Lower to floorBalanced over midfoot
Side view
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Dumbbell snatch

A 20 kg dumbbell taken from between the feet to locked out overhead in one movement, one arm. Shown quasi-statically; the real lift is explosive.

1°Ankle dorsiflexion
2°Knee flexion
9°Hip flexion
3°Trunk from vertical
175°Arm to trunk
4°Elbow flexion
44Ankle spacing, cm
55Hand spacing, cm
-7Knee outside ankle, cm
–Knee cave, ° inside toe line
45 / 55Load 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.

Lower back
26 / 228
Hip extensors
15 / 137
Knee extensors
21 / 35
Calves
35 / 35
Shoulder, per side
15 / 142
Elbow, per side
9 / 69

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

Glutes
100 pts
Hamstrings
82 pts
Upper back
64 pts
Shoulders
46 pts

Effort and your quota

6.5/10 effort6.8fatigue per set

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

One hard set earns 182 legs points, 46 push points, 64 pull points.

Prime movers

Gluteus maximus, hamstrings, trapezius, deltoids.

What to look for

  • The hips do the lifting; the arm guides the bell.
  • Punch the arm straight at the top.
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.