I heard your opinion, I think you wrong, so are many other teaching Pros. But tennis is different for everyone, do what you feels right. That is what it is all about. I was just taken back by your advocating this is a better, or a right way of doing it - which is not true.
"Bending of arm after making the contact with the ball is quite natural and obvious" - for you maybe, but trust me, for a beginner or even and intermediate player is not so obvious. In fact, most of them attempt to straighten the arm towards the target, leading the ball.
As for Federer, he has many forehands. You are taking one data sample and making it the rule. This is not true. He hits with double bend and reverse too.
http://www.youtube.com/watch?v=b_XamJSL ... re=related
Look at the first one, pause at contact.
He does, like I said earlier, has the arm straighter then most double bend, but there is a bend in lots of his forehands, a visible one too. Most times it happens on cross court shots. On inside out forehands, he straightens his arm completely, although I still think there is no elbow lock, at least not deliberate, intentional, thought out, it may happen because of the forward momentum and it is there while the bicep is rather relaxed, then it flexes right at contact and unlocks. Hitting with locked elbow just has little to no feel.
Same video above, look at 1:00 minute on. This is the forehand where he moves away from the ball, running over to hit a Forehand. This is the ones he straighten the arm completely on. Again, arm straight, but bicep flexed during contact. Flexing bicep releases the "lock" on the elbow. So he first initiates the shoulder turn, lagging his racket behind a bit. The distance from the ball (contact point) causes his arm to straighten. Right before and through the contact he flexes the bicep and ACCELERATES through the ball. It is physically impossible to accelerate with locked elbow through the ball at that point.
Same video, pause at 1:37 Look at that contact point. Look were it is. There is no way for him to hit with anything but a straight arm here. Do you think this is something a beginner or even intermediate player can replicate? The contact point is way out in front and away from the body. Anyone without a solid strokes behind him and years of practice simply cannot replicate this. Taking a step closer and hitting a double bend on this ball is possible even for a beginner.
Same video, 2:48 and on, look how he "throws"/ "pulls" his arm (that is straight) into the shot by virtue of shoulder turn, but when he is about to contact he pronates and flexes. Keep watching the rest of the slow motions, the INTENT is not to lock your elbow on contact, quite the opposite, if anything, it is the RELEASE the lock into the contact, the lock that "may" happened by keeping your arm lose and initiating a violent but controlled shoulder turn.
I am happy to discuss this further if you wish. I am looking at things a bit different here. I am looking at what would a player think of when doing something like that? ...thinking about "locking" the elbow on contact to me is as bad as it gets. A sure way to destroy the existing stroke or a sure way to NOT develop further. What I would do is try and find a comfort zone for a player by moving his contact point. I would ask him to try make contact with the ball a bit in front, maybe a bit to the side as well. See the result and go from there. Basically find a natural contact for that particular player. It is a process. There is no magical "lock your elbow on contact and all is well" here, this is an internet myth, a "ShamWow".
Level 13 Edberg and counting...