Not the first article i've seen about runners using cannabis. I partially disagree with the whole detrimental effects side. But I don't take it directly before exercise either. I think vaping before exercise isn't ideal. It's clogging your lungs up a touch and makes it harder to take in oxygen and gets you a little more out of breath while doing cardio. But if you use it a couple of hours before it's a different story. For me, I find the effects useful. The relaxation, the slight analgesic effects, the concentration, are all effects I like when I am lifting. I usually do a good hour of lifting, mostly dead lifts and some general core exercises, but ultimately focused on upper body. Then do an hour of legs and maybe 20-30 mins on the treadmill or bike to finish. There is a difference between a few hits on the vape a couple of hours before and none. I leave the session feeling better if I vape beforehand and I can maybe go a little harder throughout the session, say lifting to 130kg instead of 120kg. It does not make me superman, but it does have some positive effects.