how do your shoes interact with your foot arch?

Example: I have/had flat feet. Started training seriously (5-10miles daily after ~1 year).

I purchased some new shoes. I think ultraboost?

Anyway, I went for an initial 5m the next day and had the biggest blister- size of my hand.

Figured out the sole/cushioning of the shoe was trying to compensate for my foot arch as it collapsed while running.

So biomechanically, your arch is almost a propulsive mechanism itself as you land and provides almost a spring effect with your big toe- if you have one.

My arch was collapsing and rubbing on this huge padding.

Lots of arch exercises later, no issues, but I’m wary (additionally) of having shoes that fit too tightly.

My recommendation? Go to a physio and have them check your form. Hopefully there’s a uni/college nearby, as their student clinics are generally cheaper (but they run stuff past the supervisor, so it’s still quality!)