Re: Jump or not while serving?
Yeah it isn't really "jumping." Like Bernard_Black said, it is natural to come off the ground when you put every ounce of your weight into the shot. When you become a good, solid server, you SHOULD be coming off the ground because that means you are using your legs or back to throw your weight into the serve.
Federer / Haas / Safin / Gaudio / Kuerten / Youzhny / Nadal / Gonzalez / Ljubicic / Hewitt / Soderling / Wawrinka / Coria / Nalbandian / Kohlschreiber