The “hip complex”—the intricate arrangement of bone, muscle, nerve, and connective tissue that makes up the human hip—is one of the most sophisticated pieces of machinery in nature. As runners, it behooves us to get to know it intimately, because it is the center of athletic power. When the hips don’t function correctly, the body is not capable of dealing with the majority of the resultant torque (from forces produced during walking and running). This is the source of many common running injuries.

Addressing problems with the hip allows the resultant torque to be properly channeled and allocated to the center of gravity, which, during standing, lies squarely within the hips. Therefore, most interventions into the mechanics of the hip complex have to do with maintaining and facilitating the proper flow of mechanical energy throughout the body.

In Donella Meadows’ list of “leverage points” into a system, changes to hip mechanics are characteristic of place # 10:

10: The structure of material stocks and flows.

In this case “materials” refers primarily to the forces that the body generates and interacts with.

It’s important to discuss the hip complex from a few different perspectives. The technical details of how it functions are extremely important. However, even more important is to understand why it operates as it does: If we understand the proper function that it was evolutionarily designed for, and why it is so important to maintain it in correct working order, we’ll be able to divine many of the details of its mechanical function as necessary side-effects of our journey of athletic development.