is it necessary to jump on a topspin serve? When i don't it seem to hit the net way to often and i end up double faulting. Is my technique wrong? Btw my jump isn't a forceful jump like in a jump serve. Its more like a push from my legs. I was told that if im doing this i loose alot of power and i need to be more planted on the ground. Im 5'5 and use cont grip on serving.