The stools created by us base on the natural work of the spine and impose the appearance of its natural curvatures i.e. lumbar and cervical lordosis, as well as thoracic and sacral kyphosis. It is possible to achieve thanks to the anteversion of the pelvis of approximately 12 degrees, when the front edge of the seat slightly heads downwards, the angle between the trunk and thigh stands at about 120 degrees, whereas the angle of the hip joint abduction is of approximately 30 degrees. Such situation guarantees the healthiest state of the lumbar lordosis. Then, side bends and leaning out on our seat is performed with movement amortisation. It is paramount when we take into account that no instability is felt, instead of which relief of strain in the pelvis, back and abdominal muscles appears. Muscle tone is correct, which significantly improves body mobility.