Dixout for Harambe wrote:
I understand that, as they don't have the pounding on the legs factor.
Now what keeps a runner for elevating his heart rate for the amount of time you listed above daily from training? Why would running for 11-12-13 hours per week then cycling for 25-28 on top of that have a detrimental effect (or a positive supplemental effect)?
Well, for starters, if a European Pro can top out at 28 hours per week, do you think that a runner (no matter how talented) could put that amount of cycling on top of 120 miles per week? He could not.
I could go on and on about how sore your crotch gets, and how sore your supporting muscles get, and how tired your quads, glutes, and calves get, but I won't.
I should also explain to you that cycling training JUST builds mitochondria in the working muscles (i.e. the quads, calves and glutes) just like running does, or swimming.
Do you know why Micheal Phelps is the greatest swimmer of all time, but just an "OK" 200-pound runner?
Mitochondrial development in the WORKING muscles.
Short answer: doing extra hours of "aerobic-training" that isn't running is of little value.