Descent, eccentricBalanced over midfoot, bar 0.8 cm behind
Side view
Drag to orbit, pinch or scroll to zoom

Low-bar back squat

Powerlifting style: 100 kg sitting about 5 cm lower on the back, across the rear shoulders, with a wider grip and a slightly wider stance. Hip and knee follow a depth profile to just below parallel; with the bar lower, the solved trunk leans further forward than in a high-bar squat.

1°Ankle dorsiflexion
2°Knee flexion
11°Hip flexion
8°Trunk from vertical
27°Arm to trunk
131°Elbow flexion
48Ankle spacing, cm
92Hand spacing, cm
-7Knee outside ankle, cm
–Knee cave, ° inside toe line
50 / 50Load left / right, %
0Pelvis drop, cm

Load and joint demand

Load in the model: 100 kg. Balance and joint demand re-solve as you change it.

Lower back
6 / 424
Hip extensors
10 / 255
Knee extensors
29 / 86
Calves
61 / 61

N·m now / peak over the rep.

Faults

Faults grow with knee bend and apply to lifts standing on the floor. The fault check flags a knee caving more than 10° inside the line of the toes and a load split beyond 60/40. Knee cave shows best in the front camera.

Body

Femur changes keep standing height fixed by shortening or lengthening the torso. Longer femurs force more forward lean in any squat.

Muscles worked

Glutes
100 pts
Quads
82 pts
Adductors
64 pts
Hamstrings
46 pts
Lower back
35 pts

Effort and your quota

9.5/10 effort9.9fatigue per set

Your quota per set: 10 reps at 100 kg, stopping 2 reps short of failure.

One hard set earns 292 legs points, 35 core points.

Prime movers

Gluteus maximus, quadriceps, adductor magnus, hamstrings, spinal erectors.

What to look for

  • Bar sits across the rear shoulders, below the bony knob at the base of the neck.
  • Sit the hips back; the chest leans further forward than a high-bar squat.
  • Keep the wrists straight; the hands only pin the bar in place.
How the model works, and its limits

One 3D skeleton drives both views. Segment lengths and widths are Winter's anthropometric ratios of height; segment masses and centre-of-mass positions follow Dempster's data. For free-standing lifts the whole-body angle is found numerically so the combined centre of mass of lifter and load sits over the middle of the foot. Arms and legs use two-link inverse kinematics with a pole direction. Rep timing follows a minimum-jerk profile.

Balance is quasi-static, so ballistic lifts are shown slowed down. Cable pull and pad support forces are not modelled. The spine is one rigid segment and joints have no range-of-motion limits or muscle forces.