If its workout music, then presumable then it has to constant high tempo, then i would suggest some Hawkwind. They are a British Rock band from the 70's, Lemmy from Motorhead was the base player, that will give you an idea of the type of music we are talking about. They are particularly good at very long songs, around the 10 min mark and they dont let off the pace. Master of the universe, Brainstorm and Orgone accumulator are particularly up-tempo, long and loud. LOL
Craig