Probably not, because the relevant bits are probably too disconnected. I've often dreamed of running down the road at ~50mph, complete with proprioceptive cues that I am running, and I can't say I've seen an effect.
I'm not talking just about dreaming, I'm talking about lucid dreaming and dream control. If you're not lucid in your dreams, then I don't think it's too ridiculous of me to assume that those dreams are "normal" for you, so you wouldn't expect to see any improvement, even if dreaming about things like that could offer improvement.
What I'm talking about is people who can realize they are dreaming, and then make a concerted effort to consistently use that time for mental training like the article mentions. That seems far more likely to yield results than sporadic running dreams.
Sorry, yes, I wasn't clear. I've been a natural lucid dreamer for 25 years now, to the point that I can't even remember the last time I had the "recognition" that I was dreaming... for me I long since just know, pretty much all the time. I'll cop I wasn't deliberately trying to exercise, but I doubt it'll matter.
Besides, this sounds like the sort of thing you can already do in your down time, riding the bus, sitting at your desk, etc. Regardless of how "lucid" you are, counting on getting anything like this done in your sleep is a crapshoot compared to setting an alarm on your phone and doing it during the day.
If indeed it works that well, which I'm still skeptical about. Common sense suggests that if it were this easy we'd have collectively discovered this as a race a long time ago. (Kinda like Larry Niven's arguments about why humans almost certainly don't have psi powers... if they worked, we'd know. The very fact we're "wondering" is strong evidence that there's nothing there, or the effect is so small as to be useless and essentially undetectable.)
