Many owners of ergonomic kneeling chairs complain about pain issues in their shins. Ergonomic kneeling chairs are designed such that the seat slopes down and part of the body's weight is supported by a shin rest. The body becomes accustomed to sitting a certain way, and this way has been reinforced, for most of us, our entire lives. Once asked to move to a new way of sitting, the body will naturally feel discomfort because the pattern is broken, as is the case with shin pain. A quick fix for any discomfort in the shins: adjust the chair.
An ergonomic kneeling chair has two main adjustments that are available in most designs. First, the forward sloping angle of the seat has a direct effect on the weight distribution between the shins and buttocks. A traditional chair has a flat angle, 90 degrees, of which 90% of the body's weight is supported by the seat and the other 10% remains in the contact between the feet and the ground. The seat slopes down 20-30%. In this configuration, up to 20% of the body's weight is supported by the shins in this configuration.
Most modern ergonomic kneeling chairs have an adjustment for the slope of the seat. If you're purchasing an ergonomic kneeling chair, it is recommended to invest in a model that has this adjustment available. Older models might have a height adjustment which also affects the seat slope since the design incorporates a folding action. Newer models have an independent adjustment which doesn't affect the height of the chair. Preserving the height of the chair may or may not be important to your ergonomic station, depending on the placement, or height, or your monitor.
The second adjustment that will affect shin comfort is the shin rest itself. In more expensive models of ergonomic kneeling chairs, an angled adjustment is available for the shin rest. When adjusting, a sharper angle will affect how much compression is felt between the calves and the thighs. Many report that this contact is uncomfortable due to lack of circulation in the legs, so they relax the angle. Otherwise, a sharper angle tends to be more beneficial for the bones of the body. The compression in a sharp angle strengthens the bone density of the femur and fibula, promoting stability and robustness. A sharp angled seat, is a the posture that most mimics the kneeling of Buddhist monks, of which the original design was modeled.
To add, it is possible that the padding of the shin rest is inadequate. Be sure to select an ergonomic kneeling chair with a high quality firm foam material on the padding. Many consumers complain about cheap kneeling chairs that do not have adequate padding on the shins and they can actually feel the wood contact. Memory foam and thick cotton padding are typically the best options. When purchasing, be sure to browse the reviews that people leave. If the shin padding is bad, this will be one of the first things customers complain about in their ergonomic kneeling chair.