Ventroflexion is when the horse hollows his back. Usually accompanying ventroflexion is a high head.
A little ventroflexion is required for the tolt (rack); much less than required for the pace. Too much is not good, and may affect the long-term soundness of a horse. Finding the fine line between a little and too much may take time, patience, and experience, but your horse will be ever so grateful!
Riding a horse by forced ventroflexion creates more stress and tension on the horse's back and legs, a cramped neck, and may impair breathing and swallowing. We often wonder if it has something to do with the hock problems (spavin) that plague Icelandic Horses.
Almost any horse of any breed, including non-gaited breeds, can be forced to "gait". If forced and held in ventroflexion with a high head, the resulting gait will be a rack (same as the tolt).
Notice the brace in the neck and the overdevelopment of the brachiocephalicus (under side of the neck). See this image for details.
This image shows an Icelandic Horse with more roundedness, able to work thru his body.
A horse can tolt with a little bit of ventroflexion, and a nicer neck than the first image. See the page on neck muscles.
It's a good idea to teach the horse to round his back in the other gaits before working on tolt. This eliminates the possibility of the horse always taking on the ventroflexed frame in other gaits. It is also good to vary the gaits when riding to give relief to the back and muscles that are affected by ventroflexion. Switching gaits keeps muscle fatigue at bay.
The following are two images of the same Icelandic Horse -- one at the walk with a more rounded frame, and one at the tolt with ventroflexion. Notice the change in the topline; and how the withers are lowered when the head goes up.
Mary Wanless might ask: "How would the horse land on the riding arena if we chopped her legs off? You’ll see that she would not plop neatly down onto the centre of her tummy, as a well-balanced horse would." This is indicative of a horse on the forehand.
Pleasure riders will not want to emulate the extremeness of the tolt of show or competition horses.
Long and low work will help build up the proper muscles. These muscles may include the shoulder sling and the pectoral slings. Mary said of her pacy horse: "My hypothesis is that "proper" work, i.e.
down and round, instead of extreme ventroflexion changed the muscle
mass in the withers area and hence the gullet plate width of his saddle."
Work on the "head lowering" exercises is very beneficial for horses who have gaits that require ventroflexion (stepping pace, saddle rack, corto, largo, etc.). See the head lowering page.
Ventroflexion may happen more readily with a heavier weight rider on the horse's
back. This should only happen in a horse that is more flat or round or
trotty to begin with. It would not be wise to have a havier weight rider on a horse that tended toward paciness.
About pacey horses: Look
at the saddle you are riding in and check to see how sore your poor horse's back is-- if he's sore, it's no
wonder he is pacing--he may be so ventroflexed from the pain---there are so many
kinds of abuse.
The truth is many of those so called show horses are really quite square and
in fact have been taught to pace or swing--once the muscles have become
ventroflexed they pace flatshod--BUT reverse this and they go to their true