8 reps each side · intermediate
Take care: Keep the elbows wide so the hands never pull the neck; skip it during pregnancy and after giving birth, and with a back injury that twisting aggravates.
The last of the Series of Five: curled up with the hands behind the head, elbows wide. One knee draws in as the other leg reaches long at about 40°, and the trunk rotates toward the bent knee, bringing the opposite elbow and armpit toward it; the legs switch and the trunk turns the other way, staying lifted throughout.
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.
8 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: intermediate. One round counts like light conditioning work: 35 core points.
Obliques (internal and external), rectus abdominis (holding the curl), transversus abdominis, hip flexors.
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.