Originally Posted by anubis
I like what LNR is trying to teach, even if it's not 100% the case all of the time. Many amateurs (myself included) swing first with their arm and the rest of the body often follows. LNR is trying to show that you don't have to always lead with your arms, you can lead with the uncoiling of your body and allow your arm to follow.
You're still using your arm, but it's following the motion of your body -- not the other way around.
He's exaggerating in order to illustrate the point. I'm sure if we watched him in match play, his right arm is not passive -- but he most likely is rotating his body with his arm following that rotation.
I think you're exactly right with that.
And most professional players do indeed generate most of their power from the legs and core.
You might have noticed that many pros have relatively thin arms. Federer is not going to impress any chicks with his biceps. Nadal used to, but his arms look a lot thinner than they used to be. Tsonga also looks like he lost some upper-body muscle the past year. A lot of other players look really thin, and you really wonder how can they hit such powerful shots.
But all pros have strong legs and rock-solid abs. Don't take my word for it, ask your wife/gf, they notice this stuff.
That's because most of the power behind their shots comes from the core rotation.
This does not mean that the arms are just completely limp and flapping around the body, but the muscle tension in the arm is only as much as is needed for directional control, not for power.