Myo-Stat and muscle fiber type

Im as anxious as hell to see if this stuff works, in fact I picked up a couple bottles of Myo-Blast from a buddy that works at a GNC… my only question is what TYPE of muscle fibers does this new wave of supplements (myo-stat,myo-blast, etc…) promote the growth of, fast or slow twitch. This is of interest to me because im involved in a sport that puts a high premium on explosive speed, and i wouldnt mind having a few more fast twitch muscle fibers.