Importance of Lateral Work
“Lateral movements” is the term that is used to designate exercises in which the horse moves not only forward, but also more or less sideways. They are introduced after the horse has learned to bend and turn on a single track and should be viewed as variations on the general theme of the basic gaits, not as separate, unrelated “tricks”. Lateral movements are developed within the walk, trot, or canter by moving either the horse’s shoulders or his hips off to one side of the track that is being followed, while bending his spine, and engaging the hind leg underneath the body mass that has to cross over as a consequence of the oblique angle of the horse’s body to the ridden track. This leads us to the general hierarchy of priorities that must be observed in practicing lateral work.
A pure, high quality walk, trot, or canter must be established before the lateral movement is started.
This quality gait has to be ridden on accurate arena patterns.
Only when the horse is going in a good quality gait and along precise arena patterns, the lateral movements can be added on top of this foundation.
Well ridden lateral movements are elegant, graceful and beautiful to watch (and fun to ride), which is why they are included in exhibitions and competition tests. However, they were not invented as an end in themselves, but as a gymnastic means to an end. They fall under the topic of bending the horse in motion, which begins with simple curved arena patterns, such as circles, corners, serpentines, and turns on a single track. On these curved lines, the horse’s spine has to bend so as to form a segment of the arc of the pattern that is being ridden.
As the next level of difficulty in bending in motion, lateral movements are introduced to the horse as soon as he has mastered bending his spine along curved lines on a single track. Lateral movements have always played a key role in the training of the dressage horse, because they help the rider to develop the horse’s natural gaits by isolating a specific hind leg and engaging it, suppling it, and bending it underneath the combined body mass of horse and rider, which will then in turn improve the suppleness of the back, the neck, and the poll.
Lateral movements can be used to improve the horse in many ways:
They improve the horse’s agility and maneuverability.
They improve the horse’s attentiveness and responsiveness to the aids.
They improve the horse’s suppleness.
They improve the horse’s balance.
They improve the horse’s straightness.
They allow the rider to engage and bend each hind leg individually.
They unlock the horse’s hips due to the crossing and engaging of either the inside or the outside hind leg.
They unlock the horse’s abdominal muscles due to the required lateral bend of the horse’s spine.
They strengthen the muscles on the inside and outside of the hind legs and front legs.
They increase the horse’s shoulder freedom as a result of the increased engagement and flexion of the haunches (i.e. collection).
Source
This is a nice explanation but the only thing I would change is the “requirements to begin lateral work” bit.
“A pure, high quality walk, trot, or canter must be established before the lateral movement is started. This quality gait has to be ridden on accurate arena patterns. Only when the horse is going in a good quality gait and along precise arena patterns, the lateral movements can be added on top of this foundation.”
This is assuming the horse is naturally talented and can find its balance in all gaits easier than the average riding horse. The average horse may not be able to produce high quality gaits and accurate figures without lateral work to supplement the horses schooling.
