Dip
Side view
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Barbell jump squat

A light 20 kg bar on the back: counter-movement dip, extension through the toes and about 20 cm of flight, then the same dip to land. Momentum is not modelled, so there is no balance check.

3°Ankle dorsiflexion
2°Knee flexion
5°Hip flexion
3°Trunk from vertical
37°Arm to trunk
138°Elbow flexion
30Ankle spacing, cm
84Hand spacing, cm
-3Knee outside ankle, cm
–Knee cave, ° inside toe line
–Load left / right, %
0Pelvis drop, cm

Load and joint demand

Load in the model: 20 kg. Balance and joint demand re-solve as you change it.

No gravity-based joint demand to show for this exercise.

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
82 pts
Calves and shins
64 pts
Hamstrings
46 pts

Effort and your quota

7.5/10 effort7.8fatigue per set

Your quota per set: 10 reps at 20 kg, stopping 2 reps short of failure.

One hard set earns 273 legs points.

Prime movers

Quadriceps, gluteus maximus, calves, hamstrings.

What to look for

  • Keep the bar pinned to the back as you jump.
  • Land softly through the same dip.
  • Light load only; speed is the point.
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.