Namiko Yanagawa, who lost her hearing at age 1, led the women's national volleyball team for the deaf and hard-of-hearing until last year, and is well-versed in the challenges the sport poses to those with hearing difficulties.

"Since players are not capable of talking to each other during a match, they communicate with sign language during a timeout," Yanagawa, 28, said via written messages. "But they won't be able to play well if they fail to discuss enough until each of them is fully satisfied."

Yanagawa's passion for the sport goes back to childhood, but she first learned of volleyball for deaf people — which follows the general competition rules — during her first winter at university.