A lot of people use broken birds, or practice birds that are of much lower qualities during their drills. I wonder if that would have any noticeable (negative) impacts on their impacts. At the minimum, that would affect their judgement on the speed and trajectory of the shuttles. What do people in National Team use? Any thoughts?
From what I've seen, shuttles which which still have a half decent flight path are still used as practice shuttles, even if they have been used before. For a training drill, there may be a few hundred shuttles lined up, but each of these only gets hit a few times in an hour so the life seems to be extended. However, in practice games, new shuttles are used. This is what I've seen from HK squad training.
I would assume the quality of the practice shuttle would depend on what the drill is. For example, if the drill is doubles rotation smashing, then poor quality shuttles can be used since the only stroke is to smash and occasionally poor shuttle quality would even actually help in concentrating on the shuttle on such quick-tempo drill. But for most drills (especially single's drills), as long as the practice shuttle seem to have decent flight/speed, it would be acceptable since most drills are designed to imprint muscle memory of the strokes at varying positions (&endurance) and it wouldn't be a big problem with such minor adjustments to hit accurate shots with high match quality shuttles.
