Valium IS NOT a muscle relaxer. It is an anti-anxiety You DID NOT get put on it for an injury dude. If you choose to take it, fine but be honest about it. Hell, I like an occasional valium with my Jack Daniels in the morning.
It will DECIMATE your workout and motivation. It has the longest half-life of pretty much any drug - about 14 hours and stays in your system forever. IT'll cause drowsiness, a lack of motivation and is the only drug that stops me from waking up with a stiffy.
You want an opinion? Shoot dope before taking valium dude.