I guess if you are 4.0-4.5 as a junior, you went through some training of using continental grip to serve. You can go back to follow the official serve grip, or using your forehand grip to serve to the next level. Many posters on this thread don't believe this because they have a mental barrier to seriously try it. It is easier to using eastern forehand grip or semi-western grip to serve than using eastern backhand grip (#1) to serve, using the same modern techniques. Who said one cannot do pronation if you are not using continental grip? On the contrary, one can do more pronation using #3, #4 grip than using #2 grip. Just take a racket and face a mirror, you'll know immediately my assertion is true. Labeling #3 and #4 grips as beginner grips is totally wrong. Currently, the stance is opened somewhat at elite level, the grip is also opened a bit by Stan. This new beginning is not the end, as many of posters here like to wish. Tennis players have been using #2 grip to serve in more than one hundred years. All coaching has been concentrated on #2 serve grip. This created a big myth, the closeness myth for tennis serve. I made this thread to crack this myth.
Think about this, more than half of tennis population are using a non-#2 grip to serve, some of them may have tried one or more times in years to use #2 grip to serve but failed. Is there any biomechanics study to prove one cannot have effective serves using grip other than #2? If anyone can provided one, please let all f us know.