4 reps each side · beginner
Sitting with both knees bent and folded to the left (a Z-sit: the right shin across the front, the left shin folded back beside the hip), the left hand resting on the shins and the right fingertips on the mat. The right hand slides out along the mat as the spine bends to the right, while the left arm sweeps up past the ear and over toward the right: a long stretch down the left side. Then back up to sitting tall. The other side next, legs folded the other way.
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.
4 slow, controlled reps on each side. 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: 7 pull points, 21 core points.
Obliques (stretched), quadratus lumborum (stretched), latissimus dorsi (stretched), intercostals, 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.