Anatomy of a Stride
You know from the two earlier posts that the previous two invariables in running -- Pose and Fall -- pretty much happen on their own. This next one, though, requires volition. In a word...
Pull
At the end of the Fall, when vertical ground force has dropped below one body weight, all that's left to do is to get the support foot off the ground and recover the running Pose. This is the one volitional muscle action in running -- simply, bending the knee -- and its timing is everything.
Whether it's just forgotten and left behind, or whether by trying to push off or paw back, a tardy trailing leg tends to precipitate an active landing, that is, having to throw a foot out in front of the body to prolong time on support so that that sluggish leg can catch up. What's more, exaggerated leg-muscles tension interferes with letting go and freely falling with gravity around the support foot.
In any event, when precise timing is degraded, through dulled senses or because neural fatigue has set in -- despite even extreme aerobic and muscular fitness -- concomitant increases in impact, time on support, and biomechanical irregularities begin conspiring to undermine endurance. Endurance, then, can best be described as how well you're able to maintain good technique, rather than by long you're willing to continue slogging out the miles. Skill must last.
Pull Sequence
Like a musician practicing scales and arpeggios, or a martial artist rehearsing katas, a skill set is taught, learned and mastered so that technical fluency can flow, just so. Freely. Indefinitely. Fortunately, instead of a multitude of notes or postures, running requires only that you become proficient at one thing-- releasing the ground on time. That is, just Pull!
Romanov describes...
In order to do this an athlete has to have quite a high level of skill, which includes pulling the foot from the ground coinciding with falling in space and time, and muscle efforts enough to make this pull, but not more than this in order to avoid muscular tension.
* Experience it yourself: Balance in the running Pose, then change support, meaning Pull your support off the ground, and let the other foot find the ground on its own. Easy? Maybe not.
The tendency to reach for the ground before actually lifting the support foot indicates a greater concern with regaining support rather than removing it. See this by recording a couple of your stationary Pulls on video. Step through each, frame by frame, and notice where your feet pass each other. Is it about knee level, or closer to ankle level? (You'll probably see such reaching when stepping through video of your running stride, too.)
You'll probably need to unweight yourself to leave support, and that's okay -- a brisk shoulder shrug is enough. Make sure to Pull before you begin letting the other foot down. Snap crisply into the running Pose with each Pull. Practice on each leg. Then, explore the Pull as you Fall toward a wall (as before).
Here, we return to the concept of Antoine de Saint-Exupery --
A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away.
That's right, less is more. Just pull your foot from the ground.
The End? Nope. The Beginning.
Concluding thoughts, references and links follow in "Running Form: Distilled (Part 4)."