I was searching what people had to say about the impact of long running on sprinting/raw speed. And the basic gist is that for a sprinter a long run is not useful at all, and so they don't do it.
However I can't find a conclusive answer as to if it's just not useful for speed and won't make you faster (on 100-400m), or if it actually also slow you down and make you less fast.
Thank you,