Curl up
Side view
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Wrist curl

Seated with the forearms along the thighs, palms up, hands over the knees. The wrist flexes and extends about 40° each way; the model adds a wrist joint for this one.

-10°Ankle dorsiflexion
75°Knee flexion
120°Hip flexion
38°Trunk from vertical
20°Arm to trunk
94°Elbow flexion
36Ankle spacing, cm
37Hand spacing, cm
5Knee outside ankle, cm
–Knee cave, ° inside toe line
–Load left / right, %
0Pelvis drop, cm

Load and joint demand

Load in the model: 30 kg. Balance and joint demand re-solve as you change it.

Shoulder, per side
31 / 34
Elbow, per side
48 / 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

Forearms and grip
100 pts

Effort and your quota

1/10 effort1fatigue per set

Your quota per set: 10 reps at 30 kg, stopping 2 reps short of failure.

One hard set earns 50 arms points.

Prime movers

Wrist flexors, forearm.

What to look for

  • Forearms stay flat on the thighs.
  • Let the bar roll to the fingers at the bottom if you want more range.
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.