Hi, I have been having the problem of keeping my heels down when I ride and keeping the stirrup at the balls of my feet. Whenever I'm posting, and I'm doing a good job of keeping my heels down, the stirrup will slide down my foot so that it's at my heel. I've tried kids stirrups, but they're too small, since I have slightly wide feet. Any advice? If it makes a difference, I do dressage.