I've been watching the 1980 Wimbledon final between Borg and McEnroe, and noticed that Borg (and McEnroe, but less frequently) tends to blow (or sniff?!) the fingers of his left (I think) hand between points.
Is there a practical reason for doing this, or is it just a quirk that helps him stay centered between points?
Is there a practical reason for doing this, or is it just a quirk that helps him stay centered between points?