A rotatable seat cradle including a lumbar supporting back, a thigh supporting front, an intermediate pelvic support bucket located between the back and the front, and an upwardly sloping transition wall that extends continuously and co-extensively between the pelvic support bucket and the thigh supporting front. The seat cradle is pivotally coupled to a stand or to a yoke connected to a chair base. The thigh supporting front of the seat cradle lies above the pelvic support bucket and cantilevers outwardly from the upwardly sloping transition wall. A seated user shifting his weight towards the front of the seat cradle pushes his legs against the thigh supporting front to generate a rotational force thereagainst for causing a corresponding rotation of the seat cradle relative to the stand or the yoke to which the seat cradle is pivotally coupled.