An individual who truly understands the horse's natural physical and psychological needs and holds this as the highest  priority when keeping, working with, riding and training horses. It means learning to ride naturally and conscientiously so as not to harm the horse's body, mouth or hooves.

Trainers who use artificial devices, pain to motivate, refuse to train barefoot horses and agree to ride horses under age 3 are not good choices to train your horse. Pick someone with good references, that you have observed several times and that is OK with you watching the training sessions.