The word, “lateral,” defined by Webster as “pertaining to the side,” has two applications in hunter seat riding. “Lateral aids” refers to the use of the rider’s aids on the same side of the horse, such as the right leg and right hand. This is opposed to “diagonal aids,” which are applied on opposite sides of the horse, such as the right leg and left hand.
“Lateral movements,” however, refers to any suppling exercises which are used to lessen the horse’s stiffness from side to side. They range from the simple circle to more difficult movements such as the modified pirouette or half-pass. Even bending a horse around the corners of a ring can be said to be a lateral exercise, for it affects the animal’s suppleness from side to side.
You can find information–including text, photos, and diagrams–about specific lateral movements in my latest book, the fourth edition of Judging Hunters and Hunter Seat Equitation, available at:
There are several new Equitation Tests added to the 2022 show season that are lateral movements, and all are discussed in depth in the new book.