Jump and catchCentre of mass inside base of support
Side view
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Muscle clean

A 40 kg bar from the hips straight to the front rack with no dip under it: a short hinge and extension start the bar, then the arms pull it high and the elbows turn round under it while the legs stay straight. Teaches the turnover of the clean.

3°Ankle dorsiflexion
2°Knee flexion
5°Hip flexion
1°Trunk from vertical
9°Arm to trunk
2°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: 40 kg. Balance and joint demand re-solve as you change it.

Lower back
12 / 141
Hip extensors
7 / 84
Knee flexors
17 / 19
Calves
36 / 36
Shoulder, per side
19 / 31
Elbow, per side
8 / 52

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

Upper back
100 pts
Shoulders
82 pts
Glutes
46 pts
Biceps
35 pts
Quads
35 pts

Effort and your quota

5.5/10 effort5.7fatigue per set

Your quota per set: 10 reps at 40 kg, stopping 2 reps short of failure.

One hard set earns 81 legs points, 82 push points, 121 pull points, 35 arms points.

Prime movers

Trapezius, deltoids, upper back, gluteus maximus, biceps, quadriceps.

What to look for

  • Legs stay straight once the bar passes the hips.
  • Elbows high and out, then round under the bar.
  • Light bar; speed and path matter.
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.