The service industry, Sean Carney has learned, is not easy work.

"There can be a lot of pressure," said Carney, the University of Hawai'i volleyball team's designated server who usually fills in for a middle blocker once a game.

UH coach Mike Wilton likened Carney's role to "asking a basketball player, 'Oh, you're coming in to shoot a free throw for this guy in a close game.' That's a tough deal."

Unlike a baseball relief pitcher or a football kicker, volleyball's pinch-server is not allowed any practice swings.

Also, in college volleyball's rally-scoring system, a missed serve is a point for the opposing team.

"It's a little scary," said John Matt Bender, who was UH's designated server as a freshman in 2003. "You come in, make one or two plays, and you're gone. Every mistake is a big deal. It tests your nerves a little bit, but it's a good way to get game experience."

After a jittery start, Carney, a second-year freshman from Iolani School, has developed into a reliable server. In the past five matches, he has committed one error in 28 serves, or an accuracy of 96.4 percent. The UH goal is to keep 90 percent of the serves in play.

In last week's sweep of Long Beach State, the Warriors scored 11 points when Carney served. He helped close out the first match with a sprawling dig.

Wilton acknowledged Carney is a better back-row defender than the middle blocker he replaces. But make no mistake: "He's in there for his serving," Wilton said. "Any time you substitute somebody for a serve, he's being brought in because of his serve."

Wilton said Carney was awarded the job because of his consistently accurate serves in practices and his poised demeanor.

"I'm glad coach has the confidence to put me in," Carney said. "It's a fun opportunity. I feel pressure, but you have to learn to deal with pressure or else you're never going to succeed in sports. Serving one ball a game is nothing compared to pressure put on the rest of the team in the middle of the game."

Because he does not know when he will be used or for whom he will replace, Carney begins "mentally preparing" during pre-match warmups.

While waiting to be summoned during the match, Carney said, "I try to keep my whole body warm. It's hard when you're standing there on the side. I know that after the game, I'm more tired from just standing there than I was from just playing. During breaks, I try to hit one or two balls. I want to keep my arm a little loose."

Carney launches spin serves off a beach jump (short toss) or jump-serve (high toss). The type of serve — and often location — depends on the style of the player he is replacing.

"Usually the reason somebody makes a serving substitution is because the other guy is struggling or the other team is passing him well," Wilton said. "You want some contrasts (in the serves)."

Carney said the job allows him to play while maintaining his other role as the understudy to starting setter Brian Beckwith.

"I'm happy to be able to contribute," he said.

Reach Stephen Tsai at stsai@honoluluadvertiser.com.