I've recently upped my walking/running to between 4-7 miles per workout, (from doing 2-3 per workout). I'm not really having any endurance issues, but I feel so stiff the next day Is it because I'm not stretching/warming up enough? Any tips about this- what do you do prior to your workout?

Do you stretch afterwards? From everything I've read, stretching before is pretty much useless. Stretching afterwards, however, is crucial. I stretch for a minimum of 5 full minutes after every run. I was always stiff the next day when I didn't stretch, now I have no problems.

These are great stretches... I do 5, 7,8,9. and 10...

i never used to stretch but after running i always make sure i do. i think it really makes a difference!