I am sure you can catch fish on a tube moving it against the current, too, but
it is not as natural as fishing it with the current. When fishing a boot tail
or curly tail grub against the current you will get more action - more
vibration. It may look more like a fish struggling, but with tube going
against the current it will just slide along - maybe not a bad thing, but
different from the grub.

I fish the Flint River near me some, and I can catch bass on Shadraps most
often fishing it with the current, but fishing them against the current gives
them more action and makes them dig deeper. That seems to excite active bass.
Ronnie

http://fishing.about.com