1 - Not at the same time right? (Using peripheral vision.) 2 - Only eyes move between opponents and shuttle? (Not my head?) 3 - Can only do it if they defensive clear? 4 - Stroke timing gets totally screwed up (Can't fire a full arm smash, wrist/check smash still possible)
eyes must always be on shuttle the moment it leaves the opponent's racket until you hit it with your racket therefore the net/lines/opponent's position all must be perceived with peripheral vision and what elite sports athletes call the "third eye" ... which is a constant awareness of the 3d space around them
Understanding where a player was when they hit the shuttle, and moving to retrieve it is mental strategy.For instance, if a player smashes from the clear court, or you just dropped , you would find gaps at the front court and rear, respectively. Takes experience beyond just hitting and returning shuttles.
when u play with ppl who make you move ard like crazy, you will find ways and means to do that as well. especially when you play with some of the older folks, find the gaps is better than smashing at them.
Split second practice. Comes with experience. You need to have the speed to wait for the shuttle and then have a little peek at it. Six sense. How about some cock eye? aha. Just kidding.