There are a large number of videos on the web showing various aspects of pose running. This may be the best introductory one.
Further explanation can be found here, though I don’t think they really have it right. As best I can tell, “pose running” comprises short strides, decreased use of hip flexors, increased conscious use of hamstrings, and slight forward lean, with slightly flexed knee during forefoot strike. The talk about pose runners being propelled by gravity is pretty much nonsense, like a perpetual motion machine. I guess they make some money selling a belt with rubber bands that work with your hamstrings to flex the knees.
But there is something real here, and I suspect it might have to do with the “braking” action inherent in conventional knee drive/heel strike running. That is, if the impact occurs with the foot out in front of the body, then that impact tends to reduce speed. In contrast, during pose running, the impact occurs with the foot under the body. This would tend not to slow the runner, and would also decrease the impact somewhat.
I think I get it, and am going to give it a try.
UPDATE: after a couple of sessions, I think it may have some merit. But making the transition from heel strike to forefoot strike has given me some sore calves. I would recommend making a gradual transition.
I am not so sure that the emphasis on high rear kick is helpful…anything done to further elevate the foot after it leaves the ground is wasted energy.