Your Achilles tendon, named after the hero of the Trojan War and the greatest of all Greek warriors in Greek mythology, is the strongest tendon in your body.
Your Achilles tendon, which connects the calf muscle to the heel bone, stores energy when your foot lands on the ground, like a tight rubber band when stretched (potential energy), and gives back that energy at push-off (kinetic energy), helping to propel you forward. The better your Achilles tendon is at doing this, the better your running economy.
Next time you go to the zoo, look at the Achilles tendons of jumping mammals, like kangaroos, and sprinting mammals, like cheetahs and other cats. You’ll see they have long, thin Achilles tendons, which act like springs.
The more you can make your Achilles tendons work like springs to do the work of propelling you forward, the less work what has to do? Go ahead and answer; I’ll wait.
Muscles! You are correct!
And the less work your muscles have to do, the less what it costs them?
Oxygen! You are correct again!
And the less oxygen it costs, the more what you are?
Economical! Correct a third time!
Plyometrics, sprinting, bounding up a steep hill, and working on your running technique to optimize your body position and placement of your foot on the ground are great ways to train your Achilles tendons to become better springs and make you a more economical runner.