Stick to a vape or edibles for the most part if you can. Smoking pot will deposit tar in your lungs thus decreasing aerobic capacity, however if you run enough and smoke little enough you won't really notice anything. Personally I never enjoyed going out for a run while I was high, I felt lethargic and unmotivated and had problems with regulating my form. My favorite was smoking Saturday night with my friends after a meet then going out and hammering a 13 miler Sunday morning. THC is a natural anti-inflammatory and was noticeably effective on my runs after a long night of smoking blunts. I would suggest keeping a leash on it and not turning into a loser who sits around and smokes pot all day. In addition to this, if you are or soon will be running at an NCAA program, you can dodge your drug tests by chugging water the day before and of so that your results will come back inconclusive. Its likely you'll be tested again the following week, so after that first test just don't smoke the next week till you pass your next test.