When you point your toes forward, how is your foot oriented in the stirrup and is there even weight across the ball of your foot, or lots of weight on the outside and almost none on the inside?
For me, it usually felt like weight wasn’t going straight through my ankle and yeah all on the outside of the ball of my foot. I tried the old offset angled stirrups once but they were too much. It’s not perfect now by any stretch but my feet aren’t sticking out weird nearly as often as they used to. Basically how my feet attach hasn’t changed but alignment from the hip makes everything below it lay flatter.
I love to jam my heels down, brace in the stirrups, and take my chair seat - if only that were correct. lol I had one trainer tell me that I have over stretched my achilles tendon. Her suggestion was to “activate” my arch. For some reason that description has helped me. I thought I had conquered the problem but a couple of weeks ago I found myself sliding my right leg forward and bracing against the irons. It’s getting better again but I am constantly a work in progress. If I live to 100, I may one day be correct.
Could you have someone longe you without stirrups while doing other like windmilling with arms, twisting back and forth and such?
That can help with regaining proper balance when starting to have a bracing chair seat.
Offset stirrups, with the long branch on the outside can help a lot with this, and that “broken ankle” problem.
Offset stirrups make the foot bed more parallel to the ground, so your leg can hang more correctly and your foot can be in contact with the stirrup.
I’ve gone back to riding without my stirrups for the first 10 minutes of my ride, making sure to keep my leg draped under me. I usually will only walk and trot without my stirrups, but in the past few months I have become confident enough in my seat that I will also canter without them. (Being 68 years old, I’m quite proud of myself when I do this.)