Athletics... running... legs knotting... help? btw i will give you best answer if you have fast relief ideas!?

ok in athletics... we are required to run. i have the biggest muscleiest legs in the cl... but i am probably the most out of shape.,.. even though im in shape... i also have a muscley stumach that has a little baby fat stilll... and i hate athletics... btw we have had to run lately and my legs have been knotting up,,, any sugestions on how to relieve the pain to be able to run another mile tommrow?