I'd imagine massaging would be more about a combination of inteligence and strength rather than a single skill in of itself. Considering giving a massage is more a combination of just knowing where specific points in the muscles are and being able to apply just the right amount of pressure to loosen said points than any actual technique this would make the most sense. While there are classes for that sort of thing you won't learn anything there that you wouldn't learn in a basic below college entry level anatomy class.