Descent, eccentricBalanced over midfoot, bar 0.1 cm behind
Side view
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Box squat

Wide stance, sitting back to a box at parallel: shins more upright than a back squat and the hips further back, with the chest still up (trunk within 55°). The box height is taken from the solved bottom position.

0°Ankle dorsiflexion
2°Knee flexion
12°Hip flexion
5°Trunk from vertical
35°Arm to trunk
138°Elbow flexion
52Ankle spacing, cm
84Hand spacing, cm
-8Knee 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
10 / 451
Hip extensors
10 / 266
Knee extensors
29 / 65
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
Hamstrings
82 pts
Adductors
64 pts
Quads
46 pts

Effort and your quota

8.5/10 effort8.9fatigue per set

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

One hard set earns 292 legs points.

Prime movers

Gluteus maximus, hamstrings, adductors, quadriceps.

What to look for

  • Shins stay more upright than in a back squat; the hips travel back, the chest stays up.
  • Sit on the box briefly without relaxing, then drive up.
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.