad workout.

How to do it:

1. Place two bumper weight plates on the floor about hip-width apart. Alternatively, use a length of wooden plank. Stand with your heels raised and the balls of your feet on the floor.
2. Hold a kettlebell or dumbbell in front of your chest and just below your chin. Pull your shoulders down and back, and brace your core. Look straight ahead.
3. Keeping your torso upright, bend your knees, and squat as deeply as you can without rounding your lower back.
4. Stand up, stopping just short of locking your knees to keep the tension on your quads.
5. Descend again and repeat for the required number of repetitions.

Related: Heels Elevated Goblet Squats Guide

4. Machine hack squat

Most gyms have a hack squat machine. While this IS a compound exercise, it’s also very quad-centric, so you’ll definitely feel this move more in your thighs than your glutes and hamstrings.

The hack squat was one of bodybuilder Tom Platz’s favorite exercises, and he had some of the best quads in history. So, this exercise really does deserve a place in your leg workouts!

How to do it:

1. Stand on the platform with your feet about hip-width apart, toes pointing forward. Put your shoulders under the pads and your back against the backrest. Extend your legs and release the weight safety catches.
2. Bend your legs and squat down, allowing your knees to travel forward. Keep your back pressed into the backrest.
3. Drive your feet into the floor and stand back up.

5. Wall squats

The great thing about wall squats is that you can train your quads hard without using equipment. This is another isometric exercise. If you do this exercise using the technique outlined below, you’ll thrash your quads in under 30 seconds! This exercise is an excellent finisher for a leg workout.

How to do it:

1. Lean your back against a wall and place your feet about two feet in front of you. Slide down the wall until your thighs are about parallel to the floor.
2. Drive your feet forward and down, and push your lower back into the wall as hard as possible. Try to generate as much muscle tension as possible.
3. Keep pushing for 20-30 seconds. If you think you can go for longer, you need to push harder!

Bodyweight and Machine Quad Exercises

You can work your quads conveniently and safely with these thigh-dominant machine and bodyweight leg exercises!

1. Narrow stance leg press

No hack squat? No problem! You can also emphasize your quads by doing narrow stance leg presses. This is a compound exercise, so it works your glutes and hamstrings, too. But, using this technique will put more stress on your quads.

How to do it:

1. Sit on the leg press and put your feet on the footplate, so they are hip-width apart or closer.
2. Extend your legs and flip the weight safety catches to the side.
3. Bend your legs and lower the weight as far as possible without rounding your lower back or straining your knees.
4. Push the weight back up and repeat.

2. Short step lunges

Lunges are an excellent total leg exercise. However, it is possible to emphasize your quads by taking a much shorter than usual step. You can do alternating short step lunges or walking short step lunges as preferred.

How to do it:

1. Stand with your feet together and your arms by your sides. Adopt a good posture and look straight ahead.
2. Step forward about two feet. Bend your legs and lower your rear knee down to the heel of your front leg. Keep your torso upright.
3. Switch legs and repeat.

3. Backward sled drag

Most people view weighted sled training as a conditioning workout. While pushing or pulling a sled will definitely pump up your heart rate and burn a ton of calories, it’s also effective for strength training and muscle-building.

Dragging a weighted sled backward is a knee-friendly way to work your quads and a viable alternative to leg extensions.

How to do it:

1. Stand facing your sled with a handle in each hand.
2. Bend your knees into a quarter-depth squat and walk backward until your arms are straight and the straps are tight.
3. Without bending your arms or leaning forward, walk back while dragging the sled.
4. Push off your toes to maximize quadriceps recruitment.

4. Seated straight leg raise

This quad isolation exercise works the vastus muscles isometrically statically, while the rectus femoris works isotonically to flex your hip. With no movement at the knee to worry about, this is a very joint-friendly quad exercise that’s often used in rehab and prehab situations. However, it may be too easy for some people to be much of a strength or muscle builder.

How to do it:

1. Sit on the floor with one leg bent and one leg straight. Place your hands behind you for balance and support, or lean your back against a wall.
2. Contract the quadriceps of the straight leg and point your toe up toward the ceiling.
3. Lift your straight leg as high as you can without slouching backward.
4. Lower your leg and repeat.
5. Do the same number of reps on both legs.

Frequently Asked Questions

Complications Associated with Quad Isolation Exercises

Hopefully, your quads training will go smoothly, and you’ll get the results you want. However, there are a couple of complications associated with leg training and quad isolation exercises you should be aware of.

Delayed onset muscle soreness

Delayed onset muscle soreness, or DOMS for short, is usually caused by doing more training than usual, working harder than you are used to, or doing new exercises. If you are new to training your quads, it’s very likely that you’ll get some DOMS in your hard-worked muscles.

DOMS typically lasts 24-48 hours after your workout and lasts four to seven days. However, because of something called the repeated bout effect, DOMS usually decreases over a few weeks, and you may not get it much after that.

We’re not 100% sure what causes DOMS, but it may be a combination of lactic acid build-up, muscle microtears, and inflammation. That said, we do know that DOMS is not necessary for muscle growth, so it’s not something you need to train for.

The best way to avoid DOMS is to:

• Warm up before your workout
• Cool down after your workout
• Increase workout duration, volume, and intensity gradually over several weeks, including after layoffs, e.g., vacations.

Read more about DOMs here.

Knee pain

Some quad-centric and quad isolation exercises put a lot of stress on your knees. Sissy squats are an example of this.

If any of the exercises in this article cause discomfort or knee pain, you should choose less demanding exercises, use less weight, or reduce the volume of your workouts. However, in many cases, strengthening your quads could help alleviate knee pain. Strong quads stabilize your knees and reduce joint wear and tear.

Tight quads

Intense strength training can make your muscles short and tight, especially if you don’t do enough stretching. Tight quads can affect your knees AND hips as they cross both of these joints.

The good news is that the quads are very easy to stretch and respond well to flexibility training. Doing a stretch or two after your leg workout will ensure your quads don’t tighten up. Simply standing on one leg and pulling your foot into your butt will give your quads a good stretch.

Check out this guide to the best quad stretching exercises.

Quad Isolation Exercises – Final Thoughts 

There is no denying that squats, leg presses, hack squats, etc., are good lower body exercises, but they work all your leg muscles and not just your quads. For some people, squats and so on are enough to build impressive quads, but others will need to use a more isolation-based approach to training.

Use the nine tried-and-tested quad isolation and emphasizing exercises in this article to build massive, muscular quads. Follow the training guidelines in the FAQ, and you’ll soon be on the way to earning the nickname Quadzilla!

References:

1- PubMed: Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy  https://pubmed.ncbi.nlm.nih.gov/33497853/