To put it simply--runner's have to contend with gravity, but swimmers do not.
Wisconsinite wrote:
Please, please, PLEASE find me an Olympic track athlete who runs 4 hours a day. Do you not understand that running is an "impact" type of exercise that has negative effects on your bones and joints? It is physiologically impossible to run at a high intensity for four hours every single day.
You have to be older to be a distance runner because you need to build a large aerobic base on limited running time(this takes upwards of 5 years).
IF runners were able to pound mileage for four hours per day, I guarantee you we would start seeing 18-year-old medalists.