Its easy.

Most people pick up a bass off the store rack or off the internet and just LEAVE THE BRIDGE SETUP. This is a perfect example of what I DIDN'T DO to train my fingers for speed. What I did instead was set the action either up 1-2mm, up as far as 6-8mm, or somewhere in between depending on how much I wanted to 'work out'. Just by setting the action and working at insane speeds, when I lower the action, I don't have to work as hard; meaning I set myself so low after my workout regimins (i.e. for concerts, gigs, recording) All I need to do is tap a fret to set it off. You will be suprised at how much effect it has on your playing speed with your fretting hand!

BUT! Like any other work out regimen, this should NOT be overdone. Better training in bursts and have proper hands than training all at once and screwing up perfectly good fingers for a long while! Believe me, I did it at first. Don't push it. You will thank me later!