When sitting, the sitbones (areas marked in red) serve the purpose of supporting the body’s weight, hence they can endure a high load and pressure. They should also be utilised in this way when riding a bike.
In a dynamic riding position the contact point moves from the tip of the sitbones, forwards along the pubic arch to the pubic bone and the central perineal area is used for resting on for both genders. Women however, typically have a lower pubic arch which can result in higher pressure from the saddle nose when riding in a dynamic riding position. The surface area the riders weight is resting on is especially critical in a very dynamic and forward riding position and in such a case the riders weight should not only be supported in the centre but also on the pubic bone.
The sitbone and pubic bones both come together from their widest points in a “V” shape. This means the more dynamic the riding position, the narrower the saddle is allowed to, and should be.
Already in 2002 we developed a simple equation which uses the distance of the sitbone tips in dependence of the riding positing to calculate the perfect saddle width. This method has meanwhile been established globally. The method may be interpreted slightly differently from different saddle manufacturers and many leave the adjustment equation away all together, but our basic concept is used in all of these measuring methods.
The flexibility of the spine has much less influence on the positioning of the pelvis as often assumed. Spine and pelvis should remain in a natural position relative to each other and not be forced into a certain position, even if the body is very flexible.
Especially with the SQlab step saddle it is no longer necessary to tilt the pelvis backwards as the typical pressure zone of the perineal area and pelvis arch no longer pose a problem due to the lowered position of the saddle nose.
The energy which is often reguired to hold the pelvis upright while the upper body taks a dynamic and forward position is no longer required with the SQlab step saddle and can instead be used for pedalling and propelling the bike forward.
In addition, there is substantially less load on the spinal discs.