Take care: Keep the back flat as you lift; skip it with a sore lower back.
A 30 kg sandbag on the floor in front of the feet: hinge down and grab it, then drive the hips through to roll it up the thighs into a bear hug at the chest, and stand tall. Lowered back to the floor between reps.
Load in the model: 30 kg. Balance and joint demand re-solve as you change it.
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.
Femur changes keep standing height fixed by shortening or lengthening the torso. Longer femurs force more forward lean in any squat.
Your quota per set: 10 reps at 30 kg, stopping 2 reps short of failure.
One hard set earns 228 legs points, 45 pull points, 17 arms points, 64 core points.
Gluteus maximus, hamstrings, spinal erectors, quadriceps, upper back, biceps (holding).
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.