Lean
Introduction: Leaning is the next step in Posture Running. Leaning starts you moving forward and keeps you moving forward. More lean means more speed.
Compare: Leaning is not controversial. Leaning is key with all running techniques. Running tall is not the goal. The goal is a elongating your torso and pointing it in the same direction as your legs. That direction is somewhat forward not straight up.
Do: Lean from your ankle.
Don't: Bend your waist, hunch over with shoulders, run straight up, or sit back on your butt.
Why: it moves your stride behind your body. One of the biggest mistakes of runners is to land on their heal with too much pressure due to their stride starting in front of their body.
How 1: Stand tall, up straight and proud with chest out, shoulders back, chin in, and front of pelvis pulled up a little. Then, start walking slowly with the right posture and lean. Once you have it right, then migrate to a slow jog keeping the posture and lean. Once the slow jog is correct, then jog faster, etc.
How 2: Stand tall, up straight and proud with chest out, shoulders back, chin in, and front of pelvis pulled up a little. Then, go up on your toes and slowly fall forward keeping body from ankle to head fairly straight until you catch yourself from falling by starting your stride. Notice stride is behind you. It is very hard to have much of your stride in front of you if your entire frame from ankle to head is in a line falling forward.
How 3: Some runners have a hard time not bending at the waist. Here are some tips. Video your running from the side to see the bend at the waist. Look at your reflection in a building's window as you run by. Look in a mirror next to a treadmill. Watch your shadow. Try breathing by expanding your belly instead of your chest....can't get much air in your lower lungs if you bend at the waist. Nudge your hips/pelvis forward, or pretend a bungee cord is attached to your belly button and it is pulling you forward. Think leaning tower of Pisa not the Hunchback of Notre Dame.
Imperfect Practice: Run slow or jog with your normal lean, then slowly increase your lean for a few seconds, then slowly return to your normal lean, then slowly lean backwards some. You will be amazed at how the different angles feel so differently. This helps you find how much you should lean.
Feel: If you feel like it takes less effort to run and that you are pounding your heels less, then you are starting to get it right. It may feel like you are leading with your hips.
Story: I started to call this Long then Lean. Posture is making your torso long and in alignment with your legs. Leaning tilts this arrow (from ankles to the arrow head) pointing a little forward. This gets your entire mainframe ready nudge your legs and arms in the right way. Many running form instructors start their teaching with feet, legs and arms. I believe that is not the best approach.