Lower, eccentricBalanced over midfoot, bar 6.7 cm ahead
Side view
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Barbell overhead triceps extension

Standing with a 25 kg EZ bar held overhead, upper arms pointing nearly straight up. The elbows flex from 15° to 135° so the bar lowers behind the head, stretching the long head of the triceps.

3°Ankle dorsiflexion
2°Knee flexion
4°Hip flexion
3°Trunk from vertical
168°Arm to trunk
15°Elbow flexion
28Ankle spacing, cm
43Hand spacing, cm
-3Knee outside ankle, cm
–Knee cave, ° inside toe line
50 / 50Load left / right, %
0Pelvis drop, cm

Load and joint demand

Load in the model: 25 kg. Balance and joint demand re-solve as you change it.

Lower back
37 / 37
Hip extensors
20 / 20
Knee flexors
25 / 25
Calves
38 / 38
Shoulder, per side
12 / 30
Elbow, per side
2 / 44

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 25 kg, stopping 2 reps short of failure.

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

Prime movers

Triceps brachii, long head emphasised by the overhead position.

What to look for

  • Elbows point up, not flared wide.
  • Lower behind the head for a deep stretch.
  • Ribs down; no arching.
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.