[Donald Lee]

Originally Posted by Mike Prevost

Most adaptations that affect performance are inside of the muscles. The central adaptations are less important when it comes to performance. For example, only a small percentage of the most fit athletes actually desaturate (less than 98-100% oxygen saturation on hemaglobin) at max exercise levels. Even these athletes are rarely doing any event at this intensity level, even in a shorter event like a 5K. As a result, we are almost never limited by central adaptations, which argues for a focus on training specificity if you want to perform.

Mike,

I posted what you wrote on another forum and got this response:

There has been a debate for years in exercise physiology about whether the limiting factor in aerobic performance comes from the cardiovascular supply side or oxygen utilization within the muscles themselves. There are arguments for both sides within the literature and I don't think there is really a clear answer yet but regardless, performance depends on both supply and utilization as well as contractile properties of the muscles, technique and skill, etc. It's probably a bit simplistic to say there is any one piece of the physiological puzzle that is single most important. When it comes to performance, it's all important.