I have the exact same issue on my right foot after 30 years of poor walking, running, and all round activity. (due to Perthe’s in my right hip when I was 9)
Some things I’ve found that help me solve the ‘push off’ / ‘toe off’ part of walking, where the foot collapses and effectively whips round to the front as opposed to being swung and brought through to the front:
1- at toe off, concentrate / think about lifting the foot off the ground rather than pushing off. It’s a subtle difference, but it’s a real difference. This will make you have what feels like a ‘lighter’ contact with the ground too.
2- lift off from the middle of the ball of the foot / foot pad as opposed to the part of the ball under the big toe, or the part nearer the pinky toe.
3- try and feel a sensation of ‘braced stiffness’ on both the outside and inside of the ankle, below each malleolus whilst your foot is in contact with the ground. I say this lightly, because the food needs to stay loose and fluid, so it’s a fine balancing act. But it will help you keep your arch.
4- lift the foot through from toe off to heel strike as opposed to swinging it around – this will feel very strange at first.
those are some of the strategies that are working for me. As well as the rebuilding your feet exercises and some other tips I’ve received from the wonderful Kaitlin on here.
Give them a go and see what you think – I would love another perspective on them. I’m learning to walk at the age of 39! who would have thought that was needed? onwards and upwards.