SlamBalanced over midfoot
Side view
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Medicine ball slam

An 8 kg ball held overhead on tiptoe is driven down to the floor in front of the feet with a hip hinge and squat. Momentum is ignored.

-13°Ankle dorsiflexion
2°Knee flexion
13°Hip flexion
10°Trunk from vertical
171°Arm to trunk
33°Elbow flexion
46Ankle spacing, cm
24Hand spacing, cm
-7Knee outside ankle, cm
–Knee cave, ° inside toe line
50 / 50Load left / right, %
0Pelvis drop, cm

Load and joint demand

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

Lower back
41 / 173
Hip extensors
25 / 106
Knee extensors
30 / 43
Calves
42 / 49
Shoulder, per side
5 / 25
Elbow, per side
6 / 27

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

Lats
100 pts
Abs and core
82 pts
Glutes
64 pts
Triceps
46 pts

Effort and your quota

5.5/10 effort5.7fatigue per set

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

One hard set earns 64 legs points, 46 push points, 100 pull points, 46 arms points, 82 core points.

Prime movers

Latissimus dorsi, abdominals, gluteus maximus, triceps.

What to look for

  • Reach tall first, then throw the whole body into it.
  • Catch low with a flat back.
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.