It seems to be believed widely that, after shot (forehand for example) the arm should extend out towards the shot, making it almost straight. http://www.youtube.com/watch?v=YSWuA2MVEtA here's a pro making such a suggestion Over the past few weeks, I've made a point of keeping the bend in my arm constant, and my forehand has gotten much more consistent and powerful. When we prepare for a shot, our arm has a bend in the take back. I think the shot becomes much simpler if that stays there throughout the stroke and follow through. There's a lot more ways for the shot to go wrong if a player is starting with a bend and straightening it out at certain points. I began looking, and noticed most pros are keeping that bend in their arm like I have started doing. http://www.youtube.com/watch?v=9dihL0_w6IM&feature=related http://www.youtube.com/watch?v=S0-P4QzNuz8&feature=related http://www.youtube.com/watch?v=mMji0Wq5BtM&feature=related So, I think extension is at least misunderstood. Someone can probably explain how this method still achieves extension, though. My advice, however, is to keep your arm bend angle consistent throughout the take back and stroke.