hold 30 s · beginner · move in slowly, hold, come out the same way
Take care: Keep the lift low, or swim with the arms only, if the lower back complains; skip it during pregnancy.
Lying face down with the arms long past the head and the legs long, the head, chest, arms and legs all lift a little off the mat, then the right arm and left leg and the left arm and right leg flutter up and down in small quick beats, like swimming in place, for a count of five breathing in and five breathing out.
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.
Hold for 30 seconds: move into the pose slowly, breathe steadily, and come out the way you went in. 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: 51 legs points, 16 pull points, 41 core points.
Spinal erectors, gluteus maximus, hamstrings, posterior deltoid, lower trapezius and rhomboids, transversus abdominis (holding the belly lifted).
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.