When I was in high school running XC, there was a female runner I would see at invitationals who had longer, think hair. Had it braided and kept the end in a ball/knot. I thought it was convenience, but then one of the runners on the our girl's team was running next to her and that other runner turned her head back and forth a bit and our runner said that the other girl used the knot as a bit of a weapon. Our runner was more miffed at that as she was passing the girl, and we all had a bit of a chuckle.
I have said before that I really like big hair. Michelle Akers was for a long time my favorite female soccer player and her big hair was no small part of that favoritism. However i recognize that any hair that can capture wind slows players down by some amount. It does not have to be big and fluffy even loose ponytails that blow out behind a player slow that player down by a measurable amount. The energy needed to stream the hair out behind a play is taken from the effort the player is expending to run. The amount of slowdown is, usually, not great but it is also not trivial. I still like big hair but I also think players with long or fluffy hair might be better off with that hair in a bun or cut off to maximize their speed. Of course there is an advantage to the long fluffy hair. It can draw a red card if other players get their fingers tangled in the hair during a challenge then the result would be a hair pull and an automatic red card.