I've used these shoes for recumbent bike, Zumba and circuit training. The arch support is great, the ball of my foot doesn't get numb on the bike and the heel doesn't slip--even with lunges. This is my favorite workout shoe. However, I tried to use the circle on the bottom of the shoe for spin turns in Zumba on wood floor and on tile--no dice. However, as comfortable as these are with the arch support and forefoot cushioning, I'd much rather have that than a shoe that spins around. I have a pair of Bloch's that spin with no problem...and get tendonitis every time I use them! I'm getting rid of the Bloch's and getting another pair of these! I wear an 8.5 in sandals, slides or other sockless shoes. In workout shoes, I generally go up a half size or a full size to accommodate plush socks. These I went up to 9.5 and it's comfortable, but could probably go with a 9.0 on the next pair.