Dynamic sitting occurs in a chair that is fitted with a mechanism that allows the angle between the backrest and seat to change. By continuously changing this angle, you automatically stimulate, or activate various muscles in your lower back, core and legs. As a result, the blood flow through these muscles increases, bringing oxygen and other nutrients to the muscles and carrying away the waste products of muscle metabolism. By doing so, muscle fatigue and its associated pain is reduced, particularly in the lower back, core and legs.
Dynamic Sitting has long been acknowledged as the global benchmark for ergonomic comfort.
Chairs fitted with either a Synchronous (synchro) or a Free-Float mechanism, encourage or aid Dynamic Sitting.
1. Synchro Mechanism
Synchro mechanisms are mechanical swivel & tilt devices that allow the angle of the chair backrest and seat to change in a fixed ratio. A synchro mechanism ensures that the movement of the backrest is always greater than that of the seat.
Most synchro mechanisms have a 2:1 ratio that moves the backrest 2 degrees for every 1 degree of movement in the seat.
Synchro mechanisms promote Dynamic Sitting
The seat and backrest move together in a fixed ratio, where the backrest always moves more than the seat. With a typical 2:1 ratio, the backrest will tilt backwards by 20 for every 10 of seat tilt.
If the mechanism is unlocked, it will be free-floating. In this position, the chair is dynamic and the backrest provides continual back support by moving with you.
In South Africa, synchro mechanisms are fitted on most ergonomic chairs.
2. Free-Float Mechanism and Dynamic Sitting
A Free-Float mechanism allows you to independently, or separately, adjust the seat and backrest of the chair. This enables you to adjust the angles of the seat and backrest to suit your preferred sitting posture.
Like a synchro mechanism, if the Free-Float mechanism is unlocked, the chair is dynamic and the backrest provides continual back support as it moves with you.