The runningwalk is exactly what it sounds like. The hoof-fall pattern is identical to the walk, four beat and even (neither lateral nor diagonal). The Tennessee Walking Horse is of course the breed best known for this gait, but many gaited horses have this “middle” gait. The Tennessee Walking Horse tends to have gaits on the lateral end of the spectrum, both because of the rack (being an even footfall but lateral in weightbearing), and because of the emphasis on overstride, where being a hair to the lateral helps in preventing interference. These middle gaits can absolutely be achieved without any equipment or shoes. The horse in a runningwalk should have a fairly level back, and as such it much kinder on the back than any of the lateral gaits. However, it can be very straining on the lower limb. It is a difficult gait to collect, as most horses will either fall to the lateral or break to the flat walk.
Keep asking for your horse to extend the walk. Some horses are so smooth you may not even notice the change of gears at first. Get to know the feeling of the transition, even though our goal is for it to be nearly imperceptible. If you can feel the moment the horse goes into gait, you will be able to ask for the gait more reliably. You might feel as if your horse’s back suddenly tilts, as they work to get under themselves, and you suddenly have more power, more “go”. A moment before, they were laboring to extend their walk, and now they have plenty to give.