6 reps · advanced
Take care: An advanced roll: master rolling like a ball and the seal first; skip it with a neck, back or knee injury, osteoporosis, and during pregnancy.
The classical crab, rolling part: sitting balanced just behind the sit bones in a tight ball with the shins crossed, the knees open toward the shoulders and the hands holding the feet, the body rolls back onto the shoulder blades and up again to the balance without losing its shape. Classically the legs switch their cross at the top and the roll carries on forward onto the knees and the crown of the head; that finish is left out here. Modelled as a rigid, rounded body rocking on its back.
Bodyweight: no weights. Joint demand below is your own body's weight in this position.
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.
6 slow, controlled reps. Pilates is practised for control, balance and mobility, never to failure, so this does not change with your limits.
Level: advanced. One round counts like light conditioning work: 39 core points.
Rectus abdominis, transversus abdominis, obliques (holding the shape), hip external rotators; spinal erectors massaged and stretched.
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.