The Bulgarian split squat is a split squat with your rear foot raised on a bench, so the front leg does most of the work. The back squat is the usual two-legged lift with a barbell on your upper back. Lifters ask which one to build a leg day around, and the answer depends on what you are trying to improve.
We checked the primary studies rather than gym folklore, and the evidence is smaller than the confident claims online suggest. This article covers what five studies found, where they stop, and how to keep your training record clean when you rotate between the two lifts.
Is the Bulgarian split squat better than the back squat?
Neither is better on the evidence we found. The studies compare them on joint loading, muscle activity and short-term strength, and the results are mostly "similar" with a few specific differences. None measured muscle growth head to head.
The practical differences are easier to see than the proven ones. The back squat lets you move the most total load and trains both legs at once. The split squat takes the bar load down, puts one leg at a time under the weight, and asks more of balance. Our guide to unilateral vs bilateral training covers that wider trade-off.
If you are choosing between them, the useful questions are which one you can progress steadily, which one your joints tolerate, and whether you compete in a barbell squat. We come back to that in the decision table below.
What does the research say about Bulgarian split squat vs squat?
Five small studies are the core of it. One compared joint loading, one compared muscle activity, one tracked glute activity across several lifts, one ran a five-week training trial, and one looked at differences between legs. All used trained men or athletes, so they say little about other groups.
Joint loading. Mackey and Riemann (2021) tested 20 resistance-trained men. They performed 2 sets of 3 reps of back squat at 70% of their 1RM and Bulgarian split squat at 35% of their back squat 1RM. Both lifts were hip-dominant: hip joint moment, work and impulse were greater than at the knee or ankle. Knee joint peak displacement was significantly lower in the split squat, while ankle and hip displacement were similar. In the back squat, knee work was greater than ankle work, but in the split squat the two were similar. The authors suggested the split squat suits hip extension work with less knee demand, such as early knee rehabilitation.
Muscle activity. DeForest et al. (2014) tested 9 resistance-trained men on a back squat at 85% of 1RM, plus a rear-leg-elevated split squat and a standard split squat at 50% of the back squat load. Muscle activity was similar across the exercises, except the biceps femoris (a hamstring muscle). It was higher in the rear-leg-elevated split squat than in the standard split squat, and higher in the back squat than the standard split squat. The study did not report a back squat versus rear-leg-elevated split squat difference there. Peak vertical force was similar for those two.
Glute activity. Williams et al. (2021) measured gluteus maximus activity in 12 male team-sport athletes at their 3-rep max. Peak activity was higher in the barbell hip thrust than in the back squat or the split squat. The study did not report a significant back squat versus split squat difference. If glute work is the aim, our comparison of the hip thrust vs squat goes further.
Training trial. Speirs et al. (2016) randomised 18 academy rugby players into two groups for 5 weeks, training twice a week at a relative percentage of 1RM. One group squatted only with the rear-elevated split squat, the other only with the back squat. Both groups improved on 1RM back squat, 1RM rear-elevated split squat, 40 m sprint and pro-agility, with no significant group by time interaction. The 10 m sprint did not change significantly. The authors concluded the two approaches were equally effective for these outcomes in this group.
Differences between legs. Lockie et al. (2017) had 8 men perform a 5-rep-max Bulgarian split squat with a linear position transducer. Dominant and non-dominant legs differed significantly in 11 of 12 power, force and velocity variables, but the percentage differences were small, roughly 0.3 to 12%. That shows the split squat can reveal a gap between legs, though the study cannot say whether closing it matters.
| Question | What the evidence shows | Limit |
|---|---|---|
| Joint loading | Both hip-dominant; less knee displacement in split squat | 20 men, one session, not growth |
| Muscle activity | Mostly similar; hamstring differences depend on which split squat | 9 men, EMG only |
| Strength | Equal 1RM gains after 5 weeks of either lift | 18 rugby players, short trial |
| Muscle growth | No direct trial found | Do not assume equal |
| Between-leg gaps | Split squat can expose them | 8 men, link to performance unclear |
Does the Bulgarian split squat build as much muscle or strength?
For strength, probably similar in the short term, based on one small trial. For muscle growth, we do not know. Speirs et al. measured strength and speed rather than muscle size, and the other studies measured activity or joint mechanics.
That gap matters because EMG and joint moments describe how a lift loads the body, not how much tissue you add. A higher activation reading in one muscle does not mean more growth in that muscle, and a lower knee load does not mean lower quad growth.
Two things about the strength result are worth holding onto. It lasted only 5 weeks in young, trained athletes, so we cannot say how it plays out over a year. And it shows the split squat group improved their back squat without ever training it. That carry-over is a point in the split squat's favour, but it does not show the split squat beats the back squat.
Our reading, not a finding: since both lifts load the hip heavily and the quads meaningfully, a lifter who uses either one with hard sets and steady progression has a reasonable chance of getting stronger. The better question is which one you will actually progress.
What do the two lifts load differently?
The clearest difference in the data is knee demand, with hip demand similar. Beyond that, the muscle activity results are mostly similar across the lifts, so be wary of claims that one lift "targets" a muscle the other misses.
- Knee. Mackey and Riemann found significantly lower knee joint peak displacement in the split squat, at a much lighter relative load. The back squat had knee work greater than ankle work, and the split squat did not.
- Hip. Both lifts were hip-dominant, with similar hip displacement.
- Hamstrings. DeForest et al. found biceps femoris activity depended on the version: raising the rear foot raised it compared with a standard split squat.
- Glutes. Williams et al. found the hip thrust, not either squat, produced the highest peak glute activity.
- Balance. The split squat is a one-leg lift, so stability limits what you can load. We could not find a study that measured this directly, so treat it as our judgement.
If your concern is how the back squat itself changes with setup, our squat stance width and front squat vs back squat guides cover the options. For machine-based leg work, see leg press vs squat and hack squat vs back squat.
Which should you choose?
Choose by your goal and your constraints. The table below is our practical judgement built on the studies above, not a result from any of them.
| Your situation | Suggested starting point |
|---|---|
| You compete in a barbell squat sport | Keep the back squat as the main lift; add split squats as accessory work |
| Your knees complain under a heavy back squat | Try split squats at a lighter load, and get persistent pain assessed by a clinician |
| You train at home with dumbbells and a bench | Split squats work well, since the load is lighter |
| You suspect one leg is weaker | Split squats make a gap visible; log both sides |
| A back squat max is stalling | Rotate in split squats for a block, then compare against your history |
| You want the largest possible total load | Back squat |
None of these rows is proven in a trial. Treat each as a hypothesis to test against your own log. If you do both in the same week, count the sets from each toward your weekly leg volume.
How should you load and progress each lift?
Progress each lift on its own history and use effort to judge sets, not the plate count. The load you can handle on a split squat is much lower than on a back squat, so the two numbers do not belong on the same scale.
The load gap is built into the research. Mackey and Riemann used 35% of back squat 1RM for the split squat and 70% for the back squat, which suggests lifters work at roughly half the relative load. It is not a rule for your own training, since your rear-foot height, stance and dumbbell or bar choice all change what is possible.
Three simple approaches work for both lifts:
- Double progression. Pick a rep range such as 8 to 12 and add reps at the same load until every set reaches the top, then add load. Our double progression guide has the steps, and it suits the split squat well because dumbbells change in small jumps.
- Reps in reserve. Stop each set a planned number of reps short of failure and record it. A split squat at 2 RIR and a back squat at 2 RIR are comparable in effort even though the loads are not. Our RIR guide explains how to rate a set.
- Heavy top set, lighter work after. Use the back squat for heavy practice and the split squat for moderate-rep volume, as one example weekly pattern of ours rather than a tested plan.
Set up consistently. Keep the rear-foot height, front-foot distance and depth the same from week to week, so a change in the number reflects you and not the setup.
How do you log Bulgarian split squats and squats in IronLedger?
Log them as two separate exercises with load, reps and RPE or RIR on every set, and judge each against its own history. IronLedger is a free iOS strength training app (Android is in closed testing) that keeps your full training history with no cutoff.
What the app records, per its product page:
- Per-set fields. Load, reps, RPE in half steps or RIR, and a free-text note on the set.
- Estimated 1RM and records. IronLedger uses the Epley formula, weight x (1 + reps / 30), and tracks personal records per lift. A 100 kg set of 5 gives an estimate of 116.7 kg. Our estimated one-rep max guide covers its limits, and trends sit on the progress page.
- Mid-session swaps. If the bench is taken you can replace the exercise while the workout is running.
IronLedger has no field for which leg you trained or for rear-foot height, so use a convention of your own. Three habits that work:
- Choose one load rule and keep it. For dumbbells, log the weight in one hand. For a bar, log the bar load. Write which rule you used in the first note.
- Use the note for setup. Something like "rear foot on 45 cm bench, left leg first" keeps the lift comparable over time.
- Log reps you did on the weaker leg. If one side gives out sooner, stop both sides at that rep count, or note the difference. Lockie et al. found small but significant gaps between legs, so a consistent rule makes any gap visible.
Do not add split squat kilograms to back squat kilograms. Your workout history is more useful with each lift on its own line.
What mistakes should you avoid?
Most mistakes come from reading too much into a small study or treating the two lifts as interchangeable. Judge each lift by its own trend and let effort show whether a set was hard.
- Claiming equal muscle growth. No trial we found measured it for these two lifts.
- Comparing loads across the lifts. A smaller split squat number does not mean a weaker lifter. The research used about half the relative load.
- Reading EMG as growth. Higher activation in one muscle in one test is not a growth result.
- Generalising from rugby players. The only training trial ran 5 weeks in 18 young athletes.
- Changing the setup mid-block. A different rear-foot height or stance is a different lift. Note it, so the history stays honest.
- Ignoring pain. Persistent knee, hip or back pain needs assessment, and no comparison article can replace it.
Frequently asked questions
We found no study showing that. Both are hip-dominant, the split squat showed less knee displacement, and a 5-week trial found similar strength gains from each. No trial compared muscle growth.
Sources and references
- Mackey and Riemann, Biomechanical Differences Between the Bulgarian Split-Squat and Back Squat — 20 trained men; both hip-dominant, with less knee displacement in the split squat (Int J Exerc Sci, 2021).
- DeForest et al., Muscle Activity in Single- vs. Double-Leg Squats — 9 trained men; similar muscle activity apart from biceps femoris differences (Int J Exerc Sci, 2014).
- Williams et al., Activation of the Gluteus Maximus During Performance of the Back Squat, Split Squat, and Barbell Hip Thrust — peak glute activity was highest in the hip thrust among 12 athletes (J Strength Cond Res, 2021).
- Speirs et al., Unilateral vs. Bilateral Squat Training for Strength, Sprints, and Agility in Academy Rugby Players — 18 players; no group differences after 5 weeks (J Strength Cond Res, 2016).
- Lockie et al., Between-Leg Mechanical Differences as Measured by the Bulgarian Split-Squat — 8 men; small but significant between-leg differences (Sports, 2017).
- IronLedger product page — per-set RPE and RIR, set notes, estimated 1RM, personal records and exercise replacement.
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