Parsva Balasana
hold 30 s each side · beginner · move in slowly, hold, come out the same way
Take care: Rest the head on a block if the neck strains, keep the twist small with a shoulder injury, and pad the knees.
Parsva Balasana, from hands and knees: the hips stay over the knees while the right arm slides under the left arm, palm up, along the mat to the left, until the right shoulder and the side of the head rest on the mat. The chest turns about 70° toward the left; the left hand stays planted ahead with its elbow bent.
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 on each side: 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: beginner. One round counts like light conditioning work: 35 pull points, 16 core points.
Rhomboids, posterior deltoid and trapezius of the threaded arm (stretched), thoracic rotators and obliques (stretched), external obliques.
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.