hold 30 s · intermediate · move in slowly, hold, come out the same way
Take care: Keep the lift low if the lower back complains; skip it during pregnancy.
Swimming with a resistance band: lying face down with the arms long past the head, hands wide, pulling a band apart. The head, chest, arms and legs lift a little off the mat; the arms hold the band taut while the legs flutter up and down in small quick beats.
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: intermediate. One round counts like light conditioning work: 51 legs points, 16 pull points, 41 core points.
Spinal erectors, gluteus maximus, hamstrings, posterior deltoid, rhomboids and lower trapezius (pulling the band apart), 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.