ExtendBalanced over midfoot
Side view
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Triceps kickback

Hinged to about 60° with the upper arm held along the trunk; the elbow extends from 90° to straight behind the body.

0°Ankle dorsiflexion
22°Knee flexion
82°Hip flexion
60°Trunk from vertical
10°Arm to trunk
90°Elbow flexion
36Ankle spacing, cm
45Hand spacing, cm
-3Knee outside ankle, cm
0°Knee cave, ° inside toe line
50 / 50Load left / right, %
0Pelvis drop, cm

Load and joint demand

Load in the model: 8 kg each hand. Balance and joint demand re-solve as you change it.

Lower back
143 / 143
Hip extensors
95 / 95
Knee flexors
33 / 33
Calves
34 / 34
Shoulder, per side
21 / 59
Elbow, per side
11 / 26

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

Triceps
100 pts

Effort and your quota

1.5/10 effort1.6fatigue per set

Your quota per set: 10 reps at 8 kg each hand, stopping 2 reps short of failure.

One hard set earns 100 push points, 100 arms points.

Prime movers

Triceps brachii.

What to look for

  • Upper arm stays still and parallel to the torso.
  • Squeeze at full extension.
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.