The anatomy of running

In one step alone, over 200 muscles are activated in order to move the body up and forward. As those steps pick up in pace, the greater and greater force ends up being generated onto the ground.

To counter and support that force, over a dozen muscle groups have to not only engage but also collaborate to continue the run cycle. “Muscles are typically connected to tendons, which are connected to bones. And in that way, they’re able to move the skeleton in a distinct pattern that allows people to run,” explains Alena Grabowski, a research scientist and associate professor of integrative physiology at the University of Colorado Boulder. Grabowski’s work takes a closer look at the wonder in how people move and the energy that’s required for walking, jumping, and running.

While running can seem simple in that it’s just a cycle of movement, each muscle group needs to collaborate with other muscle groups so as to counter both the horizontal and vertical forces. On the heel strike of a run, studies have shown that the vertical impact can equate to around four times the body weight. For example, if a runner weighs 200 lb, up to around 800 pounds of pressure can be exerted onto the body. Various muscles found in the calves step up to the plate and act as a shock absorber for some of that impact and propel the body back up for the next step.

And while the legs are acting as the main motors, they are grounded and balanced by the hip flexors and glutes. Hip flexors are what makes this muscle engagement even possible; without them, humans would be unable to raise the knee which is critical to running, even walking.

But the really remarkable thing about the human body and its muscles is that they are always shifting and adapting to take on all kinds of activities. This adaptability shines and is celebrated through a variety of different body types. In running, for example, the biomechanics evolve in response to the use of prosthetics. “The biomechanics for running for me obviously starts with trying to be balanced,” shares Zach Friedley, a professional trail runner and On athlete. “Because I run with the blade my balance is super important to make sure I feel sturdy; without balance, I wouldn’t be able to run,” adds Friedley.

Inspired by his own experience in running with a prosthetic, Zach founded the Mendocino Movement Project, a non-profit organization for athletes of all abilities. “I want to grow this sport of trail running to where there’s more of us out there, because I’m not the only person running trails. Fifteen percent of the world’s population is disabled- that’s a billion people that could have an opportunity to come out and enjoy the trails,” exudes Friedley.

The human body in motion is a resilient complex machine.

Whether a runner is training on the tracks for the Olympics or running on the trails for a hobby, the human body in motion is a resilient complex machine that relies on more than just the feet. That’s clear from also talking to the runners in the video above. “I love running because I feel like I’m in tune with every muscle in my body,” notes Han Na Shin, an activist who is training for her first half marathon. “When I run, it’s not just an exercise or a feeling. It’s my inner spirit,” shares Tuni Ntuve, a dancer who has been running every day since she was seven years old. “I feel powerful when I run,” exclaims Mary Johnson, a law student who competes in races with a prosthetic.

Every runner, no matter their background or body type can explore what running means to their practice. After all, a runner’s body is a body that runs.