The Achilles Tendon—Not Just a Legend!
The Achilles Heel is not just an ancient legend or a metaphor for vulnerability. Achilles tendonitis is literally a pain in the heel.
The best starting point in discussing this injury is with the affected tissue:
Your Achilles tendon.
Regarding connective tissues in your body, the two you’re most likely to be familiar with are tendons and ligaments. This often raises the question—what’s the difference between a tendon and ligament?
Whereas both tissues are anchored to bones on one end, the distinction is what’s connected on the other side. If it’s another bone, then we’re talking about ligaments. If the tissue connects a bone to a muscle, however, it’s a tendon.
Your body has approximately 640 muscles, along with thousands of tendons connecting them to various bones in your skeletal system. Your body moves when muscles either contract or expand, thereby pulling or pushing (respectively) tendons connected to bones.
(As we discuss the Achilles tendon specifically in just a moment, you’ll see a great example of how this works.)
Out of all those tendons in your musculoskeletal system, your Achilles tendons are the strongest and largest. In fact, these particular tendons are uniquely structured. Whereas other tendons have fibers that line up side-by-side—like bristles on a broom—these ones are wrapped around like a heavy-duty cable.
Of course, an Achilles needs to be quite strong on account of the role it has in allowing a foot to move either up or down!
See, the Achilles tendon is anchored on one end to the bottom of your calf muscle, and the calcaneus (heel bone) on the other. When your calf muscle contracts, it pulls on the heel bone and your foot points downward. As you might expect, elongating the calf muscle push the heel bone and raises your foot.
Now think about how your foot moves as you take a step. When it lands, your toes are raised, right? But then the rest of your foot comes down during the ground portion of the step, culminating in a final push from the toes as you contract your calf muscle.
In the back of your heel and lower leg, the Achilles tendon is activated pretty much the entire time.