The Cossack Squat: Side-to-Side Strength and Hip Mobility in One
The Cossack squat is a wide-stance squat where you shift your weight over to one side, bending that knee deeply while the other leg stays straight with its toes pointing up, then push back to the middle and repeat on the other side. It strengthens the legs through a sideways movement that most gym programmes ignore, and it stretches the inner thighs and hips under control at the same time. Few people can reach full depth at first, and they do not need to. Start with a shallow shift, use support if you need it, and add depth over weeks rather than forcing it in one session.
Why train side to side at all
Most strength training happens front to back. Squats, deadlifts, lunges and presses all move in roughly the same plane. Life and sport do not. Stepping sideways off a kerb, changing direction on a five-a-side pitch, getting low to pick something up from an awkward angle: all of these load the hips and inner thighs in ways a normal squat does not.
The Cossack squat covers that gap in three ways:
- It loads one leg at a time in a deep position, building strength in the glutes and quadriceps of the bent leg.
- It stretches the adductors (inner-thigh muscles) of the straight leg under control, which many desk-bound adults find tight.
- It asks a lot of the ankle and hip of the bent leg, so it doubles as an active mobility drill.
If stiff hips are your main issue, our guide to hip mobility exercises pairs well with it.
How to do a Cossack squat
- Take a wide stance. Feet roughly twice shoulder width, toes turned out slightly.
- Shift to one side. Push your hips back and over towards the right foot, bending the right knee. Keep the right heel on the floor.
- Let the left leg straighten. As you go lower, roll onto the left heel so the toes point up. This is what lets the straight leg move freely.
- Keep the chest up and the bent knee tracking over the toes. Arms forward help you counterbalance.
- Go only as low as you control. Stop before your heel lifts or your back rounds.
- Push back to the middle through the bent leg, then shift to the other side.
Alternate sides each rep, or do all reps on one side first. Alternating is better for learning; same-side sets are harder. Breathe out as you push back to the middle, and keep the movement slow enough that you could stop at any point. If one side reaches noticeably less depth than the other, that is normal at first; work both sides to the depth of the tighter one and let the difference close over time.
A progression that builds depth safely
| Stage | What to do | Move on when |
|---|---|---|
| 1. Lateral shift | Wide stance, shift side to side with a shallow knee bend, both feet flat | It feels smooth for 10 reps a side |
| 2. Supported Cossack | Hold a rack upright or sturdy post in front and go a little deeper | You reach a comfortable depth without pulling hard on the support |
| 3. Counterbalanced | Hold a light dumbbell or plate out in front at chest height | You can pause at the bottom for two seconds |
| 4. Goblet Cossack | Dumbbell held at the chest, as in a goblet squat | Add weight slowly |
Counterintuitively, holding a light weight in front often makes the exercise easier at first, because it lets you sit back without falling.
Common faults and fixes
The heel lifts
If the heel of the bent leg comes off the floor, you have reached the limit of your ankle mobility. Stop a little higher, or briefly place a small plate under the heel while you work on ankle range.
The chest collapses
Folding forward to get lower means the hip is not yet ready for that depth. Use a counterweight and accept a shallower squat.
The straight-leg foot stays flat
Keeping the straight leg’s foot flat twists the knee. Let it roll onto the heel with toes pointing up.
The bent knee caves in
Push the knee out over the little toes. If it keeps caving, reduce depth.
Bouncing at the bottom
It is tempting to bounce into the stretch. Control the descent and pause instead.
How to use it in a week
There are two useful roles.
- Warm-up and mobility. Two sets of five to eight slow reps a side before squats or deadlifts, unloaded or with a light counterweight.
- Accessory strength. Two or three sets of six to eight reps a side with a goblet hold, after your main lower-body work, once or twice a week.
It sits well alongside other single-leg exercises. Our comparison of split squats and lunges covers the front-to-back options.
If you have a groin, knee or hip injury, a heart condition, are pregnant or are returning after a long break, check with your GP first. A gentle stretch sensation in the inner thigh is normal; sharp pain in the groin or knee is not, and is a reason to stop. The NHS physical activity guidance is a useful baseline for how much strength work adults should be doing each week.
Coaching it in the studio
The Cossack squat is a good example of an exercise that looks simple and is hard to self-coach. From the front, I watch whether the bent knee stays over the foot; from the side, whether the hips go back or the chest drops. Most people progress from stage one to a supported deep position within a few weeks of practice. In a private personal training session in Highgate, the studio is booked to you alone, so there is no awkwardness about practising a deep side squat in front of strangers. Current plans and prices are on our personal trainer page.
Questions we get asked
What muscles does the Cossack squat work?
Mainly the glutes and quadriceps of the bent leg and the adductors of both legs, with the trunk working to keep you upright.
Why can I not get low?
Usually a combination of ankle mobility, hip mobility and inner-thigh tightness. It improves with regular practice at a depth you control.
Is it a stretch or a strength exercise?
Both. Unloaded and slow, it works as mobility; loaded, it is a strength exercise.
Can older adults do it?
Many can, starting with the lateral shift and supported version. Balance and hip strength are worth training at any age.
Book with The Highgate House
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