Tag Archives: torque

Running Backwards: a training idea for runners with lateral knee pain.

The exercise of running backwards helps the runner fix quite a few of the most common biomechanical problems, such as lateral knee pain, certain kinds of lower back pain, and plantar fasciitis. It does this by correcting the location of your center of gravity (CoG).

The CoG is importantly related to the body’s “mechanical solution,” the algorithm of muscle contractions that maintains the body erect and stable throughout the course of activity. Because the CoG is defined as the place where there are no forces acting on the body, any shifts or changes in the muscle firings that the body interacts with mechanical energy—any change in the mechanical solution—will necessarily alter the location of the center of gravity.

Strengthening a muscle that was previously too weak to be used in strenuous exercise will change the body’s mechanical solution: for any particular action, employing more muscles instead of less facilitates the body’s movement through space, since the brain is better able to correct for a center of gravity that moves due to change of direction, change of speed, or variable terrain.

Continue reading Running Backwards: a training idea for runners with lateral knee pain.

The “hip complex:” The reference point for the center of gravity.

Most of us know that when we run (or just walk around), our weight should be on our hips. This allows us to move faster and more powerfully, and to prevent injury. It’s also often said that the hips are the “center of gravity.”

skeleton m
The “center of gravity” is represented by the red dot.

All this is completely true. But what does “center of gravity” mean, anyway?

The “center of gravity” is the point in a body around which the resultant torque (or “resultant force“) due to gravity and other sources of mechanical energy vanishes. In other words, all of the forces that are generated by the body, as well as their interactions with the earth’s gravitational field, all get canceled out at the center of gravity.

The resultant force. This isn’t a commonly used term, but it’s one whose implications we should understand if we want to become safe, effective runners.

Continue reading The “hip complex:” The reference point for the center of gravity.