I've looked into it a little bit. There can sometimes be politics mixed in science, with scientist bias creeping in, ignoring data or highlighting data according to their prejudices. I think there may be that in this instance as well.
But on this issue, I think Andrew got a little bit confused about what he's heard.
There are studies that are trying to say that cold water would make it harder for weight-lifters type of athletes, who are trying to create bulk of muscle that isn't much useful in everyday life except to boost your ego. They say that it enlarges arteries. But this is known, everyone knows that cold water constricts blood vessels, but that is what makes them more efficient. So some of what the researchers are studying is based on their own bias. This one is 2006, bit older.
And there are of course other studies that contradict that. This one is 2015.
So it's going back and forth.
But basically, where it seems to be going is that cool water helps develop slow-twitching muscles, which are the muscles you need for endurance, running, and such, the more useful muscles in life. And some of these studies are saying that cold water inhibits the growth of fast-twitching muscles, which are the high intensity, weight-lifting, etc. But again, it's still going back and forth, it isn't settled.
But I didn't get into this, I was just talking about soreness and recovery, and that is still legitimate, it's common sense, no controversy about it, at least as far as studies and science is concerned, and goes all the way back to Hippocrates. Cold water has been in use for therapy since the 1800s. Used to be hot water was a luxury, but we're used to it now, but it's actually not so healthy for us, not what nature intended for us.
Ultimately, though, the effect of cold water immersion on muscle growth may be somewhat of a moot point: The main reason athletes turn to cooling is to speed muscle recovery—something which is pretty well supported by scientific and anecdotal evidence, Pino says. Cold water constricts blood vessels, helping to flush by-products (like lactic acid) out of your lymph nodes and lower inflammation, both of which help reduce muscle soreness.