Dip, drive, drop underBalanced over midfoot
Side view
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Kettlebell jerk

Take care: Needs a full overhead lockout and good timing; learn the push press first.

One 20 kg bell in the right-hand rack: dip and drive, then drop under the bell with a second dip so the arm locks out while the legs are still bent, and stand up under it.

1°Ankle dorsiflexion
2°Knee flexion
9°Hip flexion
1°Trunk from vertical
26°Arm to trunk
146°Elbow flexion
36Ankle spacing, cm
70Hand spacing, cm
-6Knee outside ankle, cm
–Knee cave, ° inside toe line
50 / 50Load left / right, %
-1Pelvis drop, cm

Load and joint demand

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

Lower back
49 / 49
Hip extensors
25 / 25
Knee flexors
27 / 27
Calves
35 / 35

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
82 pts
Shoulders
64 pts
Triceps
46 pts
Calves and shins
35 pts
Abs and core
35 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 207 legs points, 110 push points, 46 arms points, 35 core points.

Prime movers

Quadriceps, gluteus maximus, deltoids, triceps, calves, abdominals.

What to look for

  • Dip, drive, then dip again under the bell.
  • The arm locks before the legs straighten.
  • Stand up and pause to show the lockout.
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.