Proof =
Steroid use is optimal for running fast.
Bulking up without doing specific (to an event) running training is not optimal for running fast.
Beefy.
Hear me out, maybe training by doing non-pull-ups until failure, burpees, and then maxing out on bench and the deadlift every other day with a little 6x1 minute HIIT workout or an unreasonably slow 5k run with a weighted vest on as your cardio workout isn’t how to get better at running. Throw steroids onto that and these people are now all very good at flipping tires and doing fake pull ups because that’s what they train for.
Throw steroids on top of regular mileage, sprinting, threshold work, and plyometrics/lifting that work your posterior chain as well as your running range of motion and suddenly you’re a lot better than the person that’s doing the same thing without the steroids.