This is a bad idea for at least 2 reasons.
1) Half life. So you take it - and get a VERY mild 'kick' in the gym. But it's still in your system hours, days and weeks later (in lesser and lesser amounts obvs).
2) All of the usual dbol side effects
There's more. There are other drugs which have similar half lives but the sides are even worse.
3) Steroids as a pre workout...??