If we take the premise that concentration is important then where does relaxation come in?
“..Players who are able to relax in brief moments of inactivity are almost always the ones who end up coming through when the game is on the line. This is why the eminent tennis players of their day, such as Ivan Lendl and Pete Sampras, had those strangely predictable routines of serenely picking their rackets between points, whether they won or lost the last exchange, while their rivals fumed at a bad call or pumped a fist in excitement. ... Remember Michael Jordan sitting on the bench, a towel on his shoulders, letting it all go for a two-minute break before coming back in the game? Jordan was completely serene on the bench even though the Bulls desperately needed him on the court. He had the fastest recovery time of any athlete I’ve ever seen. ... The notion that I didn’t have to hold myself in a state of feverish concentration every second of a chess game was a huge liberation.” (Josh Waitzkin)
Where are the moments when you can unplug in between?