Turn and throw
Side view
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Medicine ball rotational throw

Standing side-on to a wall with a 4 kg medicine ball: the ball is loaded back by the far hip as the hips and shoulders turn away, then the hips drive round and the ball is thrown hard into the wall at chest height. Done on each side.

10°Ankle dorsiflexion
22°Knee flexion
20°Hip flexion
6°Trunk from vertical
18°Arm to trunk
64°Elbow flexion
44Ankle spacing, cm
10Hand spacing, cm
-6Knee 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
19 / 19

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

Abs and core
100 pts
Glutes
82 pts
Shoulders
64 pts
Chest
46 pts

Effort and your quota

5.5/10 effort5.5fatigue per set

Your quota per set: 8 reps at bodyweight, stopping 2 reps short of failure.

One hard set earns 82 legs points, 110 push points, 100 core points.

Prime movers

Obliques, gluteus maximus, deltoids, pectoralis major, rectus abdominis.

What to look for

  • Load the ball back by the hip, eyes on the wall.
  • Turn the hips first, then the shoulders, then the arms.
  • Follow through to the wall; let the back knee turn in.
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.