Any books you read on running technique which has the potential to reduce the risk of injuries have a few common elements. Each technique or style of running (i.e. Chi Running, Pose Method, Natural Running) has its own particular elements that sets it aside from the others, however they all state that to run with less effort and fewer injuries a runner should:
1. Land with the foot underneath the body
That means DO NOT land ahead of your body because you overstride, break your momentum and increase impact. When you overstride you also have to power up by re-engaging the back muscle chains to start a new stride. More effort, more muscle tension, more impact, higher risk of running injuries.
If you can see your feet when you run (by looking down with your eyes and head, not by bending your whole body) it’s a sign you are probably overstriding, landing heavily in front of your body.
Bouncing up and down too much can be another sign. Usually, if you land under your General Centre of Mass you won’t bounce, you will move smoothly, almost like gliding.
This will also help reduce the rotational forces in the joints which lead to overuse injuries in the ankles, knees, hips, spine.
2. Lean the body from the ankles
This is an up-right, slightly forward leaning from the ankles, correctly aligned posture. Let gravity do the work instead of using your muscle strength.
3. Strike the ground with a midfoot strike
Another common element is the midfoot strike. If you land under your general centre of mass and use gravity to move forward there is no way you will do a heel strike. You will automatically go into a midfoot-forefoot strike.
That being said make sure you don’t run on your toes. You land on the balls of your feet and then allow the heels to touch the ground slightly. That’s it.
If, when you run, you listen closely you can tell whether you land with the ball of the foot. You will hear a “tap” and then you will feel the heel touching the ground. If you hear a “punding” that’s heavy landing and probably heel striking.
If you think about it pretty much all sports require a midfoot or forefoot body weight distribution: dancing, skiing, martial arts free sparring, even tennis. Look at the footwork in this tennis match, just the first 10 seconds.
4. Pick up the feet
Your feet are like pendulums. A long pendulum will move slower, a shorter one will move faster. So stop shuffling your legs, dragging them behind you, instead pick them up and bend your knee.
5. Aim for optimum cadence
Running cadence is measured by the number of strides per minute that each leg takes. The optimum running cadence is considered to be 85 to 90 strides per minute.
If you do all of the above then you can maintain the optimum cadence.
However you have to build up gradually to this cadence if it’s not your normal. Then you keep that cadence all the time and use the lean and picking up your feet to move faster. In Chi Running you also increase the strides to increase speed. But you move faster because you lean more and relax your legs more not because you are using muscle power. You should not put effort to increase your strides, it will happen as you lean more. But first master the lean.
All fine tips, however there is no way to “let gravity do the work” or “use gravity to move forward” as that defies basic physics. There is no way to gainfully use a downward force in the perpendicular forward direction. Gravity is strictly a cost, the less the better for running economy. If there were a way to use gravity to move forward, people would be less efficient runners on the moon or in weightlessness in space, but that is just not true.