What really causes more atrophy of the fat pad cushion under the ball the foot in runners…inactivity, or too much activity?
Well, that’s what we are talking about today on the Doc On the Run Podcast!
I got this great question from the Injured Runners Aid Station. It came from a marathon runner who had been suffering with aching pain in the ball of the foot. She had been doing some research and she became worried that she was having forefoot discomfort mostly because she was losing the natural cushioning between the bones and the feet when standing on the ground underneath her.
One doctor had diagnosed her with a Morton’s neuroma.
She got a second opinion, but the next doctor diagnosed her with a plantar plate sprain.
The third doctor said she was having metatarsalgia because of “plantar fat pad atrophy.”
The third opinion didn’t sit well with her. Because in her view, as a highly trained athlete, had always viewed “atrophy” as degeneration due to laziness, lack of use, or simple wasting away due to inactivity. To her “atrophy” was as insulting as the term “weakness.”
In some sense that perception or definition holds true. Is also easy to understand how athletes jump to the conclusion that atrophy of any tissue is caused by sitting still.
If you spend years in the gym doing squats with heavy weights you will eventually build well-developed quadriceps muscles. But you can only get monster quads through hard work, dedication and diligent effort.
And even if you work on them for years, once you stop working out those big muscles will eventually atrophy and start to wither away.
But muscle atrophy and fat atrophy do not work the same way.
Muscles wither away only through neglect, or the inability to repeatedly fire those muscles to keep them big and growing. If muscle isn’t growing, it’s probably shrinking. That is typical of muscular atrophy.
Fat pad atrophy happens for the exact opposite reason. You wear away the fat pad and it gradually becomes thinner.
Here are a couple of well-known examples better documented in the medical literature:
Diabetic patients may be the best example of how fat pad atrophy can happen.
A diabetic patient develops an ulceration in the skin. It is effectively a hole in the skin that started as a blister. But the diabetic patient does not feel it, so they literally wear a hole right through the skin. Since it doesn’t hurt, they continue walking. In the same way the pressure and friction wore a hole in the skin, it starts to wear away, abrade and reduce the thickness of the fat cushioning in that open wound.
A number of published studies suggested the fat pad atrophy is not caused by dis-use but is caused through aging or wear and tear over many years of standing, weight-bearing, and the pressure and friction from walking.
When the fat pad cushion between the bones and the skin under the heel or the ball of the foot gets thinner, doctors call it “atrophy.” But don’t take it as an insult.
If you get diagnosed with “fat pad atrophy” and you are an otherwise healthy, non-diabetic runner in the prime of life, don’t be worried that any fat pad atrophy was caused by inactivity, resting while you were recovering from a running injury, or even from wearing a fracture walking boot or cast.
Those things cause a different kind of atrophy altogether.
If you like this episode, please send it to runner or you think might need to hear it.
If you have pain in the ball of the foot you might want to check out the Plantar Plate Master class for runners. It’s free, and you can get it at www.docontherun.com/plantarplatemasterclass.
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