I serve from a pinpoint stance. When I slide my front foot forward, I cant seem to get it to plant. It juts slides forward w/ to where my right and left foot toes are right on the line, and I am facing the net. This is killing all the power that I build up with my shoulder rotation, becuase I am only able to use half of it. Can anyone help me solve this problem? any drills? Should I place an obsticle in front of my feet, to keep myself from sliding my back foot too far forward? I have a good serve... and can serve around 90mph, but I feel like im loosing SOOOOO much momentum.