Standing on the right leg with a 20 kg bell in the left hand (the opposite side); the free leg extends behind as the trunk hinges to about 75°. The cross-body load makes the hip resist turning open.
Load in the model: 20 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 20 kg, stopping 2 reps short of failure.
One hard set earns 200 legs points, 23 arms points, 64 core points.
Hamstrings and gluteus maximus of the standing leg, gluteus medius, obliques, grip.
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.