Box Bulgarian Split Squat

Also known as: box split squat, bulgarian split squat with box, bulgarian split squat on box

In SetGrip: Bulgarian Split Squat (Box)

Secondary muscles
Quads, Hamstrings, Calves
Body part
Upper Legs
Position
Standing
Laterality
Unilateral (one leg at a time)
Category
Strength

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Loading one leg at a time makes each side earn its own reps, exposing the strength and balance gaps that two-legged squats hide. Keep sets at 6-10 per side with a slow, even descent, and add dumbbells only once bodyweight reps look identical on both legs.

How to do the Box Bulgarian Split Squat

  1. Stand with your feet shoulder-width apart.
  2. Extend one leg forward, keeping it off the ground.
  3. Bend your standing leg and lower your body down as if sitting back into a chair.
  4. Keep your chest up and your back straight.
  5. Push through your heel to return to the starting position.
  6. Repeat with the other leg.

Tip: Screw the feet into the floor and spread it apart to keep the knees out and the arch of the foot from collapsing.

Muscles worked

Primary

Glutes · Legs

The glutes extend the hip on the way up and take more of the load the deeper you go and the wider your stance.

Secondary

  • Quads — The quads extend the knee and drive you out of the bottom, and front squats and close stance variations put more on them.
  • Hamstrings
  • Calves

Common mistakes

  • Knees caving inward — push the knees out over the toes on the way up, especially out of the bottom where they most want to collapse.
  • Hips shooting up first — if the hips rise faster than the chest on the way up, you turn the squat into a good morning; drive the chest and hips up together.
  • Cutting the depth — get the hip crease below the top of the knee on every rep unless mobility genuinely stops you, in which case work on it.
  • Losing the brace — take a big breath into the belly before each rep and hold it through the sticking point, then exhale on the way up.

Sets, reps and where it fits

GoalSets × repsRest
Strength4–5 × 3–6 per side2–3 min
Muscle growth3–4 × 6–12 per side90–120 s
Endurance2–3 × 12–20 per side60 s

Squats go first in a lower body session when you are freshest. Follow them with Romanian deadlifts or leg press, or superset lighter sets with pull-ups to use the same rack.

Variations and alternatives

Similar exercises

Without bodyweight

Easier and harder

Frequently asked questions

What muscles does the Box Bulgarian Split Squat work?

The Box Bulgarian Split Squat primarily works the glutes. It also involves the quads, hamstrings and calves, which assist the movement and stabilise the joints.

Is the Box Bulgarian Split Squat good for beginners?

Not as a starting point. The Box Bulgarian Split Squat is rated advanced because it demands strength, mobility or coordination that takes time to build. Beginners should work up to it through the easier variations listed on this page.

What can I do instead of the Box Bulgarian Split Squat?

If you cannot do the Box Bulgarian Split Squat, try the Dumbbell Pistol Squat, the Kettlebell Pistol Squat or the Pistol Squat. Each of them trains the glutes through a similar movement, so you can swap them in without changing the rest of the workout.

How many sets and reps should I do?

It depends on your goal. For the Box Bulgarian Split Squat, a sensible starting point is strength: 4–5 × 3–6 per side with 2–3 min rest; muscle growth: 3–4 × 6–12 per side with 90–120 s rest; endurance: 2–3 × 12–20 per side with 60 s rest. Put it early in the session while you are fresh, before isolation work for the same muscles.

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Exercise data and animations are licensed ExerciseDB content used in SetGrip. This page is for general information and is not medical or coaching advice.