Forehand: arm lag or arm unit turn with body?

[rusty75]

On my forehand, my friend had told me that my arm lags a little and that I should unit turn my arm and body together through the shot. Should the arm lag behind the body during the forward movement into contact or should the arm unit turn with body and only the wrist gets laid back?

 

[masterxfob]

depends on the shot. when i go for my shots, i definitely feel a greater whip/lag in my motion. when i'm rallying and moving the ball around, i don't feel as much whip/lag.

 

[Blake0]

It depends on how you hit. If you hit more modern, whippy, open stance forehands there is a little bit of lag, especially when you go for your shots.
http://www.youtube.com/watch?v=KB6EY7FxgUg
You can see the lag here pretty well.