"The key to winning is poise under stress."
1 : a stably balanced state : EQUILIBRIUM poise between widely divergent impulses -- F. R. Leavis>
2 a : easy self-possessed assurance of manner : gracious tact in coping or handling; also : the pleasantly tranquil interaction between persons of poise
poise of the meeting> b : a particular way of carrying oneself :BEARING, CARRIAGE
synonym see TACT
Fashion magazines will tell you that runway models need to be poised, so you might think that poise is all an act, but really it's about being comfortable, unflappable even. It's about being stable.
Coach Wooden says that his definition of poise is simply being yourself. Not acting. Not pretending to be something you're not, you are who you are and you're comfortable with that. You'll function at your own level of competence. Granted, as a cheerleader you may sometimes have to pretend to be happy and you have to work at being positive- but if you have enthusiasm (love/spirit) then you'll be able to smile and act excited and still be genuine even when life is hard or you're having a bad day.
Poise means that your goal is not to satisfy anyone else's expectations but your own. You give your total effort to becoming the best you are capable of being.