{"id":5411,"date":"2025-10-29T22:53:30","date_gmt":"2025-10-30T02:53:30","guid":{"rendered":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/?p=5411"},"modified":"2025-11-11T13:28:02","modified_gmt":"2025-11-11T17:28:02","slug":"running-and-dancing-what-our-achilles-tendons-can-handle","status":"publish","type":"post","link":"https:\/\/sites.nd.edu\/biomechanics-in-the-wild\/2025\/10\/29\/running-and-dancing-what-our-achilles-tendons-can-handle\/","title":{"rendered":"Running and Dancing: What Our Achilles Tendons Can Handle"},"content":{"rendered":"\n

Imagine trying to withstand a force 12 times your own body weight<\/a>. Sounds impossible, yet that\u2019s what your Achilles tendon (AT) does during something as simple as running. As the strongest tendon in the body, it’s essential for every movement. But the same repetitive motions that strengthen this tendon can also lead to injury. Achilles tendinopathy, pain and swelling along the tendon, is one of the most common overuse injuries in both runners<\/a> and dancers<\/a>. So how can similar motions account for both AT strength and damage?<\/p>\n\n\n\n\n\n\n\n

I\u2019ve struggled with Achilles pain for over ten years. While running still aggravates it, I\u2019ve danced competitively for years without much trouble. By looking at how the Achilles tendon responds to the repetitive impact of running versus the dynamic movement of dance, we can start to understand what might make it strong and what pushes it past its limits.<\/p>\n\n\n\n

About the Achilles<\/h2>\n\n\n
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\"Illustration
Lower leg anatomy with labels edited from Anatomy and Physiology<\/em>. <\/a> <\/figcaption><\/figure>\n<\/div>\n\n\n

Tendons act like springs connecting muscle and bone, storing and releasing energy as we move. The AT<\/a> is especially efficient at this, stretching slightly to cushion each step and then snapping back to help propel us forward. Athletic training often makes the tendon stiffer, meaning it can handle greater forces with quicker responses. But if it becomes too stiff, it can\u2019t absorb shock as well, increasing the risk of small tears or even rupture. Beyond genetics<\/a>, our everyday movements and training styles also shape this delicate balance between power and protection.
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Running versus Dance<\/h2>\n\n\n\n

Let’s look at a study<\/a> that tracked running-related AT injuries in recreational runners like me. Running is high-impact and repetitive, so foot contact and tendon stretch are the same with each stride. Runners who developed Achilles injuries tended to land with their knees and ankles more bent, causing a deeper stretch in the tendon. Over thousands of steps, this can create micro-damage, contributing to stiffness imbalances and chronic tendinopathy. <\/p>\n\n\n

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\"Diagram
Note the greater lower leg angle for runners with AT injury<\/a> compared to the placement of those without. <\/figcaption><\/figure>\n<\/div>\n\n\n

We know running training can strengthen tendons, and we have seen how it can cause damage. So how is dance different? Despite having some high impact, dance involves more multidirectional and variable loading. Another study<\/a> looked at AT stiffnesses in three groups: professional ballet dancers, running-intensive college athletes, and non-running-intensive college athletes. Along the tendon length, dancers and runners had essentially the same stiffness, greater than that of the non-running intensive group. However, across the AT width, the dancers showed more stiffness than even the runners. The authors suggest the stiffness across the width shows the tendon adapting to the varied direction of loading in dance.<\/p>\n\n\n\n

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