I do a lot of mental toughness training with my athletes.
“Never let them see you sweat” really means something when you are playing at a high level.
For example, take wrestlers. When you see a match and the 2nd period ends, if one wrestler is slumped over, breathing hard and not even looking up, you can guarantee his opponent sees this as his opportunity to take the match. It is the mental edge. The opponent is “energized” just from watching this negative posture. It makes all the difference.
So how do you train for this toughness?
It could be ongoing suicides with the prowler, it could be high rep kb training, it could be hitting a max effort attempt.
What I like to do is near the end of a high intensity set, while your athlete’s face is grimacing, contorted in agony, tell them to not show any emotion. Go straight faced and “never let them see you sweat”. It works!
At the very moment when they are weakest, they appear strong. This is the edge and it builds confidence.
To see more on the importance of mental toughness training, see the following article.