19/07/2026
I tilfelle du trengte noe veldig interessant å lese midt i sommerferien 😊✨
"Our anatomy tells the story of what our ancestors needed to do.
Our tissues tell the story of what we do every day."
Why do humans have an iliotibial band when chimpanzees don't? 🙉
The answer isn't because humans are "better designed." 🦵
It's because we solve a different movement problem.
Chimpanzees have a fascia lata that surrounds the thigh, but they don't possess the specialised iliotibial band (ITB) that humans do. In a landmark study, Eng, Arnold, Biewener and Lieberman (J Exp Biology, 2015) showed that the human ITB is a unique evolutionary adaptation that stores 15–20 times more elastic energy per stride than the chimpanzee fascia lata during bipedal walking. In other words, it functions as a biological spring, helping make walking and running more economical.
But here's the part I find even more interesting.
The ITB isn't simply a structure you inherit fully formed. Children are born with a fascia lata, but the distinctive, mechanically specialised iliotibial band develops progressively as the body grows and is repeatedly loaded through walking, running and climbing. Biology expects use. Structure follows function.
This principle isn't unique to the outside of the thigh.
Horse riders often develop marked thickening of the fascia along the medial thigh because repeated loading encourages connective tissues to remodel along the lines of greatest stress. The body doesn't just tolerate load—it adapts to it.
Perhaps that's the real lesson.
Evolution gave us the potential for an iliotibial band.
Movement gives it its form.
When we stop thinking of anatomy as a fixed collection of parts and start seeing it as tissue continually adapting to function, anatomy becomes far more interesting—and far more useful.
Our anatomy tells the story of what our ancestors needed to do.
Our tissues tell the story of what we do every day.
(Photo - author's own taken at BodyWorlds exhibit, Berlin)
