Dip
Side view
Drag to orbit, pinch or scroll to zoom

Star jump

A dip and an explosive jump with the arms and legs flung wide into an X at the top, then back together to land softly. Higher and wider than a jumping jack. Momentum is ignored, so no balance check.

3°Ankle dorsiflexion
2°Knee flexion
3°Hip flexion
3°Trunk from vertical
13°Arm to trunk
10°Elbow flexion
24Ankle spacing, cm
56Hand spacing, cm
-2Knee outside ankle, cm
–Knee cave, ° inside toe line
–Load left / right, %
0Pelvis drop, cm

Load and joint demand

Bodyweight exercise: the load slider has no effect here; body mass comes from your limits.

Shoulder, per side
3 / 12

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

Quads
100 pts
Glutes
82 pts
Calves and shins
64 pts
Shoulders
35 pts

Effort and your quota

7/10 effort7fatigue per set

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

One hard set earns 227 legs points, 35 push points.

Prime movers

Quadriceps, gluteus maximus, calves, hip abductors, deltoids.

What to look for

  • Dip, then explode up and spread into an X.
  • Bring the feet back together before you land.
  • Land softly on the balls of the feet.
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.