@yoppeein r/Sprinting • Recommends
On “Is this a symptom of achilles tendonitis?”
No, this is standard Posterior Tibial Tendon Dysfunction
I know because I just am recovering from it
https://www.google.com/search?q=posterior%20tibial%20tendon&ie=utf-8&oe=utf-8&client=firefox-b-1-m
link to this video