Bulgarian Split Squat: How to Do It, Muscles Worked, and Programming Guide

The Bulgarian split squat (BSS) is a single-leg squat performed with your rear foot elevated on a bench or box behind you. Your front leg handles most of the load, making it one of the most effective exercises for building quad and glute strength — and for fixing the leg asymmetries that bilateral squats quietly ignore.

It is also called the rear-foot-elevated split squat (RFESS). Both names refer to the same exercise.

What muscles does the Bulgarian split squat work?

The BSS is primarily a quad-dominant exercise. A 2025 study in BMC Sports Science (Aygun-Polat et al., n=21 trained female athletes) measured muscle activation across four BSS variations and found:

• Rectus femoris reached 75.91% MVIC in the forward-trunk condition versus 52.22% in the upright position
• Gluteus maximus activation increased from 16.25% (upright trunk) to 21.32% with forward lean — meaning trunk position directly controls how much glute you recruit

A second 2025 study in Scientific Reports (Topçu et al., n=23 male soccer players) found that gluteus maximus activation was approximately 130% higher during the ascent phase than during the descent. Focus on driving hard out of the bottom, not just lowering under control.

Practical takeaway: upright torso means more quad focus. Leaning forward 20–40° from vertical means more glute and hamstring recruitment. Decide based on your training goal.

Secondary muscles recruited: biceps femoris (hamstrings), adductors, hip flexors of the rear leg, erector spinae and core stabilizers.

Bulgarian split squat versus back squat — what is the difference?

This question comes up constantly. The short answer: they do different things.

A 2021 biomechanics study in the International Journal of Exercise Science (Mackey and Riemann, n=20 trained males, PMID 34055144) compared BSS and back squat directly. Peak knee flexion was 9.2° lower in the BSS than the back squat. The hip is the primary driver in both exercises, but the knee demands differ significantly. The authors note the BSS is well-suited to emphasizing hip extension while minimizing knee joint stress.

A 2025 study in the International Journal of Exercise Science (Arakawa et al., PMID 40909869) added a mechanistic insight: the rear leg generates 62–98% of total hip extension resistance during the BSS, ranging from 70–97 Nm depending on stance width. Even in a bodyweight BSS, the rear leg contributes a large resistive moment — you are not just passively resting the foot on the bench.

The BSS is not a back-squat substitute. It is a complementary exercise that emphasizes unilateral hip extension, reduces spinal compression, and reveals imbalances between legs. Use both in a well-structured program.

How to do the Bulgarian split squat

Setup

1. Stand about 60–70 cm in front of a bench or box (roughly one shin's length away)
2. Place your rear foot on the bench, laces down or toes tucked — both work; find what feels stable
3. Your front foot is flat on the floor, toes pointing forward or very slightly outward

The movement

1. Lower your body straight down until your front thigh is roughly parallel to the floor, or as far as hip and knee mobility allows
2. Keep your front knee tracking over your second or third toe — avoid caving inward
3. Drive through your front heel to return to the starting position

Trunk position controls the target muscle

• Upright torso (chest tall, minimal forward lean): shifts emphasis to quads
• Forward lean of 20–40° from vertical: shifts emphasis to glutes and hamstrings

Start with an upright torso and bodyweight until the movement is stable, then adjust lean based on your training goal.

Common mistakes

Bench too high. The rear foot should sit just high enough to allow your front knee to reach a 90° angle. A standard flat bench at 43–45 cm is usually correct. Too high and you lose stability; too low limits range of motion.

Front foot too close. If your front knee shoots far past your toes when you lower, move the front foot forward. The knee tracking over the toes is not dangerous per se, but excessive forward tracking under heavy loads can increase patellofemoral stress.

Collapsing the rear knee toward the floor. The rear leg is contributing resistive force (Arakawa et al. 2025), not just resting. Keep some tension in the rear hip flexor rather than letting the knee drop passively.

Loading too fast. The BSS with dumbbells or a barbell on your back is a technical exercise. Progress through bodyweight → single dumbbell held goblet-style → dual dumbbells → bar, in that order.

Programming the Bulgarian split squat

Sets and reps

For hypertrophy: 3–4 sets of 8–12 reps per leg at a load that brings you close to failure by the final rep (roughly 65–75% of your estimated 1RM equivalent).

For strength: 4–5 sets of 4–6 reps per leg at a heavier load (80–85% 1RM equivalent).

For beginners and technique work: 3 sets of 10–15 reps per leg with bodyweight or a light dumbbell held at the chest.

Work one leg fully before switching. This maintains effort quality per leg compared to alternating.

Frequency

Two sessions per week covers most training goals. Because the BSS creates significant quad and glute fatigue, allow at least 48 hours between sessions targeting the same muscles.

How to apply progressive overload

Once you consistently hit the top of your rep range with clean technique, add load. For dumbbells, increase by 2 kg per hand. For a barbell, increase by 2.5–5 kg per side. Track load and reps per leg — left-right asymmetry often hides in untracked workouts. See our full guide on progressive overload for the complete framework.

Where to place it in your week

The BSS fits best early in a lower-body session, after your barbell squat if you are squatting that day, or as the primary leg exercise if you are not. Do not place it after heavy hamstring work when the stabilizing leg is already fatigued. For a complete lower-body session structure, see our leg day guide.

Using the Bulgarian split squat to address muscle imbalances

Most people have one leg that is measurably stronger than the other. Bilateral exercises like the back squat allow the dominant leg to compensate. The BSS forces each leg to work independently.

A practical test: perform 5 BSS reps on your left leg and 5 on your right with the same load. If one side struggles or moves differently, that is your imbalance. Track per-leg loads over time and close the gap before it becomes a chronic compensation.

Frequently asked questions

What does the Bulgarian split squat work the most?

The quads are the primary target, with gluteus maximus and hamstrings as secondary muscles. Trunk position controls the ratio: lean forward for more glutes, stay upright for more quad.

Is the Bulgarian split squat good for glutes?

Yes, especially during the ascent. The 2025 Topçu study found gluteus maximus activation is about 130% higher during the ascending phase than the descent — focus on driving through the heel as you rise. Forward trunk lean further increases glute recruitment (Aygun-Polat et al. 2025).

How many reps per set?

For hypertrophy: 8–12 reps per leg per set. For strength: 4–6 reps per leg. Beginners should aim for 10–15 bodyweight reps before adding load.

Is the Bulgarian split squat harder than a regular squat?

Most trainees find it harder initially because of the balance demand. The actual load is lower (typically 60–70% of what you can back squat), but the localized effort per leg is higher.

Can I do BSS if my knees hurt?

The BSS has lower peak knee flexion demands than the back squat (Mackey and Riemann 2021). Start with bodyweight and a shorter range of motion. If pain increases rather than decreases over 2–3 sessions, stop and consult a clinician.

The Bulgarian split squat in a complete training program

The BSS fits into any well-designed muscle gain program as a primary or secondary lower-body exercise. Pair it with hip hinge movements — Romanian deadlift, hip thrust — to cover both knee-dominant and hip-dominant patterns in the same session.

Compound unilateral exercises like the BSS create a significant muscle protein synthesis stimulus per session. Sleep and recovery directly limit how much of that stimulus converts to muscle. See our sleep and muscle growth guide for why 7–9 hours per night is a training variable, not a lifestyle suggestion.

Sources

• Aygun-Polat E et al. (2025). Targeted muscle activation in Bulgarian split squat variations: effects of trunk position and suspension-based execution. BMC Sports Sci Med Rehabil. PMC12382192, PMID 40867012.
• Topcu H et al. (2025). Effects of rear-foot instability devices on lower-limb muscle activation during the Bulgarian split squat in male football players. Scientific Reports. PMC12819420, PMID 41392178.
• Mackey ER, Riemann BL. (2021). Biomechanical Differences Between the Bulgarian Split-Squat and Back Squat. Int J Exerc Sci. PMC8136570, PMID 34055144.
• Arakawa H et al. (2025). Rear Leg-derived Moment Contributes to Resistance Against Hip Extension in Bulgarian Split Squats. Int J Exerc Sci. PMID 40909869.