Last night, I tried on my Nike Air Cross-trainers. They felt very comfortable, but there's one problem..dust on the floor will make it slippery. What I end up doing was wiping the bottom of my shoes before each serve. Very annoying, but after I wipe..the grip is great, I can get it to make a squeaking sound. The problem doesn't occur with my old Adidas cross-trainers though..the grip is good even though there's dust. But the problem is that my foot slips inside the shoe..might be that the shoe is just slightly too big. Anyone know why my Nike Air Cross-trainers lose grip from dust?