My response was based on that you might be trying to define a stereotype of older riders. Calculating the average height of American males to be for example 5'10" does not imply that all American males are 5'10". All trousers must be fit to the man. There may be some value for fitters to understand the trends of aging, but each person's fit and the issues that must be considered is an individual portrait. I and several other senior citizen riders have told the thread how we are at a similar bar-saddle drop to where we were when we were young man cyclists. That should be enough to demonstrate my point.

Age and other aspects may affect my current cycling ability, but I want my fitter to fit me according to what MY body actually needs, not to give me certain fit characteristics based on how, for example, older riders are assumed to be different from younger riders. I can agree that natural variations in body proportions should be considered in relation to individual bike fit, but age? If the fitter has assessed for example my flexibility, he/she should fit me according to my flexibility, not according to my age. In other words, fit me to my actual functional needs and abilities, not according to assumptions of averages related to "older riders." And fit yourself similarly, being driven by what you actually need for your health as a cyclist. Focus on what is known about fitting, not what is assumed about older cyclists.

I think there may be a logical order in which it is best to address the design of a frame. I think one of the most fundamental constraints is saddle position: seat tube length, seatpost height, its angle, and the resulting saddle setback which affects leg geometry and balance. One should also consider how the saddle setback may affect the effective saddle height, using the mathematics of a right triangle. But I'm not trying to design or fit bicycles, beyond our own.