WindBalanced over midfoot
Side view
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Wrist roller

Arms straight out in front holding a roller bar; the wrists alternately flex and extend to wind a hanging weight up on its rope. The model adds a wrist joint here.

0°Ankle dorsiflexion
2°Knee flexion
5°Hip flexion
0°Trunk from vertical
90°Arm to trunk
8°Elbow flexion
32Ankle spacing, cm
51Hand spacing, cm
-4Knee outside ankle, cm
–Knee cave, ° inside toe line
50 / 50Load left / right, %
0Pelvis drop, cm

Load and joint demand

Load in the model: 5 kg. Balance and joint demand re-solve as you change it.

Lower back
58 / 58
Hip extensors
29 / 29
Knee flexors
27 / 27
Calves
30 / 30
Shoulder, per side
28 / 28
Elbow, per side
11 / 11

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

Forearms and grip
100 pts
Shoulders
41 pts

Effort and your quota

1.5/10 effort1.6fatigue per set

Your quota per set: 10 reps at 5 kg, stopping 2 reps short of failure.

One hard set earns 41 push points, 50 arms points.

Prime movers

Forearm flexors and extensors, anterior deltoid (holding).

What to look for

  • Arms stay at shoulder height; that is half the challenge.
  • Wind up one way, lower slowly the other.
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.