Arm weights: the bug
8 reps · beginner
Take care: Keep the forward lean small, or stand upright, with a lower-back problem.
From the classical standing arm series: standing in pilates stance with the knees soft and the body tipped forward about 35° from the hips on a long, flat back, the arms rounded in front of the chest as if hugging a tree. The arms open out wide to the sides at shoulder height, the shoulder blades drawing together like a beetle opening its wings, then close again in front. Done here without the light hand weights.
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. 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: 27 legs points, 35 pull points, 23 core points.
Posterior deltoid, rhomboids and middle trapezius (opening the arms), spinal erectors and gluteus maximus (holding the lean), hamstrings, transversus abdominis.
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.