pict. # 1 Cheetah	pict # 2 Dumas
pict. # 1 : The colt is in the lateral phase , both legs on the left are on the ground. The right hind foot will set down next, it's already reaching forward. Then he will lift the left hind leg up , leaving a diagonal pair on the ground. He will be in exactly the same diagonal phase as his mother in the picture.	When the right front foot sets down, the left front will be picked up next, see Dumas in pict. 2, it's a lateral phase again with both right feet on the ground,
pict. 3 Dumas	pict.4 Talento
until the left hind foot sets down and the right hind foot lifts up , see Dumas in pict. 3, below, in the diagonal phase again.	Talento in pict.4 is is in the same phase as Dumas in the picture before, but closer to changing to the next one. He is reaching forward with his right hind and ready to set the left front foot down and lift the right front foot up, which will then put him in exactly the the same lateral phase as the colt in pict. 1.

 

The hooves still set down in the same order, but spend less time on the ground, they get picked earlier in relation to the other ones setting down!
Pic.5 Banjo , walk	Pict. 6 Cheetah, corto
When you compare the two pictures above, you see that at the walk, pict. 5, the left hind foot lifts upafter the right front foot sets down ,	and as the speed increases to a trot speed, pict. 6, the left hind foot is picked up sooner, before the right front foot sets down , changing the support from 3 legs to 2 legs.
In the pictures below the speed has increased further to a faster gait (pict. 7), with more reach and the hind foot getting picked up sooner than in the corto/ slow single-foot, it is already swinging forward. (fast corto/ medium singlefoot)	Pict.8 shows a fast Largo/ true single -foot (speed of canter or gallop). Compare with thefast corto/ medium single-foot: the left front is still on the ground, the right rear is just setting down, and the diagonal pair is still way up in the air, because they were picked up sooner!
Pict. 7 Dumas, fast corto	Pict. 8 true single foot
Many pictures of gaited horses show the phase of movement as in pict. 8, even though most horses would have the right rear on the ground before the other two are picked up like that. Pict. 8 shows Rowdy's Lil'Rascal, performing what many call the "true" single- foot gait with only one foot on the ground, at a very fast speed. All the horses shown on this page are registered with the North American Single Footing Association (NASHA), to get registered they have to show the ability to stay in gait through a good range of speed, but not necessarily the ability to gait faster than trot speed. It is not known whether the name: "single- footing" originates because each foot is lifted and set down "single" as compared to " in unison" with another foot, as in a trot, ----or because a single foot is left on the ground supporting the horse. The horses shown, except Rascal, are also registered with the Paso Fino Horse Association, where the gaits they would be: walk, corto, fast corto and largo, ------- instead of: walk, slow, medium and true single-foot. Rascal is a NASHA horse owned by David Stanley.
WHAT YOU FEEL: Because the horse shifts his body smoothly forward and stays evenly supported by the independently moving legs underneath, the rider feels neither up and down, nor sideways moves of the back, nor the impact of hooves setting down. When the horse moves froma fast walk to slow gait, you can feel a very slight "change of gears", as his hooves touch down with more spring and lift up quicker. The horse becomes a bit taller. As the speed increases, the horse gets lower to the ground again, because his legs reach further. When he changes to one - leg support (very fast gait), a "change of gears" can be felt slightly, the front end comes up and the rider can feel incredible power under him.
When riding the so called " running gaits", like the gaits of the Paso Fino, Single -Footing Horse and Islandic Horse, the rider feels like sitting in a totally quiet center with the legs rotating very fast, like a tap dancer moves his feet while holding his upper body still, and the horse seems to be bursting with energy.	Other breeds specialize in so called "marching" or "plantation" gaits, like the Tennessee Walker or five gaited American saddle horse, where the rider sits in a quiet center but feels the horse pushing forward with very long and animated strides, as if the horse was gliding along with big, powerful strides on roller skates. This type of gait was preferred for riding on plantations and requires fairly smooth and level ground to be performed with any speed, because the horse slides his hind feet under himself. Tennessee Walkers have to develop a good deal of head nod to reach their potential when doing the running walk.
Most gaited horses depend on a certain amount of help from their rider to take up the right posture and create enough restrained energy for finding their power, and to concentrate enough to find the fast rhytm of their gaits. Imagine organizing 4 legs to move out of each other's way, balance the horse's weight plus a rider, and doing all of this at fast speeds! Moving the legs in pairs, like a trotting or cantering horse does, and letting the ground fly by while having all feet in the air, is uncomfortable to ride, but much simpler in terms of coordination for the horse. Horses with marching gaits have to really reach and often slide their back feet past the tracks of the front feet. None of this is possible for a horse that is distracted, whinnying, sluggish, slouching, fighting the bit, turning his head to look at things, leaning in turns, carrying his weight on his front legs, etc. But after proper training the horse can gait nicely in a relaxed fashion on a loose rein, as long as he moves down the trail like it was a railroad track, using good posture and paying attention!
Note: To perform the fastest versions of the running gaits, with only one hoof on the ground at a time, the horse has to be well conditioned and trained, the ground has to be quite smooth and level, and it has to have a lot of nartural ability. Only some horses from certain breeds have the ability and are trained well enough to achieve racing speed! It's not something the horse will do very often on it's own in the pasture, it will canter or gallop instead, because it takes a lot less concentration. The gait should stay square without drifting toward pace or trot. Paso Fino or NASHA speed gaiters are known to briefly get up to 20 miles per hour or more in square gait, moving with up to 10 beats per second!!!!! BUT: IF THE HORSE SHIFTS HIS FAST GAIT FROM SQUARE A BIT TOWARDS TROT, CALLED TROCHA, IT CAN BE PERFORMED BETTER ON UNEVEN GROUND, TAKES LESS ENERGY AND IS STILL VERY COMFORTABLE AND FAST TO RIDE. The diagonal phase is longer, which supports the horse in a more balanced fashion. As long as the there is no phase of suspension and the feet set down independently, the difference can hardly be felt. Also compare GAIT with TROT in the pict. 9 (below), showing a gaited horse and a cow moving in sync! Most gaited horses have genes for TROTTING and also for PACING. This gene does not fall under the Mendell law of dominance, where only one or the other can be present. It belongs to the group of accumalitive genes, so each horse will have a different concentration of trotting and pacing genes, producing the gaits typical for each breed. ---They also have a different strength of GAIT MODIFIERS, that allow them to speed up the sequence of the walk a whole lot, without breaking into a two beat (trot or pace) or into a 3 beat (canter). .Each breed has 2 or 3 speeds (with different names and different support patterns, with or without suspension, with a different style of execution) for their gait. When you add up all the variations of the basic walk sequence, from even to uneven gaits, with suspension or without, slow or fast steps, short or long strides, much lift of the legs or low gliding movement, ------ you can see how the many, many different gaits of gaited horses have evolved!

THE TROT

pict. 9 Corto / single-foot (horse) in sync with a cow at a trot. (Pencil enhanced video-still (it was very blurry and faded) of myself riding Dumas at at a cattle working clinic)

Both move along at the same speed and length of stride. The horse is making  4 beats because each hoof lands independently, and the cow makesakes only 2 beats because the diagonal pair of legs move together. Both animals started their stride by pushing off the left hind foot and reaching forward with the right hind foot. The cow moved her left front leg in sync with the right hind leg and is supported by the diagonal pair of legs, while the horse moved it's legs independent and is in the lateral phase, supported by his left legs. The cow will soon hop up to get the right front foot, and with it the left hind foot, out of the way, and then change her support to the other diagonal pair. The horse has his right hind foot already touching down, next the left rear will lift up, and it will be supported by the same diagonal as the one the cow is changing to: Left front and right rear. They will both complete their stride in the same distance, at the same speed, the cow with two beats and the horse with 4 beats. While the cow had to hop up to clear the ground, the horse glided from one foot to the other in perfect balance, effortless.

Basics of trot: Whenthe horse (or other animal) trots, it moves a diagonal pair of legs forward together, so when one hind leg pushes off, the other hind leg and the opposite front leg both swing forward to support the body mass. But before the hind leg can touch down, the front foot on that side has to get out of the way ( rule #1), and with it the opposite hind leg, since they move in unison. Result: All 4 legs are off the ground for a moment, called suspension. There is a phase of suspension twice in each stride ( a stride is completed when all 4 feet have been picked up and set down), just before one pair of legs sets down. The time elapsed between each pair setting down is exactly the same, making it EVEN, and because two feet set down together, only 2 BEATScan be heard. The trot is an even, diagonal 2 beat. What you see in a photo: You always see the diagonal pair moving exactly together, during the suspension phase you see all four feet off the ground, one diagonal reaching forward, ready to touch down, the other swinging back, they have just left the ground. What you feel: The horse needs to push his whole body not just strongly forward but also up, because gravity will pull him down some, when all feet are off the ground. There is a big up and down movement, with a considerable forward thrust, througho the whole back, but also a separate movement of the saddle. With the diagonal pair moving together, the back part of the saddle dips down on one side while the shoulder tips the front part of the saddle on that side up, while at the next moment the same happens on the other side. It takes practise to be able to sit through all the movements of the trotting horse without bouncing. When two hooves land together after the whole body was suspended, there is often a considerable jarring as well.

THE PACE:

The horse moves 2 legs together and sets them down together in a 2 BEAT, but this time on the same side of his body, a LATERAL movement.(like a camel).
The horse can pace either with or without suspension, depending on speed. The horse does not have to worry about getting the front foot out of the way of a landing hind foot. The timing between the pairs touching the ground is EVEN.
The pace is an even, lateral 2 beat.
What you see in a photo: Two legs on the same side reaching forward, the other two swinging back.
A true pace is not accepted under saddle by any of the gaited breed associations, but popular in harness racing.
The "FLYING PACE" of the icelandic horse is the closest to a true pace, but a photo proves that the hind foot sets down before the front foot on that side, making it a 4 beat gait.
What you feel: A true pace with suspension would be awful to ride, like a trot only with a sideways sway.
But when the landing of the hooves is even a little bit spaced, making it a STEPPING PACE, it becomes a nice gait to ride.

Even a very small break in any gait that looks like a two- beat gait, be it trot or pace, make it a whole lot smoother to ride! Anybody can feel the difference with great relief, but it takes a photo to prove it to the observer.
Any time a horse is moving in a two beat gait under saddle, with two hooves setting down together, he is not "in gait"!

Uneven gaits: (the amount of time between the landing of each hoof, or pair of hooves, is not the same, the beat is uneven.)
THE CANTER AND GALLOP:

The canter is a 3 BEAT. It includes elements of the trot, like a DIAGONAL pair of legs landing together, and has one phase of SUSPENSION (no foot on the ground) in each stride.
In the canter the horse is offset.
Picture four people rowing a boat in pairs, with either the two on the right, or the two on the left side of the boat having their seats ahead of their partners.
Footfall (right lead): left rear, right rear and left front together, right front, suspension.
(left lead) : right rear, left rear and right front together, left front, suspension.
When the horse is on the left lead, the left legs reach further, and vice versa.
The horse is best supported in a turn when cantering on the same lead as the direction he turns to. (right turn -right lead) This is easy to understand when you picture the leading hind leg well forward under his body and the opposite front leg on the ground at the same time, leaving the horse well supported while the leading front leg can reach out to the side to start the turn.
pict. 10 
The horse is well supported by the leading hind leg (right), and opposite front leg in a right turn. In this phase he has three legs on the ground and can reach with his right front to the right to turn. 

Imagine how much harder it would be to turn left.

Compare this picture with the drawing taken from a video still above, pict.9 .
Even though there is so much difference in rythm between an even 4 beat gait and a canter, because the canter has an uneven footfall, the leg support at that moment is almost identical. But in the canter, in Pict. 10, the horse would dip down on his right front leg in the next moment, while all 3 other legs would lift off, vaulting the horse's body over the leading front leg, before that lifts off, also, for the phase of suspension with all feet in the air.  
Note: Gaited horses often have a very short or non existent suspension phase in their canter.  In order for the horse to be a suitbale mount for fast cattle work or ghymkhana, he needs to have a strong enough suspension in his canter or gallop that he can switch leads to make tight turns at speed.  Any horse can stop and roll back and jump out again, but to gallop a tight circle as needed for turning a cow, barrel racing or pole bending, he needs a decent canter.  It still feels smoother than on non gaited horses, but the ones that lack a clearly defined canter movement have a disadvantage. 

Horses that are ridden at the canter need to learn to use both leads, to avoid fatigue of the side he leads with.  This can be challenging to the rider, especially when you have to coax your horse to use the other lead on trail rides. The horse usually takes the inside lead if the sees a turn in the trail coming (left for left turn), or the lead towards the uphill side of a road or trail.
If you can teach him to move his hind quarters right or left while his front stays lined out, he will easily take the lead on that side.
It also helps to keep your weight a bit heavier in the stirrup opposite the side you want him to lead with.

The canter is an UNEVEN 3 BEAT. 1-2-3 pause. The amount of time between each foot landing is different, typically beat 1 and 2 are very close, then it takes just a bit longer before beat 3.
After the suspension, the horse is supported briefly by one hind leg (left in the picture)--beat #1, then by three legs when the diagonal pair lands (right rear and left front)--beat #2, then still by three when the leading (right) front leg lands-- beat #3, and the left hind leg lifts up, then by one (the leading front leg) when the diagonal pair lifts up (right rear and left front), followed by none( suspension).

What you feel: Cantering is a bit smoother than a trot. While a trot moves the four corners of the back diagonally up and down one corner at a time, at a canter the back stays level from right to left and just moves up and down in the front and back. The rider's leg and shoulder on the side that the horse is leading with, tends to swing forward more. If the horse breaks into a gallop the up and down movement becomes less.

Gaited horses canter very smooth!
Instead of moving the diagonal pair together to create the "proper" 3 beat canter, many gaited horses do their cantering in an uneven 4 beat canter .
UNEVEN 4 BEAT CANTER OR GALLOP:
As in a true, fast gallop, they split the landing of the diagonal pair up, so you hear: 1-2/3-4 and then a brief pause. Beat two and three are very close together.
Look closely at the pict. 10 above. You can see that the right hind leg is just setting down, but the left front has set down a bit earlier, instead of those two landing together. Just like a gallop seems much smoother than a canter, a 4 beat canter is smooth, because the legs all set down independently. Another reason for the famous smoothness of gaited horse's canter is the fact that the phase of suspension is a lot shorter.
For many gaited breeds a very slow 4 beat canter, executed with a lot of style and with elevated shoulders, is a valued and "proper" gait in shows, also called a "rocking horse" canter.

THE GALLOP:
In the gallop the diagonal pair lands separate, making it an UNEVEN 4 BEAT as described above under UNEVEN 4 BEAT CANTER.

THINGS THAT CAN GO WRONG:

Pacing Canter:
Some gaited horses use a pacing canter instead of the regularl 4 beat canter, where the LATERAL pair of legs land very closely together (instead of the diagonal pair) : 1 / 2 - 3 / 4, then a brief pause. This gait is dangerous to ride over rough ground or through turns, as the horse is totally unbalanced when all feet are in the air briefly, and then for example the left feet set down in a right turn.
Of course this is also true for any fast PACE or STEPPING PACE, the Icelandics for example perform their flying pace best on level ground, going straight. Gaits that use lateral support are not suitable for sharp turns at speed.

Skipping or hitching:
The horse takes too short a stride with the front legs, so he can't  keep his pattern of footfall.  The horse goes to a pacey canter for a few steps, and then the front foot tries to land before the hind foot does on the same side, getting seriously in the way of that reaching hind foot!  
The horse suspends a stride with his hind leg to the point of  skipping a step, switching which hind leg lands next to get the foot fall in order again and avoid stepping onto his front leg.
It feels awful, and often upsets the horse visibly.
This often happens in ealry training when shifting from a canter down to gait by pulling on the reins, without first helping the horse to shift his weight back.
It can also happen if you trim the front feet but didn't get around to trim the back feet also.
Some horses do this if they are very tense, excited, or fighting the bit.
When hitching at a 4 beat canter, the horse ends up with the opposite lead in the back (cross firing),and the saddle slapps your bottom so hard you think the horse is trying to buck.
The horse might have his head up or down, and usually gets very upset.
If the horse canters relaxed, he can switch leads in the back very smoothly, whether it's to change from a cross fire to regular canter or if he drops his lead because he becomes overbent in a turn.