The History of Human Movement
Chapter One of Healthy Movements for Human Animals
Note: This is chapter one in my new serialized book Healthy Movements for Human Animals. It got a bit long, so I decided to split it into two chapters. The follow-up will arrive next week. The previous chapter (The Introduction) is here.
In the Introduction, we discussed the idea that the healthiest movements for human animals are most likely those movements that the body is well-adapted to perform. To understand the process of adaptation over time, this chapter will examine the evolutionary history that shaped our bodies over millions of years.
Before doing so, I can’t resist sharing some of my favorite quotes about the value of learning history:
“People are trapped in history and history is trapped in them.” - James Baldwin, author
“If you don't know history, you are a leaf that doesn't know it is part of a tree.” - Michael Crichton, author
“Everything is the way it is because it got that way.” - D’Arcy Wentworth Thompson, biologist.
“Nothing in biology makes sense except in light of evolution.” - Theodosius Dobzhansky, biologist.
Now that we are all suitably impressed with the wisdom and solemnity of addressing this topic, let’s examine the history of human movement. It's about 400 million years long, so I promise I will stick to the highlights. Why go back so far? When you zoom out, you can see patterns that are invisible when you look up close.
Evolutionary History
The basic skeletal layout for human beings - head at one end, tail on the other, and a stack of flexible vertebrae and ribs connecting them - originated with fish in the ocean about 525 million years ago. The most important movement for fish is side-bending of the spine in an oscillating wave-like pattern. This moves the tail left and right and powers the fish forward through water. The fins on the sides don’t provide any forward propulsion, they are just there for steering.
On the ground
The fins started contributing to forward movement about 350 million years ago, when the first amphibians started “walking” in shallow water, and then a few feet onto land. They used their fins as primitive limbs to elevate their bellies just a little bit from the ground, as if they were doing a mini-pushup.
Although their limbs were primitive, they created a basic blueprint which is now shared by every four-limbed animal (tetrapod) on earth: one upper bone connecting to two middle bones, connecting to many small bones, connecting to five rays or digits. This fundamental pattern remains evident in creatures as diverse as bats, whales, horses, and humans, though modified for different purposes.
Reptiles evolved from the amphibians, and they walked over land using the same side-bending spinal movement patterns as fish. Picture how an alligator walks: belly low to the ground, limbs splayed out the sides, with each forward step assisted by a sidewinding movement of the spine.
A critical shift occurred with the evolution of mammals. Their limbs moved directly under the body, supporting weight more efficiently. With bellies lifted from the ground, limbs could reach more directly forward and back instead of out to the sides.
The spine could now assist locomotion more through flexion and extension (arching and rounding) rather than side-bending. This more powerful pattern is visible in a cheetah's sprint—its spine alternately arches and rounds as legs surge forward and back.
Interestingly, the shift to a flexion/extension based pattern of spinal movement in