Descent, eccentricCentre of mass inside base of support
Side view
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Front-rack split squat

Split squat with 50 kg held in the front rack. The load in front keeps the trunk upright and adds work for the upper back.

-25°Ankle dorsiflexion
5°Knee flexion
34°Hip flexion
3°Trunk from vertical
93°Arm to trunk
164°Elbow flexion
21Ankle spacing, cm
56Hand spacing, cm
-1Knee outside ankle, cm
–Knee cave, ° inside toe line
49 / 51Load left / right, %
0Pelvis drop, cm

Load and joint demand

Load in the model: 50 kg. Balance and joint demand re-solve as you change it.

Lower back
70 / 70
Hip extensors
37 / 37
Knee extensors
7 / 95
Calves
42 / 44
Shoulder, per side
36 / 36
Elbow, per side
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

Quads
100 pts
Glutes
100 pts
Abs and core
64 pts
Upper back
41 pts

Effort and your quota

8.5/10 effort8.9fatigue per set

Your quota per set: 10 reps at 50 kg, stopping 2 reps short of failure.

One hard set earns 200 legs points, 41 pull points, 64 core points.

Prime movers

Quadriceps and gluteus maximus of the front leg, upper back (holding the rack), abdominals.

What to look for

  • Elbows stay high so the bar rests on the shoulders.
  • Drop straight down; trunk stays tall.
  • Front heel stays planted.
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.