Curl, concentric
Side view
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Incline dumbbell curl

Reclined on a bench at 55° so the arms hang behind the trunk line, stretching the long head of biceps before each curl.

-16°Ankle dorsiflexion
68°Knee flexion
51°Hip flexion
35°Trunk from vertical
36°Arm to trunk
10°Elbow flexion
48Ankle spacing, cm
56Hand spacing, cm
3Knee outside ankle, cm
–Knee cave, ° inside toe line
–Load left / right, %
0Pelvis drop, cm

Load and joint demand

Load in the model: 10 kg each hand. Balance and joint demand re-solve as you change it.

Shoulder, per side
12 / 37
Elbow, per side
8 / 36

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

Biceps
100 pts

Effort and your quota

1/10 effort1fatigue per set

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

One hard set earns 60 pull points, 100 arms points.

Prime movers

Biceps brachii (long head emphasised), brachialis.

What to look for

  • Arms hang straight down, behind the body.
  • Keep the elbows back as you curl.
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.