Supta Virasana
hold 60 s · intermediate · move in slowly, hold, come out the same way
Take care: Stay sitting up in hero, or on a block, if the knees hurt; skip it with a knee injury and ease off if the lower back pinches.
Supta Virasana supported on blocks: sitting between the heels in hero (knees together, the shins along the outsides of the hips, the tops of the feet down), the trunk lowers back onto two blocks, a low one under the shoulder blades and a tall one under the head, about 17° up from the mat. The knees stay down on the mat and the arms rest out to the sides.
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. Yoga 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: 15 legs points, 9 core points.
Quadriceps (stretched), hip flexors (stretched), tibialis anterior (stretched), abdominals (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.