Dip, drive and catchCentre of mass inside base of support
Side view
Drag to orbit, pinch or scroll to zoom

Push jerk

A 60 kg bar starts in the front rack: a short, straight dip of the knees, an explosive drive that sends the bar overhead, and a second dip to catch it locked out, then stand. The trunk stays upright, solved for balance every frame.

3°Ankle dorsiflexion
2°Knee flexion
9°Hip flexion
5°Trunk from vertical
88°Arm to trunk
164°Elbow flexion
30Ankle spacing, cm
56Hand spacing, cm
-3Knee outside ankle, cm
–Knee cave, ° inside toe line
50 / 50Load left / right, %
0Pelvis drop, cm

Load and joint demand

Load in the model: 60 kg. Balance and joint demand re-solve as you change it.

Lower back
22 / 158
Hip extensors
7 / 96
Knee extensors
20 / 26
Calves
42 / 42
Shoulder, per side
41 / 42
Elbow, per side
73 / 78

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

Shoulders
100 pts
Triceps
82 pts
Quads
64 pts
Glutes
46 pts
Upper back
35 pts
Calves and shins
35 pts

Effort and your quota

7.5/10 effort7.8fatigue per set

Your quota per set: 10 reps at 60 kg, stopping 2 reps short of failure.

One hard set earns 135 legs points, 182 push points, 35 pull points, 82 arms points.

Prime movers

Deltoids, triceps, quadriceps, gluteus maximus, upper trapezius, calves.

What to look for

  • Dip straight down; trunk stays vertical.
  • Drive hard with the legs, then punch under.
  • Catch with the arms locked, bar over the back of the neck.
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.