Several years ago (when I already had screwed-up balance from my AN), a friend of mine and I did a long-range backpack trip with 60-pound packs up a gnarly canyon that was filled with boulders up to two stories high. We would climb up cracks to a dead end, retreat, scout out another way up, climb again, and hoist our packs up with ropes. The going was so tough, it took us 8 hours to go 1-1/4 miles. A day later, we went down another canyon that was just as bad. By the fifth day of scrambling cross-country, my balance felt 100% completely normal!
Unfortunately, my balance went back to the way it was before after sitting at home for a few days following the trip. But it taught me two things:
1. the brain's sense of balance does adapt, if only temporarily, if you exercise it enough.
2. you've got to exercise your balance system every day if you want to improve it
Best wishes,
Tumbleweed