I'm a mostly fit kid 16 years old i need aton of help with endurance i can sprit decently but i cna't keep it up for long at all. especialy with racing and stuff i was wondering what i could do if anything that could help me.....PS i have asthma and i take an inhaler 2 times before i run and still get some attacks which is dumb Thanks alot!!!
as for the asthma maybe you can try some of those pills.
for distance though you just have to train distance.
alternate throught your days. ex:
mon: fast 1 mile
tues: slow 5 mile (recovery)
wed: some long speed work again
thurs: again more miles but slower pace
fri: speed again
after doing that a couple weeks you should have built up great endurance.
i don't want to put this site down at all, but you may want to look at a sight that is geared more towards running rather than weight lifting