Get an all-around workout in this new 25 minute P90X class, part of our half hour evening workout series. You’ve seen the infomercials. Perhaps you’ve done the popular physique-enhancing DVDs. Now you can do the extreme P90X workout here at the RSF with a certified P90X trainer. The true secret of how P90X works: Muscle Confusion. P90X uses targeted training phases so your body keeps adapting and growing.