The sound is supplied via underwater speakers. Synchronized swimmers do not touch the bottom of the pool during a routine. It is against the rules, and a two-point deduction will be given if they do. The water is a minimum of nine feet deep. The swimmers create the illusion of standing on their feet or hands because they are so proficient at the techniques of eggbeatering and sculling.
Synchronized swimmers swim with their eyes open underwater.
By seeing their teammates underwater, they make corrections to alignment and set-up for specific moves in their routine. When spinning upside down in the water, synchronized swimmers spot the pool walls just like a figure skater, dancer or diver would to count their rotations. In a five-minute routine, a synchronized swimmer may spend up to a minute underwater without coming up for air. At the same time, they are using their arms and legs to suspend themselves in the water. It's similar to running underwater while holding your breath at the same time.