wow, you qualified for Boston? AMAZING accomplishment!
(fyi: men have to run 26.2 in less than 3:10 to qualify)

both riding fixed and running can be VERY hard on your knees if you don't know what you're doing.

they can both be good for your knees, but you have to be smart about it. for running that means starting out easy and upping your mileage VERY gradually. hereditary biomechanics also play a big role.

i think someone coming from a cycling background is likely to have a lot of the same initial pain as someone coming from a sedentary lifestyle. once your tendons are used to the punishment i bet you'll find it gets easier faster.

edit: congrats on qualifying for boston aeroplane.

The best cross racers are also runners. I run 15-20 miles a week in the off season getting ready to race. Riding a FG will only make you a better FG rider.

i am going to get back to running very soon as part of training for the beach2beacon here in maine...i want to keep biking as well as running and some swimming too

rollerblading uses different muscles too and i found that out this past weekend after skating for three hours at the skatepark...so i am hoping to get a lot of skating time in as well...well rounded workouts i would say

+1

if I could just shave a mere 45 minutes of my marathon time I'd be there too........I guess there's always charity.