The problem with gum soled indoor shoes is they grab the turf too much. Because they don't slip out, force transfers to the knees which can result in ligament damage (torn ACL). That's why I play in gazelles because they have no grips on the sole. The flat sole grabs the turf just fine but has some "give". Although they wear out faster and don't offer as much support, they're comfortable and about as safe a shoe you'll find for indoor soccer.
Recommend this product?