Because a treadmill track is fairly flat,
just animate the texture moving around it,
not the tread itself.
You don't even have to worry
about having a seam on the texture
because a treadmill has one.
You can make the track frames (including a pre blur)
in an image editing program like Photoshop.
Save the files out as sequential targas or a Quicktime Movie (animation compression)
and bring those (or it) in as a texture on your treadmill track.
You could have two layers,
one for the texture map,
another for a bump map.
Here's an old file with a moving texture applied.
topSpinning01.mov