The Cossack Squat: A Complete Guide From First Rep to Advanced Variations

Quick Intro

The Cossack squat is a lower-body exercise performed by shifting the weight deep to one side, bending that knee into a full squat while the other leg stays straight and the heel stays flat, then pushing back to center.

Equipment Needed

A Cossack squat asks for nothing more than floor space wide enough to shift fully to one side and back.

Why the Cossack Squat Matters

The Cossack squat asks the inner thigh (adductors) of the straight leg to lengthen through a deep range while the glutes (gluteus maximus and gluteus medius) and front of the thigh (quadriceps, rectus femoris) of the bent leg absorb the full weight of the body, and the hip flexors guide the transition through the bottom of the shift. Taking the lateral lunge’s sideways step and dropping it all the way to a full squat depth is what turns this into as much a hip mobility drill as a strength exercise.

That combination is the reason this movement holds a place of its own, not just a deeper version of a familiar step. A standard lateral lunge stops well short of full squat depth, keeping the hip and ankle ranges modest even as the inner thigh stretches. The Cossack squat pushes that same sideways shift down to the floor, asking the ankle, hip and groin to open through a range few other lower-body exercises reach at all.

The Cossack squat is a demanding flexibility exercise for the hips and inner thighs first, training a deep, controlled range most daily movement never asks for. Balance comes next, from controlling the shift at depth, with strength and endurance work for the glutes and quads alongside.

When to Do It

The Cossack squat fits well in a lower-body or mobility-focused session, ideally once the hips are already warm from lighter movement. Two to three sessions a week gives the hips and knees time to adapt to the depth between sessions.

• Limited ankle or hip mobility. The bottom position asks for more ankle bend and hip opening than most other squat variations. Starting with a shallower depth, or a rolled towel under the heel of the bent leg, is the safer approach until that range builds naturally.

For most people without a specific ankle or hip restriction, this is a valuable way to build strength through a range most training never touches.

Getting Ready

A minute of hip circles and a few bodyweight squats warm up the hips and ankles before asking them to control a full range shift from side to side.

Keep the straight leg’s heel and toes pinned flat to the floor throughout the shift. The depth achieved should come from hip mobility, not from letting that heel lift or the bent knee cave inward.

Step-by-Step Instructions

1. Starting position. Stand with your feet set wide apart, toes turned out slightly, hands clasped in front of your chest or reaching forward for balance.

2. The shift. Shift your weight to one side, bending that knee into a full squat while keeping the other leg straight, its heel and toes flat on the floor.

3. The return. Push through the bent leg to shift your weight back through center, either standing fully or continuing straight into the shift on the other side.

Move at a controlled pace throughout, treating the full range at the bottom of each shift as the point of the exercise, not something to rush past.

How Many, How Often

Letting the straight leg’s heel lift off the floor is the easiest way to fake extra depth while quietly borrowing range from the ankle that’s supposed to be building it honestly, so keeping that heel pinned down matters more here than how low the shift reaches.

Modifications and Variations

The Cossack squat connects to two branches, one an easier entry point and one a different unilateral alternative.

For an easier entry point, the Lateral Lunge keeps the same sideways shift at a shallower depth, building the pattern before asking for a full squat at the bottom.

As a different unilateral alternative, the Pistol Squat drops the working leg straight down, asking for a similar depth of hip and knee bend through a forward plane rather than a lateral one.

Progression path: Lateral Lunge → Cossack Squat

Widening the stance before the shift, or slowing the descent through the bottom third, are reasonable ways to add difficulty within this exercise before moving to a different unilateral pattern.

Common Mistakes to Avoid

Letting the straight leg’s heel lift off the floor. A lifted heel borrows range from the ankle instead of building hip and groin mobility, which is the training effect this exercise is after. Keep that heel pinned flat throughout the shift.

Letting the bent knee cave inward. A knee that drifts toward the midline places uneven strain on the joint and pulls load away from the hip and thigh muscles that should be handling it. Tracking the knee in line with the toes preserves the intended demand.

Rushing through the shift without pausing at depth. Bouncing quickly through the bottom skips the range the hips and inner thigh need to work through. Moving slowly and controlling the full shift keeps each rep meaningful.

Leaning the torso too far forward. Tipping forward at the bottom shifts weight off the working leg, turning the squat into a lean and losing the controlled shift the exercise depends on. Keeping the chest reasonably upright and the weight centered over the bent leg’s foot keeps the demand where it belongs.

After Your Set

Dropping to full depth on each side asks more of the hips and groin than most squat patterns reach, and that range is worth releasing deliberately afterward. Sitting on the floor with the soles of the feet pressed together and the knees dropped wide opens the groin through the same plane the shift just worked. A slow standing forward fold afterward, hinging at the hips with the knees soft, releases the back of the legs that helped anchor every shift.

Going Deeper

The lateral lunge usually leads into the Cossack squat, once that movement feels comfortable and a full drop to squat depth on one side starts to feel achievable. Opening a warm-up with a hip-opening drill like a standing figure-four stretch primes the same range this exercise goes on to load.

What caps depth here early on is rarely leg strength alone. It’s usually the ankle and hip running out of range before the muscles do, since the shift asks for more joint opening than most people have built through other training. Working on ankle and hip range separately, outside the squat itself, tends to unlock more depth than simply attempting the movement more often.

Someone with a solid lateral lunge already can expect five clean reps per side at a shallower depth within the first two to three weeks, and ten reps per side reaching full depth somewhere in the six to eight week range.

How to Know You’re Improving

1. Five clean reps per side at a shallower, comfortable depth
2. Ten reps per side reaching full depth with the straight leg’s heel staying flat
3. Twelve reps per side in a row with no knee cave and no torso lean
4. A held pause of two seconds at full depth on every rep

A rep counts as clean when the straight leg’s heel never lifts, the bent knee tracks over the toes and the torso stays reasonably upright through the whole shift. How consistently that depth is reached on both sides matters more than total rep count on its own.

Muscles Worked

• Adductors (the inner thigh muscles, stretching on the extended leg while the other side squats)
• Gluteus Maximus (the largest glute muscle, driving the bent leg back up to standing)
• Gluteus Medius (a smaller glute muscle at the side of the hip, controlling the deep sideways shift)
• Rectus Femoris (one of the quadriceps at the front of the thigh, holding the working knee through a very deep range)
• Iliopsoas (the deep hip flexor at the front of the hip, keeping the torso upright over the bent leg)

FAQ

What makes the Cossack squat different from a lateral lunge? The Cossack squat takes the same sideways shift down to a full squat depth, asking for ankle, hip and groin range the lateral lunge doesn’t demand.

Why can’t I reach full depth on the Cossack squat yet? Limited ankle or hip range is the usual reason, not a lack of leg strength. Building that range separately tends to open up depth faster than repeating the movement alone.

Is it normal for one side to go deeper than the other? Some difference is common, especially early on, since most people carry uneven hip and ankle range between sides. Training both sides regularly and tracking each one’s depth separately helps close that gap over time.

Do I need to reach full depth every rep from the start? No. Working at a shallower, comfortable depth while range builds is a valid way to train this exercise.

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Next in this series: the Pistol Squat, a different unilateral squat pattern that drops straight down instead of shifting sideways.