What would “fundamentals” of movement be? First things first, how do we even decide if something is fundamental?

Chronological Fallacy

There is often a “chronological fallacy” deciding that what is fundamental is what came prior. For example, the motor control challenges of infancy are fundamental for development at a particular stage in life. Some people, taking those challenges for absolute fundamentals, continue to work on those in adulthood, believing that those are fundamental to movement, broadly.

An analogy to clarify the fallacy: imagine you want to grasp the fundamentals of “navigating boats”. There is a period of time in which what is fundamental is knowledge and skills surrounding building of boat, prior to the existence of the boat. But once the boat is built, the scaffold removed… that skillset is no longer so fundamental. Now, navigation becomes the real fundamental thing. The area of “building of boats” is fundamental only through that one single connection, that moment that it leads us to navigation.

Once we have passed a certain stage, what was fundamental for development is no longer fundamental.

That doesn’t really tell us how to decide what is fundamental, but it does tells us how NOT to decide – by arguing to what arises first.

Do the same thing, but differently

To identify what IS fundamental, it is maybe helpful to look at another situation: a bipedal human coming across a vertical rock wall.

If you practiced bipedal locomotion with your mind only ever thinking in a specific manner (looking to improve bipedalism, at the cost of anything else, without looking to find broader more universal principles because you have decided you are a bipedal locomotion specialist), you would be lost when confronting the vertical rock face.

But if you practiced that exact same bipedal locomotion, only with an eye for general principles, when it came time to work with the rock you would find yourself somewhat better prepared.

So it was in practicing bipedal locomotion in a generalist manner that you came upon something that was relatively more fundamental, than if you practiced in a specialists manner. That thing might have been contralateral weight shifts, or the discovery of the general principle of balance (center of mass over base of support), or in how to optimize tendons for absorbing and releasing energy in locomotion…

Therein lies a hint of the criterion for fundamental-ness.