If the trainer is good they don't do reining moves at any type of speed until their 3yr old year. At 2 the horse is trained to be a western pleasure horse. They are given the basics of the movements. IE. turn on the haunches, circles, a good whoa, and leads. They also work on leg yeilds and side passes, shoulder in/out, hip in/out.
The real hard core training comes at 3 when they are asked to spin correctly and faster. They are then also trained to lead change and the stop is more refined. It isn't until most everything else is set up that they start asking for sliding stops and they don't do them all the time.