Connecting to Source Means Getting Your Facts Straight

One of the things I’ve been doing while preparing my weekly blog is scrolling through old teaching videos, hoping to spark ideas worth writing about. While watching the clip below, at the 2:02 timestamp, I saw myself say something I’ve repeated countless times while teaching about the foot: 

“Nature, in all its wisdom, has placed 75 to 80 percent of our body’s proprioceptors in the region of the ankle.”

 

“Really?” I thought. “Is that actually true?”

When I began teaching in the late 1970s, checking an anatomical claim like that would have meant pulling textbooks off the shelf or spending an afternoon in a medical library tracking down journal articles.  As I’ve mentioned in other posts, my writing process now includes a research collaboration with ChatGPT and Claude, which allows for fact checking in real time. So when I realized I had no idea where I’d originally heard that factoid about proprioceptors in the feet, I turned to AI to help me research it.

I asked Claude a straightforward question: What percentage of the body’s proprioceptors are located in the foot and ankle? It answered immediately: “Roughly 200,000 of the body’s estimated 250,000 proprioceptors are located in the feet and ankles—about 80%.”

Whew. Apparently I’d remembered correctly.

My relief was short-lived, however, because I did something I’ve learned is absolutely necessary when dealing with a large language model optimized for fluent engagement rather than factual accuracy. I typed: Show me the source for those numbers.

This is when it got pretty crazy. Claude immediately acknowledged there was no published source for the figure and suggested it had produced the statistic because similar claims are commonly repeated in podiatry and yoga literature.

Uh-oh. Could I actually be one of those yoga sources?

After all, I’ve been teaching for nearly fifty years, and thousands of teachers who have studied with me, either in person or online, have heard me state that 75 to 80 percent of our body’s proprioceptors reside in the region of the ankle. Yikes.

I asked Claude to find the podiatry and yoga sources it had referenced. It eventually found a couple of yoga articles repeating similar numbers, but without citations. It couldn’t locate any source for the specific statistic it had confidently given me only minutes earlier. When I pressed further, it acknowledged that even its explanation for where the claim came from wasn’t supported.

By the end of the exchange with Claude, the statistic I've been confidently quoting for decades had completely evaporated.

Apparently, no study exists that has ever counted all the body’s proprioceptors. In fact, there isn’t even universal agreement about what should be counted as a proprioceptor in the first place. Muscle spindles, Golgi tendon organs, joint receptors, and cutaneous mechanoreceptors all contribute to proprioception, but researchers define and classify them differently. Without a total-body count, assigning a percentage to any one region is impossible.

While the 80 percent number turned out to be bogus, the significance of proprioception in the feet certainly isn’t. Their rich sensory structures play a central role in balance, gait, and postural control. Our feet and ankle region never needed an invented statistic to justify their importance.

When I closed my laptop, I found myself thinking less about proprioceptors than about teaching in general. For the first time in my career, I have a practical way to revisit decades of lectures with a question that was once too expensive—in both time and effort—to pursue very often. Instead of accepting a familiar statement because I’ve heard it for years, I can now follow it back to see whether it is actually connected to a genuine source.

Over the coming months, I’ll be working my way through my old material with that inquiry in mind. While I hope I don’t uncover many dramatic mistakes, I do expect to find explanations that can be sharpened, new evidence that has accumulated, and perhaps a few inherited facts that don’t survive the trip back to their source. Rather than diminishing what I’ve taught over the years, if this process gives me the opportunity to replace an old trope with a better explanation, that’s a trade I’ll make every time.

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