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Smith machine split squat: Learn how this Bulgarian leg exercise enables me to build my quads pain-free

By Lee Thomas
Last Updated on 8th November 2020

Did you know, that the Smith machine split squat provides a deeper muscle stretch than just about any other leg exercise?

And did you also know that it's one of the most knee-friendly lower body movements?

The Bulgarian split squat is a special kind of leg exercise. Since your rear foot is elevated, you can go much deeper than you can on regular squats and lunges because the positioning naturally opens up more range of motion at the hip joint.

sportswoman performing lunges

Of course, as any exercise scientist will tell you, more range of motion means more muscle growth, which is why I perform split squats in each and every Smith machine leg workout.

However, there are actually 2 distinct ways that you can utilise the Smith machine for Bulgarian split squats. First of all, you can elevate your foot on a bench and place the Smith bar across your shoulders for resistance (this is the traditional setup for Smith machine Bulgarian squats).

The second way is to use the Smith bar to elevate your rear leg and then hold dumbbells for resistance.

While the traditional Smith machine split squat requires less balance (and thereby enables you to focus purely on working your legs) the second variation is actually much more comfortable. This is because a Smith bar, or a barbell in general, is the perfect shape for the groove of your ankle/foot.

Conversely, when you elevate your rear leg on a bench, you're a lot more unstable, and oftentimes your feet cramp up before your legs are full stimulated.

For the rest of this article, however, I'm going to focus on using the Smith machine for resistance during split squats, as that's what I believe most people are interested in. Nonetheless, most of the benefits and tips apply to all split squat variations, and I hope you'll find this guide useful.

"The Bulgarian split squat is an excellent exercise. Ain’t no denying that!"
Bret Contreras, PhD

Smith machine split squat exercise details

  • Main muscles: Quads, glutes
  • Supporting muscles: Lower back, hamstrings, calves, abs
  • Exercise type: Unilateral
  • Difficulty: Intermediate
  • Equipment needed: Smith machine, weight bench
  • Recommended gear: Knee sleeves, BFR wraps, foam roller
  • Exercise purpose: Build more muscular quads and glutes

How to do Bulgarian split squats on the Smith machine

  1. Place a weight bench just behind the Smith machine, so that when you're in the split squat position, the bar is directly above your upper traps. You'll most likely have to experiment with the bench position to line the bar up properly. So you needn't worry if you don't get things right the first time.
  2. Elevate your strongest leg onto the bench by placing either your midfoot or toes onto the padding. Try both and see which is the most comfortable.
  3. Take a large step away from the bench—about 2 feet long—with your other foot and plant it firmly on the ground. Use a shorter step to emphasise your quads or a longer one to emphasise your glutes.
  4. Ensure that your spine is in neutral and that your eyes are looking straight ahead.
  5. With most of the pressure on your front leg, descend by breaking at the hips and bending at the waist slightly as you lower yourself towards the ground*
  6. Squat down until the knee of your back leg touches the floor (or until your lower back starts to round). Both are reliable indications that you've gone deep enough.

*Note that you should still maintain a neutral spine when you bend at the waist. Don't let your lower back round. Otherwise, your shoulders will cave in. This is a big no-no because it takes tension off your quads and places it onto your weaker spinal erectors instead.

Smith machine split squat mistakes

Breaking at the knees first

close up of a bodybuilder's quadriceps

Want a surefire way to put yourself on the waiting list for an early-life knee replacement?

Then look no further than the split squat. And specifically, breaking at your knees first during the descent.

Now, I'm not telling you to avoid bending your knees—that would turn the exercise into a good morning.

However, I am strongly recommending that you squat down by breaking at your hips and bending at the waist, as this takes the pressure off your joints by ensuring proper knee tracking.

And that's to say nothing of the fact that such form provides a much larger range of motion (ROM). Isn't it amazing how the proper form also produces better results?

Stepping out too far

man instructing a woman while she works out

It's a well-known fact that performing split squats with a long stride increases glute activation. Unfortunately for their gains, many people take a long stride to means the longest possible stride, and I think you can guess how I feel about that.

Sure, you'll get a great pump in your glutes, and a phenomenal stretch in the quadricep of your back leg by split squatting like this. However, such form significantly reduces your ROM (and thereby muscle growth) and is essentially the one-legged version of half squatting.

Turning it into a good morning

powerlifter squatting heavy

You wouldn't believe me the way that some people do it, but the split squat is actually a leg exercise.

While I can definitely appreciate wanting to keep the stress off your knees, bending at the waist isn't an excuse to turn your squat into a good morning.

As a rule of thumb, your hips and knees should rise together. If your hips shoot up first, then you either need to lighten the weight or work on your form. Probably both. So train your legs, not your ego.

Recommended training gear for Smith machine split squats

"Do you need knee sleeves? No. But they are very beneficial."
Ryan Healy, BSc
Coach and Personal Trainer

1. Knee sleeves

man doing squats in his beast gear knee sleeves

Whether I do the Bulgarian split squat Smith machine style or with free weights, I don't lift without my Beast Gear Knee Sleeves.

I used to be that old-school lifter who believed that all gym accessories were for weaklings (although my choice of wording was a little more colourful than that).

Rymora sleeves

Anyway, since I've become older, wiser and stronger, I've started to appreciate the many benefits of wearing knee sleeves. Besides making my knees feel more secure, they also enable my leg muscles to recover faster because they naturally reduce cell swelling and promote blood flow via compression.

I enjoy that satisfaction of DOMS as much as the next person, but it's great to be able to get back in the gym sooner, instead of hobbling around at home.

If you're on a budget, then these Knee wraps are also a good choice. My wife uses them for squats, and she has no complaints.

2. BFR wraps

Occlusion cuffs (or blood flow restriction wraps) are the training tool that I wish I knew about 10 years ago.

man wearing occlusion cuffs while training his arms

Essentially, BFR wraps enable you to use really light weights—30-40% of your 1RM—and achieve the same, if not better results, than lifting heavy iron. Obviously, this is great for your joints because they take much less of a beating. But it's also a brilliant training technique for speeding up your recovery because it causes way less muscle damage, meaning that you can lift more often.

I use the BFR training bands for my arms, and they give me a wicked pump that not even drop sets can replicate.

For my legs, I use these Floss Bands.

While they're not dedicated occlusion cuffs, I find that they work excellently for legs because they allow you to really customise the tightness.

Well worth the investment and much cheaper than any so-called "nitric-oxide supplement".

"If you're strength training or you're an athlete in any way, shape, or form, you have to get some sort of tissue work done. You either need to go to a neuromuscular therapist, massage therapist, or you gotta do it yourself."
Elliott Hulse
On Foam Rollers

3. Foam roller

a black fit nation foam roller

As effective as split squats are for packing on mass, they're tough to recover from (if you do them right) because they cause so much muscle damage.

I've been foam rolling after every leg session, and besides reducing my mental stress, it's made a world of difference in my recovery, especially since I also wear knee sleeves.

fit beast foam roller set

Since I love trying new fitness equipment, I bought this Foam Roller 4 Piece Set because it comes with other goodies like a massage ball, which is great for getting knots out of your back.

I also have a Trigger Point Foam Roller (which I bought ages ago and never used until recently). It's great for loosening up your muscles before or after a session, and it also comes with a money-back guarantee, so I figured that I had nothing to lose!

Smith machine split squat muscles worked


Illustration of the gluteus maximus anatomy

The Smith machine single leg split squat is one of the best glute exercises that you can do for mass.

Don't get me wrong, cable kickbacks are nice. In fact, my wife does them all the time. But nothing puts "mass on your ass" like heavy squats that stretch the glutes. And it's split squats, more so than barbell squats, that really stretch the glutes and break down the muscle tissue.


Illustration of the quadriceps anatomy

Keeping your front foot closer to your centre of gravity emphasises your quads because it allows for more ROM at the knee joint. However, such a stance also means that you have to lean forwards more to avoid having your knees go too far over your toes. So, as always, keep your stride length within reason to avoid injuries.


Illustration of the spinal anatomy

The more that you bend at the waist, the more active your spinal erectors become. This is simply because their primary function is to regulate your spine's flexion and extension. And in the case of split squats, to keep your spine in neutral.


Illustration of the hamstring anatomy

Since split squats necessitate that you bend at the waist to achieve a full ROM, it's no surprise that research shows that they active more hamstring muscle fibres than back squats [1]. This extra activation is because you're in deeper hip flexion, which is one of the hamstrings' two major functions (the other being knee flexion).


Illustration of the abdominal anatomy

Since training one leg at a time naturally creates more instability than two-legged squats, you'll get a decent core workout while performing Smith machine split squats. Even if (as with any type of Smith machine squats) the machine does do most of the stabilising for you.

Smith machine split squat benefits

Less lower back strain

woman with her hands on her back because she is in pain

Despite requiring more balance and stability, research shows that Bulgarian split squats actually place less pressure on your spine than traditional back squats [2]. And that's with free weight split squats, so just imagine how much more lumbar strain the Smith machine removes!

My theory is that because you're training unilaterally, and inherently using less weight than on a bilateral exercise, your lower back is simply subjected to less stress, and therefore, your spine stays healthier.

Bigger quads and glutes

a close up of a female bodybuilder's quadriceps

Which leg exercise provides the deepest muscle stretch?

If you answered "Bulgarian split squats", then you'd be correct [3].

Since your rear foot is elevated, you can naturally get a deeper stretch in your front glute muscle because your hips start in a higher position, and thus, have more distance to travel.

And if you perform a Smith machine deficit split squat—with your front foot elevated—then your quadriceps will enjoy the same advantage, and you'll reap the rewards in bigger, more defined legs.

This is because the stretch part of a rep is much more important than the contraction for muscle growth [4].

Reduced knee pain

man with knee pain sat down in the gym

Although it's a favourite excuse of many so-called "bodybuilders" who skip leg day, knee pain during squats is as real as the food on your plate. Unless, of course, your food was made in a lab.

But that's a topic for another time.

The reality is, many people can't build their legs with squats because they can't lift enough weight—pain-free—to trigger new growth.

Enter the Smith machine single leg split squat...

Since split squats naturally allow for much more hip flexion than back squats, you can descend far deeper, and hence, stimulate faster muscle growth, without compromising your knee health [5].

It's as if humans are meant to train one leg at a time...

Smith machine split squat alternatives

Check out these alternatives to smith machine Bulgarian split squats if you want to fix your muscle imbalances.

Smith machine lunge

sportswoman doing a lunge exercise

Performing weighted Smith machine lunges is a brilliant way to hammer your quads without taxing your knees because your feet are already firmly planted on the floor. In other words, the kinetic chain—to be scientific—is closed rather than open, which transfers less stress through your joints because they're in a relatively fixed position.

Smith machine reverse lunge

young man and woman working out in the gym

Likewise, Smith machine reverse lunges are an excellent movement for bringing up lagging quads and glutes without frying your patella. Since this exercise naturally recruits more of your gluteus maximum muscle fibres, you can lift heavier weight and potentially build more size than with any other lunge or squat variation.

Smith machine step up

man doing lunges on a step up box

As with the lunge and reverse lunge, Smith machine step ups are ideal for improving your muscle imbalances because you're training each leg individually.

However, in my experience, they place more strain on your knees than the likes of the Smith machine split squat because they're a very quad-dominant movement.

Lee Thomas
Ey Up! I'm Lee, a Leeds-based strength and conditioning coach who's been helping serious trainees achieve their physical potential for the past 20 years. In my time, I've been a competitive physique athlete and a national powerlifter. I hope you enjoy my exercise guides.
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