The article also mentions exercises to improve your balance (easy-medium-hard) and mentions Tai Chi as one of the major drivers of good balance. Tai Chi indeed helps you practice your balance physically, and it also has neurological impact on your brain to keep you agile and in balance. My experience shows that Nordic Walking has similar impact: We may not stand on one leg for too long, but the way we use our poles in a steady pendulum rhythm, and the way we negotiate difficult trails with slopes, mud, roots and rocks certainly helps us with balance.
I would be interested in hearing from you in the comments; what is your experience with balance and Tai Chi (or Nordic Walking) . The article is below.