I've always smoked, so wouldn't be able to tell any difference. Been pushing myself about in a wheelchair for 37 years, many of those maxing out up hill and down dale; also, I intensively weight trained for about 10 years. I was sometimes spotted thrashing up a steep hill with a RYO smouldering in my mouth, did peoples' heads in.
I think anything that gets you into max breathing for substantial periods is going to clear out any crud from smoking - but possibly warm-up periods become more critical. I always had to get "over the hump" in the first 15 minutes of intense activity, then I was fine.
Nicotine also helps mental acuity, which is probably beneficial in many sporting activities.