4 reps each side · intermediate
Take care: Turn the fingers out to the sides if the wrists complain, keep the hips lower with a shoulder problem, and skip it with a shoulder injury.
The classical leg pull back: a reverse plank, facing up, hands on the mat under the shoulders with the fingers toward the feet, the body lifted in one straight line from the shoulders to the heels, toes pointed. One straight leg kicks up toward the ceiling to about 65° and lowers again without the hips dropping; then the other leg.
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: intermediate. One round counts like light conditioning work: 64 legs points, 23 push points, 22 pull points, 16 arms points, 12 core points.
Gluteus maximus, hamstrings, posterior deltoid, triceps, rhomboids, rectus abdominis and transversus abdominis (holding the hips up), hip flexors (kicking); pectoralis major and anterior deltoid 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.