I have ridden 105 miles in a day; it took me about 5 1/2 hours and I was wiped out for 3-4 days. Those guys do that same distance in less than 4 hours, keep going for another 30-40 miles AND they do that every day for 3 weeks...PLUS they do another 20-30 miles a day during warmup/cooldown each day. Those guys pedal 20,000-25,000 miles a year.