As a former dancer, I know 27+ different ways to restrain hair of all types and textures and lengths to make them indestructible and immovable for performances. I know all the tips and tricks and equipment too (ASIDE: the corkscrew pin or
spin pin is a MIRACLE invention). Now that I'm a gym mom, I know even more! I just wanted to commiserate with the original poster on this unreasonable hair requirement from her gym. My only recommendation is to see if the coaches could make an exception for your DD given the amount of time and effort it takes you to conform to the required hairstyle. Good luck!