Ok, but how do you get your leg up behind you so it can fall into place beneath you? Sadly, this is even harder to describe. Let me tell you what you don’t use: Your hamstrings, glutes, quads or calves. Let that soak in for a bit. You don’t use leg muscles to lift your leg and you don’t use leg muscles to place your leg beneath you when you land. Its all about body mechanics and posture and physics. Let’s say you are running down the road. Your front torso is falling forward and your legs are moving backwards. If you let your pelvis rotate slightly around your spine (parallel to the ground) then you have one leg beneath you and one leg behind you. Visualize “lifting your ankles”, leaving your foot limp (no toe off) and use your core to rotate your pelvis back and the leg behind you will be pulled up using a combination of core and ligaments. I had been using my hamstrings before, but that is wrong. Trust me you can do this without using your leg muscles at all. Leg muscles are only really used to minimally absorb the impact of each step, and that is all.
Here is another way to look at it. Think of the ground moving underneath you. Your right foot is on the ground and your weight is on your foot. You fall forward and your right foot moves backward relative to your body. As this happens the left foot, which was up in the air behind you starts swinging down on its hinge (knee) so that it can take up support. Your pelvis rotates clockwise about 10 degrees and your leg moves farther and farther behind you (relatively, its not actually that “far”). At this point you “lift” your ankles but really what is happening is leg drifts up behind you because it is on a hinge and your foot has velocity backward but can’t really go back there anymore, so it has to go up right? Combine that with your pelvis rotating the opposite way and a pull from your core muscles and your leg comes off the ground.. only to then be dropped into place to support your next stride.
My Disclaimer: I am not a Chi Running instructor or an expert runner or a coaching professional of any kind. These represent my notes, primarily for my own edification. If they are helpful to you then that is great and I am glad for that, but I don’t guarantee that everything here is absolutely accurate as they are a reflection of my own experience and memory.