The crowd can be a blur when UC Davis gymnast Stacy Wong competes in the floor exercise. But one thing is clear. Enthusiastic fan support pushes her to perform.

Wong is one of the varsity and club athletes cheered on by two athletic spirit clubs -- one of them believed to be the largest of its kind in collegiate athletics and together, a rarity in Division II of the National Collegiate Athletic Association.

"It is such a boost having so many people behind you who want you to succeed," Wong says. "You want to do well for yourself, your team -- and the fans."

Established eight years ago, the Aggie Pack boasts about 8,000 undergraduate students as members each season, and Aggie Fanatics, now in its third year, unites more than 5,500 university alumni and employees with area residents.

"They're loud, they're boisterous," says Brian Fogel, head coach of the UC Davis men's basketball team. "It makes a true college basketball environment."

The organizations generate enthusiasm and interest at UC Davis athletic contests by offering promotional giveaways as incentives for attending events.

Setting the Fanatics apart from the Aggie Pack is its outreach into the local community, which comprises about 90 percent of the organization's membership. All members receive weekly sports updates by e-mail, and to foster more interest in the UC Davis athletics program, student-athletes visit local elementary schools.

"The response to Fanatics has been amazing," says Jennifer Wong, one of a handful of students who help run the two organizations. "I see people downtown wearing Fanatics T-shirts and hats."

The Aggie Pack gets behind every varsity sport at least once during the season and some club sports, while the Fanatics supports football, basketball and gymnastics events.