I'd tend to agree with MetalPedaler on this one, but only on the basis of the experienced athlete being more efficient than the inexperienced rider. The difference in energy expenditure with experience is more pronounced in some activities than it is in others. For instance, not being much of a swimmer, I'm sure that I use much more energy to move through the water than my wife, the ex-life guard. I doubt the difference is as pronounced for cyclists, but I think there is some difference.