Dip, drive, drop underBalanced over midfoot
Side view
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Double kettlebell jerk

Take care: An advanced lift: master the single jerk and the double push press first.

Two 20 kg bells in the rack: dip and drive, drop under with a second dip to lock both arms out, then stand up under them.

0°Ankle dorsiflexion
2°Knee flexion
7°Hip flexion
0°Trunk from vertical
25°Arm to trunk
146°Elbow flexion
38Ankle spacing, cm
20Hand spacing, cm
-5Knee outside ankle, cm
–Knee cave, ° inside toe line
50 / 50Load left / right, %
0Pelvis drop, cm

Load and joint demand

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

Lower back
78 / 78
Hip extensors
39 / 39
Knee flexors
37 / 37
Calves
43 / 60
Shoulder, per side
42 / 42
Elbow, per side
35 / 57

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
Upper back
35 pts

Effort and your quota

8/10 effort8.3fatigue per set

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

One hard set earns 207 legs points, 110 push points, 35 pull points, 46 arms points.

Prime movers

Quadriceps, gluteus maximus, deltoids, triceps, calves, upper back.

What to look for

  • Dip, drive, dip again.
  • Arms lock before the legs straighten.
  • Elbows back on the ribs to catch the bells.
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.