FORWARD TILT

In some cases individuals may tend to sit on the front edge of the chair. Typically, this is associated with certain task requirements and/or an individual’s adopted sitting habit. Often referred to as “perching” this is a posture that may increase ergonomic risks due to reduced support from the seat back and seat pan. However, the ergonomics of the posture can be enhanced through proper seat pan adjustment. A forward tilt of the seat pan can support this seating style while promoting a healthy spinal posture. By tilting the seat and back forward it provides an alternative sitting posture and relieves lower back pressure.

Seat Recline
Movement is healthy.Reclining our chair only 20° degrees (from 90° to 110°) reduces the stress on our spinal discs by approximately 40% by stimulating he blood flow and relieving the pressure on our spine.

There are different types of seat recline mechanisms and some provide advantages over others. The preferred designs incorporate multiple pivot points integrating the movement of the seat pan and the seat back movement, provide adjustable recline effort as well as lockable settings.

Tension control is important so that a chair can be adjusted to accommodate users of different body types and sizes and for different work styles. A summary of recline mechanism performance for a task chair are as follows:

Performance of Seat Recline Mechanisms in Task Chairs
Minimum Single-Point Pivot — The seat back reclines approximately 20° in relation to the seat pan. With this type of mechanism, the front edge of the seat pan often rises creating unwanted pressure under the thighs.

Better Synchronous Tilt — The motion of the seat back is linked with partial motion of the seat pan to maintain proper lower body and lumbar support throughout the recline motion. For every 2° of seat back recline the rear edge of the seat pan lowers 1°. This minimizes the front edge seat rise and also opens the chest cavity to allow for easier breathing.

Best 3-Point Pivot — This synchronous style mechanism has all the benefits of a synchronous tilt plus it allows the user to further “fine-tune” the control to find a more comfortable posture. It also allows a deeper recline of the seat back to further reduce back stress while maintaining effective lumbar and thigh support.

Minimum Better Best
Single-Point Pivot Synchronous Tilt 3-Point Pivot