Someone posted that it was physically impossible for many gaited breeds to trot. This is actually not true. They all have the means and ability to trot (and canter, as a side note), but they are not trained or bred to do so. They are conformationally the same as a trotting horse. Gaiting in a genetically ingrained behavior. It is simply natural to them to gait.
Some will trot when they're getting lazy and are not made to stay in a gait. Some horses simply hate to trot and will gait constantly, even at liberty.
I have never riden a gaited horse that trots when they are getting lazy. Most here are racking horses & they never trot! Some will PACE when they are getting laxy, but never trot!!!
Around here there are many gaited horses. They are bred specially to gait, not trot. When the foals are born, the breeder will say..."look at those crooked legs! That's a good one!"
Conformationally, they are different. The hind legs are set back more & wobble in the hocks. The breeders LOVE IT if they see the hocks rolling around! That means the horse will rack very well...
Saddlebreds can be 3 or 5 gaited, with trot in both types. However, many racking horses can not trot. It doesn't happen, from the time they are born! I would love to see one of you try to get them to trot!
The gait they do looks like a pace, but is a little different, more four beat. The Tennessee Walkers have a "head-bobbin" gait where it looks like they are troting in front but walking in the back. There is little to no suspension which is why it is so smooth to ride. The "big Lick" walk on the padded shoes is very weird to ride, I can't really describe it, but if you get the opportunity to try, DO IT!!
I have riden many of these horses & even owned a few. Also I had a pony that was 1/2 racking horse & 1/2 shetland. It is very common in the south to use a shetland pony for a teasing stallion because the thinking is that they are not big enough to get the mare pg, however, every once in a while the shetland convinces the mare to cooperate...the result is a pony like mine, walk, rack, trot & canter.
If you want to ride some, make a trip to Tennessee & go on some rides. The rider doesn't post except on Saddlebreds & Park Morgans & Arabians.
The paso's do a shorter stepping movement...it looks like they are going over hot sand
(ouch, ouch, ouch, ouch!) Also I see a lot of them paddling in the front.
Around here, riders get upset if there are Saddlebreds & Racking horses in the same class because the movement of the two is soooooooooo different!