Each gait has its own potential for rhythm impurities. The walk is the most vulnerable to gait impurities because it has no suspension phase. That’s why German riding instructors often warned against working the horse at the walk.
The canter has an asymmetrical footfall sequence, which also makes it susceptible to rhythm purities.
The trot has a very symmetrical footfall pattern with a suspension phase after each diagonal pair touches down. That makes it the most robust gait, although there a couple of rhythm anomalies that can occur in the trot as well.
Walk
In a natural walk, the horse moves his feet in 4 clear beats: right front - left rear - left front - right rear.
When the rhythm of the footfall is disturbed, there is either a shift towards a lateral sequence in which the left pair of legs lifts off and touches down together, followed by the right pair of legs, or there is a shift towards a diagonal coordination, which is similar to the trot or the piaffe.
Lateral walk
In the lateral walk (pace) the footfall sequence is altered from a clear 4-beat pattern to a 2-beat pattern in which the left pair of legs moves together and the right pair of legs moves together. It is caused by tightness in the horse’s back and bracing with the rib cage.
There are horses that have a natural tendency to pace. There are four gaited horses whose extra gait is the pace, and there are three gaited horses who have a genetic predisposition to pace, as it runs in certain blood lines. These horses will sometimes lateralise their walk even when they are moving around freely in the pasture.
The pace can be caused by the rider, for instance if the rider sits very heavily and elevates the neck too much and then tries to “collect” the horse with the reins from front to back.
It can also be caused by a rider who pushes the horse forward with her seat bones.
Both make the horse drop his back and brace the musculature around the back and rib cage.
In the natural walk, the front leg stays on the ground until the hind leg of the same side has almost arrived, and it lifts off just in time not to be hit by the landing hind foot. In the pace, the front leg doesn’t wait for the lateral hind leg to arrive, but lifts off almost at the same time as the hind leg.
To restore the purity of the rhythm to the walk, there are several things the rider can do.
The first one is to relax the muscles around the pelvis and to feel the forward-backward movement of the horse’s back and the lateral swinging of the horse’s rib cage. If the rider’s pelvis is stiff, it will impede the movement of the horse’s back and rib cage.
A pacing horse’s rib cage is stuck so that there is very little lateral mobility. Freeing up the rib cage and restoring the pendulum like swing from side to side is an important part of repairing the lateral walk. This is easier on curved lines than on straight lines, and it’s easier in lateral movements than on a single track. Voltes, figure 8s, and serpentines are therefore especially suitable arena patterns for repairing the walk.
Asking the haunches to yield to the outside of the circle or volte requires a more pronounced movement of the rib cage, and it enables the rider to speed up the inside hind leg so that it lifts sooner.
In addition, applying a stirrup pressure when the inside front leg is on the ground can delay the lift off of this leg.
Combining voltes with the shoulder-in position and stepping into the inside front leg are very effective in restoring the purity of the walk.
Walking over ground poles and cavaletti can also be helpful.
Jigging
The jig is a gait abnormality in the walk that is caused by the hind leg lifting off too soon, and not staying on the ground long enough. This leads to the hind leg lifting off at the same time as the diagonal front leg, whereas in a natural walk there is a delay between a front leg lifting off and the diagonal hind leg lifting off. The result is a diagonal footfall sequence that is similar to a trot or a piaffe, but whereas the horse’s back and withers are raised and the rib cage is supple in a good trot and a good piaffe, the back and withers are dropped and the rib cage is braced when the horse is jigging.
This can be caused when a rider has very tight muscles around her pelvis so that she can’t accompany the swinging motion of the horse’s back and rib cage, and when her own energy level is too high. Riding front to back in an attempt to shorten the strides or to collect the horse with the reins can lead to jigging. Horses with a hotter temperament are more likely to jig than calm horses.
Riding a slow motion walk on a circle in a shoulder-in position will help to return to a clear 4-beat walk. In a shoulder-in on the circle the hind legs have to cover more ground than the front legs, and if you ride the walk in a very slow, deliberate tempo the hind legs have to take longer strides.
The circle as well as the shoulder-in position also require a lateral bend which helps to mobilise the horse’s rib cage.
Another way of thinking about the problem of jigging is that the hind legs largely eliminate their pushing/extension phase by lifting off too soon. But if one hind leg is not pushing long enough, the other one can’t reach far enough under the body to flex its joints and support the weight properly, and if the hind legs step short they can’t support and protect the back. That’s why jigging horses always step very short with a hollow back.
Walking up hills can help to develop the pushing power of the hind legs as well. Walking downhill, on the other hand, requires more flexion and might actually increase the tendency to jig.
You could also avoid the issue altogether by suppling the horse in the trot and developing the pushing power by lengthening and shortening the stride in the trot or trotting over poles and cavaletti. When you return to the walk, the quality will probably have improved.
Trot
There are a couple of rhythm anomalies that can occur in the trot, if the diagonal pairs are not perfectly synchronised, i.e. if the diagonal pairs of legs don’t touch down together.
DAP
Diagonal Advanced Placement (DAP) is a term that was coined in the 1990s and generally considered to be sign of a high-quality, uphill trot. In this variation of the trot, the hind leg touches down before the diagonal front leg. If this time difference is so small that it is not visible to the naked eye and the horse looks well balanced and uphill, it is okay.
If the delay between the hind leg and front leg touching down is so long that you can see it, then it is probably a mistake. Alois Podhajsky calls this “hurried hindquarters” because the hind leg touches down too soon. This would then most likely be associated with a lack of engagement. If the hind leg has to touch down prematurely, it doesn’t have time to reach far underneath the body and would consequently step too short. This could be caused by the rider sitting too heavily and “squashing” the hind legs against the ground. In that case, the solution will be to lighten the seat and to emphasise the upswing of the back so that the horse is able to lift his back and reach farther under the body with his hind legs.
Hurried forehand
When the front leg touches down before the diagonal hind leg, Alois Podhajsky calls it a “hurried forehand”. The horse will be on the forehand when this happens. The excess weight on the horse’s shoulders forces the front legs to touch down too soon. The croup will be lifted and the hind legs will be extended in that case. The flexing and weight bearing phase of the stride is skipped, as the hind legs extend their joints and push as soon as they touch down.
There are horses that find the diagonalization of their footfalls difficult in general. They are mostly gaited horses who tend to do everything in four beats. If the front legs touch down too soon because there is too much weight on the forehand, improving the balance will help the horse to synchronise his diagonal pairs of legs. Diagonal stirrup stepping sequences in the rising or sitting trot also help to restore the diagonal footfall.
The “broken diagonal” footfall pattern can also be observed in the piaffe and passage. The correction is similar to the trot.
Lateral trot
On some very rare occasions I have observed a kind of lateral trot where the left pair of legs touches down together, and the right pair of legs touches down together. Pacing is generally an abnormality of the walk. But if there is a moment of suspension between the lateral pairs touching down, it becomes an abnormality of the trot. I have only seen this in harness racing horses, like American Standardbreds. Just like in the walk the lateralisation of the trot happens when the horse’s back and rib cage are very stiff and braced. When the horse finds his balance and becomes supple and relaxed, the natural footfall pattern will be restored.
Canter
A good quality canter has a 3-beat rhythm with a feeling of UP - 2 - 3, i.e. the lifting of the forehand feels bigger than the downward motion of the forehand:
1st Beat : Outside hind leg is grounded, highest point of the stride
2nd Beat: Main diagonal (inside hind leg + outside front leg) is grounded, the rider’s pelvis is pulled forward
3rd Beat: Inside front leg is grounded, lowest point of the canter stride
Suspension Phase
Unlike the walk and the trot, the canter has an asymmetrical footfall pattern because the inside pair of legs always stays ahead of the outside pair of legs. This requires the horse to bend to the inside, and it creates a certain similarity to the haunches-in position, which is why so many horses canter crookedly with the hindquarters escaping to the inside. There are several deviations from this pattern that can occur for a variety of reasons.
Cross Canter
The cross canter, or disunited canter, as it is sometimes called, is generally the result of the horse’s crookedness. This means that the front legs will be cantering on the left lead while the hind legs are cantering on the right lead, or vice versa.
In practice, I have seen it mostly with the front legs cantering on the true lead and the hind legs cantering in counter canter. The reason for this is usually a stiffness of the inside hind leg. It seems to happen mostly when cantering in the stiffer direction of the horse. In the canter the inside hind leg is the more carrying one and the outside hind leg is the more pushing one because the inside hind leg touches down closer to the center of gravity. If the horse’s inside hind leg is not strong enough or not supple enough to flex and to support the body mass, he will try to counter canter, or he will cross canter. Some horses will change leads behind when they are cantering on a circle or coming into a corner because they are uncomfortable supporting a larger share of the body mass with their inside hind leg. If this tendency is very pronounced, it may be an indication that the hind leg in question is hurting, and that a veterinarian should be consulted to investigate.
If both hind legs are healthy, the solution lies in suppling and strengthening both hind legs so that cantering feels comfortable on both leads.
Good 4-beat canter (Redopp)
The 3-beat canter turns into a 4-beat canter when the main diagonal (inside hind + outside front) doesn’t touch down together any more. There are two types of 4-beat canter, a good one and a bad one. In the good 4-beat canter, the horse is so highly collected that the forehand is lifted high enough off the ground that the inside hind leg touches down before the outside front leg. This is a natural development when you increase the degree of collection. The old masters used to refer to this type of canter as the “school canter” or the “redopp”. Not every horse is able to develop such a high degree of collection.
Although this is a deviation from the normal 3-beat footfall sequence, it is not a fault. On the contrary, it is a sign of good training if a horse has learned to collect himself enough to show this 4-beat canter.
Bad 4-beat canter
In the bad 4-beat canter, the outside front leg touches down before the inside hind leg. This is always a sign that the horse is on the forehand. The canter motion feels bumpy and uncomfortable and is often lacking in impulsion, whereas the good 4-beat canter feels soft and bouncy, with good impulsion.
The 4-beat canter on the forehand is caused by riders who overuse their hands in order to shape the neck and make it “round”, or who try to slow the canter down or to collect the horse by holding or pulling in front. The correction of this fault consists in creating more jump with your legs, then directing the energy upward so that the forehand is lifted higher, and by organising the footfalls through stirrup stepping. For instance, a stepping sequence of Inside Front > Both > Outside Hind can be very effective.
Lateral canter
In a lateral canter the main diagonal dissolves and the lateral pairs of legs touch down closer together than the inside hind and outside front leg. It’s a version of the bad 4-beat canter in some ways because the horse is on the forehand, and the outside front leg touches down before the inside hind leg. The difference between the typical bad 4-beat canter and the lateral canter is that in the 4-beat canter the main diagonal pair is more closely linked than the lateral pairs, whereas in the lateral canter the lateral pairs of legs are more closely synchronised. The lateral canter typically develops when the rider sits very heavily and tries to collect the horse mainly with the reins. This suppresses the back and hind legs, and it stiffens the rib cage.
Gaited horses who pace as one of their natural gaits are more susceptible to a lateral canter than 3-gaited horses.
To correct a lateral canter, you have to supple the back, rib cage, and hindquarters in the walk and trot first. In the canter, you have to create more jump with your lower legs, make room for the back to lift, and purify the footfall sequence through stirrup stepping, very similar to the correction for the 4-beat canter.
Terre-à-terre
When you collect the canter, the natural 3-beat footfall sequence turns into a 4-beat rhythm as the outside front leg touches down after the inside hind leg. If you collect the horse even more, both hind legs will start moving together, followed by the two front legs moving together. The hind legs jump under, then the front legs lift up. It looks a little like a rabbit that is hopping.
When this 2-beat gait is performed in a haunches-in position, the old masters called it a terre-à-terre. It’s a powerful collecting and strengthening exercise for the inside hind leg.
When it is performed on a single track it is called mézair, which is a sequence of short levades. The horse advances slightly on a straight line with each hop.
Just for completeness sake, there is another 2-beat variation of the canter which used to be called “carrière”. It was an extended canter in which the horse was not bent and both hind legs would move together and touch down next to each other. When the hind legs are pushing, the front legs reach forward together and touch down next to each other. When both hind legs touch down next to each other they can push with the maximum power.
Final Observation
When I was young, we had to memorise the footfall sequences of all three gaits. Over the years I observed (thanks to high speed photography and videos) that these footfall patterns are not nearly as absolute and as cut and dried as I had been taught. They seem to be quite fluid, with a direct link to the degree of collection and suppleness. There are some deviations from the footfall sequence that are positive because they are caused by a higher degree of collection. Others are negative because they originate in tension, stiffness, and lack of balance.
When you energise the walk and ask the inside hind leg to lift off sooner, the horse will eventually offer half steps or piaffe steps.
The 3-beat canter develops into the school canter and the terre-à-terre if you collect the horse enough.
These are helpful changes in the footfall sequence that are gymnastically valuable, whereas those deviations from the standard footfall pattern that are caused by stiffness, tension, and lack of balance, are detrimental for the horse’s soundness and well-being.
