6 reps · beginner
Sitting tall with the straight legs a little wider than the hips, feet flexed, and the arms reaching forward at shoulder height, the head drops and the spine rounds forward one vertebra at a time, as if over a ball, the arms reaching on past the feet; then it rolls back up to sitting tall. The spine rounds into a C, the upper back most, as the trunk tips about 40° forward.
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: beginner. One round counts like light conditioning work: 11 legs points, 39 core points.
Spinal erectors and hamstrings (stretched), rectus abdominis, transversus abdominis.
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.