hold 60 s · intermediate · move in slowly, hold, come out the same way
Take care: Keep the head down or the legs higher if the neck or lower back strains; skip it during pregnancy and after giving birth until the abdominals have recovered.
The Hundred with a pilates ring held between the ankles: from lying with the straight legs up and the ring between the ankles, the head and shoulders curl up about 30°, the legs lower to about 45° gently squeezing the ring, and the straight arms hover above the mat reaching toward the feet. Held while the arms pump, five counts in and five counts out, ten times.
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 60 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: 22 legs points, 25 push points, 12 arms points, 29 core points.
Rectus abdominis (holding), transversus abdominis, adductors (squeezing the ring), obliques, hip flexors (holding the legs), deltoids, triceps.
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.