Reaction time is important for any level of game, being fast and ready as soon as the opponent hits the shuttlecock will give you a great advantage you will be ready to move quickly and prepare for the right response.

An exercise I could use is audible signals to start my movements off, either on a badminton court or outside. When the signal is heard sprint for 20 - 30 meters, then change direction only when the coach gives the signal. In 30 seconds, the coach can give the signal 5 to 6 times.

Another exercise I could use is working on my footwork focusing on a fast start, aiming at 4 or 6 corners, then go back slowly to the center of the court. Your first partner facing you, will give you a signal with their hands, the second partner will be behind you and give me audible signals, with variations on when the signals are sent. 6,8 or 12 moves to the corners, repeated 5 to 8 times depending on your level.