Do you have any thoughts on which is preferable in badminton? I've asked my coach who has very neutral gait, he said doesn't matter as long as its not pronation. Could you add to this at all?
Erm, obviously I'm not Jonas. But.... I assume we are talking about foot striking attitude. Both over-pronation and over-supination are bad. They often occur together: for example, I over-supinate, then I pronate too much and too late. Note that a small degree of supination, followed by a small pronation, is part of a "neutral" gait. If you over-pronate or over-supinate, custom-made orthoses can help. It also helps to activate your core abdominal muscles -- specifically, transversus abdominis, which is the deepest abdominal muscle, the weakest, and the most important for posture and balance. Unfortunately, most people have no idea how to use transversus abdominis. It's very hard for most people to find, because the stronger muscles (rectus abdominis and the obliques) tend to take over instead.