Cossack Squat
The Cossack squat is a side-to-side squat in which you shift your weight onto one leg and sit down deep over it while the other leg stays straight out to the side. It works the quadriceps and glutes of the bent leg and loads the inner-thigh adductors of the straight leg at a long stretch, training a depth and direction that most squats and lunges never reach.
Also called: Side Lunge Squat, Cossack Lunge, Side-to-Side Squat, Russian Cossack Squat · Equipment: bodyweight · Pattern: squat
Step by step
- Stand with your feet about one and a half to two times shoulder-width apart, toes turned out slightly. Clasp your hands in front of your chest, or hold a light weight there.
- Shift your weight onto one leg, pushing your hips back and bending that knee while the other leg straightens out to the side.
- Keep the whole foot of the bent leg flat. On the straight leg, rest on the heel with the toes pointing up if your hips and ankles allow, or keep the foot flat.
- Sit down as deep as you can control, with the bent knee tracking over your middle toes and your chest up.
- Push through the whole foot of the bent leg to rise back to the centre.
- Shift across to the other side, or finish all your reps on one side before switching.
- Match the depth on both sides, going only as deep as you can with a flat heel and a steady knee.
- Sit your hips back over the bent leg
- Bent knee over your middle toes
- Straight leg long, heel on the floor
- Chest up as you sink
- Push the floor away to rise
- Only as deep as you can control
In VALDA, these cues are one tap away on the exercise while you train.
What it trains
| Muscle | Role | Evidence |
|---|---|---|
| Quadriceps: vastus lateralis | Prime mover | C |
| Quadriceps: vastus medialis | Prime mover | C |
| Adductors | Prime mover | C |
| Quadriceps: vastus intermedius | Prime mover | D |
| Gluteus maximus | Prime mover | C |
| Hamstrings: biceps femoris (long head) | Secondary | D |
| Gluteus medius/minimus | Stabiliser | C |
| Soleus | Stabiliser | D |
| Tibialis anterior | Stabiliser | D |
| Erector spinae | Stabiliser | D |
| Adductors | Dynamic stabiliser | D |
Evidence grades: A = strong research base · B = good · C = limited · D = coaching consensus.
What goes wrong, and the fix
Bent knee caving inward
Fix: Push the bent knee out so it tracks over your middle toes all the way.
Heel of the bent leg lifting
Fix: Keep the whole foot flat and sit only as deep as the heel stays planted.
Chest folding forward
Fix: Hold a light weight at your chest as a counterweight and keep your chest up.
Straight leg bending
Fix: Keep the straight leg long, and narrow your stance slightly if the knee bends.
Dropping into the bottom
Fix: Take about two seconds to sink and pause briefly at the bottom.
Uneven depth side to side
Fix: Match your depth on both sides to the side that moves less freely.
What the research says
Muscle growthRehab & prehabGeneral fitnessSport performanceEnduranceFat loss & conditioning
- Range of motion — A systematic review found training through a full range of motion, including the lengthened position, favours leg muscle growth over partial range. There is no direct growth study on the Cossack squat itself.
- Stance width — A squat study found wider stances raised hip-extensor and inner-thigh muscle demand compared with narrow stances, while quadriceps demand stayed similar.
- Single-leg transfer — A meta-analysis found single-leg training carried over more to single-leg jumping, and two-leg training more to two-leg strength.
- Load and reps — A common approach is bodyweight sets of 6–12 reps per side, adding a light weight held at the chest once full depth is controlled. There is no research on the best load for this exercise.
- Placement — Many lifters use it in a leg-day warm-up or as an accessory after the main lift.
Swap it mid-workout
With VALDA Pro, FLEX offers alternatives like these when you swap an exercise mid-workout.
Log the cossack squat in VALDA, with these cues one tap away while you train and your history for it in one place.
General information about exercise technique, not medical advice. If you have an injury or a health condition, your healthcare provider is the right person to ask.