This is why I don't go to the gym anymore. I was born with a condition that meant my arches fell as a child. After years of pain and expensive shoes I found a physio that really helped me. She advised me to build up the muscles in my feet by exercising barefooted. I have done it for yesrs now and no longer have an ache or pain.
I am lucky to live in the country where I can jog around a field with no shoes on but before when I attended a gym and used the treadmill with clean socks, the looks I got
. People can be so bloody judgmental. Believe it or not, it's actually healthier to exercise barefooted. It's better for your feet. We are a society obsessed with germs and cleanliness and view everyone as germ banks. Please just consider this.
Lots of sports, martial arts in particular, involve people exercising bare footed, my children are doing it years now and have never had an issue with infections. Just my tuppence worth, I don't know trishas trainer but perhaps she's seen benefits to barefoot training with her clients.