Originally Posted by isilra
I'm so stupid that i have never realized that the shoulder and the arm should stay in the same plane and the racquet should be the only one who should come from behind. I was always ruining my kinetic chain by trying to keep my arm and elbow back when i turn my shoulders. I'm so glad that i made this thread. It's like i have found my missing son after 20 years of search lol, thank you man.
you want 'racquet lag'. not 'arm lag'. notice how djoko's/fed/nadal/anyone good keeps the upper arm in line with the torso during the swing. the upper arm is moving with the torso/shoulders. the forearm/wrist is loose and lags the racquet.