An Interview with Trainer, Larry Whitesell.
There is a common misconception in the non-gaited horse community that gaited horses are forced into their respective gaits. This is false. Gaited horses are born to naturally move the way they do. However, it's not quite as simple as that. You cannot simply hop on a gaited horse, or any horse for that matter, and just expect them to move out in the correct manner. It takes training, and the proper muscle development to hold the gait.
Trainer Larry Whitesell does a great job explaining the gaited horse and the training concepts needed to properly develop the gaits.
Reference:
CRK Training, https://www.youtube.com/channel/UCtXIfsEEZulPHDycFOQFmtg, Retrieved Oct 17, 2017