Hey guys I just made a video of me hitting some groundstrokes in my basement. I use a soft stress ball to hit against my wall because its already cracking because I used to use a tennis ball to hit against it. It is exactly like a tennis ball in regards to size, but its just a ball of foam instead of an actual tennis ball. It bounces slower and it actually lets me hit hard against my wall. http://www.youtube.com/watch?v=ljbsUmsVPjI Any critique or advice on my groundstrokes are welcome, thanks.