Need Help powering-up an object with KeyEvent like the plunger in PinBall

I’m creating a Golf game and I have several _mc’s with a golfer swinging a club…front view, side view, back view… I have them set up so the user can move the golfer around the screen with the arrowKeys. The spacebar activates the golfer to swing the club…But I would like the user to have more control over the amount of swing the golfer can take…ie. (full-swing, half-swing, quarter-swing, etc.)I have played several games were the space bar can be depressed for a few seconds to power up an object…the first one that comes to mind is PinBall, were the plunger is pulled back slightly with holding down the spbar for a short time, or it is pulled way back the longer you hold the spbar down. The code I have now is a basic KeyEvent Listner…
keyListener = new Object();
keyListener.onKeyDown=function(){
if(Key.isDown(Key.SPACE)){
gotoAndPlay(2);
}
}
Key.addListener(keyListener);

I have searched through a ton of Tutorials out there, and no where is there an explaination on how to make this happen.

Thanks for anyone’s help in advance!