Just keep trying and working hard, first time my mate did 100 mile with me he was in sh!t state, threw up 3 times, soiled his chammy shorts, but he's stuck at it, while i've been doing more running, he's stuck to his cycling (he has a spinal condition so finds running painful) and has just returned from a cycling holiday in Majorca where he's covered 80 miles everyday.
If you have the desire and work hard, you'll crack it![]()