ok, take two guys who train based on time; I'll still put my money on the guy training on hills to become a stronger rider more quickly than the one training on flat ground.

and you cant's say people don't train on distance, everyone I know around here picks a route (pre-determined distance) and they go ride. All they have to worry about is getting home before dark; which they almost always do.

also someone explain to me why it is that when I started riding again in January after a ten-year hiatus, an 8 mile ride took me 45 minutes (on hills) while my flat-lander buddy who has been riding every year for the last four was already riding 20 miles (on flat ground). Now after a season of training, I can run away from him on flatland rides even though he has ridden over 1600 miles this year compared to my 1065. we're not talking about a strictly controlled scientific experiement here folks, just guys who get out and ride (like 99% of us) -- frequent and consistent hilll training will result in you becoming a stronger rider than doing even more miles on flat ground.