Just had my first visit in years to a podiatrist- apparently I have hyper mobile FEET. He bent my big toe up and waggled my heels and it’s all a bit loose. Could explain my occasional Bambi-esque wobbliness and aching feet muscles which have to work hard to keep me flat and securely moving forward. But he was supportive of jogging - in moderation and on the springy turf of the downs (watching for rabbit holes one of which ended his own marathon running) and approved of my flexible calves and hamstrings. He fixed my ingrowing toenail and spotted a verruca.
I have new found admiration for podiatry and foot muscles.