The barbell back rack cossack squat is a wide-stance lateral squat performed with a barbell on the upper back, sinking onto one leg while the other stays straight to load the quads and hips. It is the loaded progression of thegoblet cossack squat: the bar sits high behind the neck instead of counterbalancing at the chest, so the torso must stay upright with nothing out front to lean against, and any tilt of the bar is felt at the bottom. Lifters with a clean goblet cossack program it as a heavy lower body accessory after their main squat.
What Muscles Does the Barbell Back Rack Cossack Squat Work?
- Primary: Quadriceps of the bent leg
- Secondary: Gluteus maximus, gluteus medius, adductors of the straight leg
- Tertiary: Hamstrings, erector spinae, obliques, upper trapezius
How Do You Set Up for the Barbell Back Rack Cossack Squat?
Set the bar in a squat rack just below shoulder height. Step under it so it rests across the upper traps, grip it slightly wider than shoulder width, and pull the elbows down and back. Stand to unrack, step back twice, and widen the feet to about one and a half shoulder widths with the toes pointing forward or slightly out. Brace the trunk, lift the chest, and centre the weight over both feet.
How Do You Perform the Barbell Back Rack Cossack Squat?
- Shift your weight onto one leg and bend that knee, keeping the other leg straight with the foot flat.
- Sit sideways and down over the bent leg, tracking the knee over the toes and letting the straight foot roll onto its heel with the toes lifting.
- Reach the bottom when the working hip is below the knee with the bar still level across the shoulders.
- Pause for one count, chest tall and the straight leg fully extended.
- Drive through the whole foot of the bent leg to stand back up into the wide stance.
- Re-centre the bar over both feet, then shift to the other side for the next rep.
What Are the Key Form Cues?
- Bar stays level: keep both ends of the bar at the same height through the descent, so the trunk sinks straight down rather than tipping toward the working leg.
- Elbows pull the bar into the back: drag the elbows down and back the whole rep, so the bar cannot roll up the neck at the bottom.
- Let the straight leg's toes rotate up to the ceiling as you descend.
- Push the working knee out over the pinky toe on the way down.
- Sit down slowly and stand up hard.
What Are the Most Common Mistakes?
- Loading the bar like a back squat: the descent stops halfway and the torso pitches forward, so choose a load you can take to full depth on your weaker side.
- Letting the working heel lift: the weight shifts to the toes and the knee drives forward under the bar, so widen the stance until the heel stays down.
- Bending the straight leg: the adductor stretch is lost and the rep becomes a shallow side lunge, so lock that knee and lift the toes.
- Tilting the bar toward the working side: the spine side-bends under load at the bottom and the straight-leg hip takes the shear, so keep the bar level and the ribs stacked.
- Bouncing out of the bottom: the working knee collapses inward under the rebound, so pause for one count before standing.
What Are the Best Barbell Back Rack Cossack Squat Variations?
- Goblet cossack squat: a kettlebell at the chest counterbalances the hips, the step before loading the back.
- Paused back rack cossack squat: a two-count hold at the bottom for depth and control.
- Front rack cossack squat: the bar on the front of the shoulders keeps the torso more upright and loads the quads harder.
- Goblet Low Switch Cossack Squat: shifting side to side while staying low, for time under tension.
- Dumbbell back rack cossack squat: two dumbbells resting on the shoulders replace the bar in a gym without a rack.
How Do You Progress the Barbell Back Rack Cossack Squat?
- Add 5 pounds to the bar once every set reaches 8 clean reps per side at full depth.
- Work from 5 reps per side up to 8 before going heavier.
- Start at 2 sets per side and add a third once both sides reach the same depth.
- Add a 2-second pause at the bottom, or a 3-second descent, before the next weight increase.
How Should You Program the Barbell Back Rack Cossack Squat?
Program the barbell back rack cossack squat as a heavy lower body accessory after your main squat, once a week, or lighter as a loaded warm-up before it. Do 2 to 3 sets of 5 to 8 reps per side with 90 to 120 seconds of rest between sets. Pair it with a single leg Romanian deadlift so the hamstrings match the quad work on each leg.