How he does it: Yuval Katz says the key elements to an effective jump serve are a good toss (4-5 feet up) with topspin on the ball, a good takeoff (running start), and a quick wrist snap at the moment of contact, creating even more topspin. Photo sequence by Craig Kojima, composite by Dean Sensui, Star-Bulletin

Hawaii, which has an amazing 200 aces to go with a 25-1 record so far this season, has three of the top 10 servers in the Mountain Pacific Sports Federation. Led by sophomore Yuval Katz's 44 aces, the Rainbows have turned a basic skill into a lethal weapon.

"It is a tough skill to be good at," said Katz, who leads the MPSF in ace average and ranks fourth nationally. "The main point is to be consistent. It isn't enough to go and pound one in, then miss the next 10.

"You need to practice it. When I first started, maybe five years ago, I missed a lot. But my coach had faith in me and one day I started getting it in. It's a good feeling (getting an ace). It's a point that happens and you don't have to do anything else."

With his two aces last Saturday against Stanford, Katz became Hawaii's all-time career leader with 93. In less than two seasons, he has surpassed four-year starter Mark Presho's total of 92.

Eight Rainbows have 15 or more aces on the year while their opponents have scored 81. Seeing the fireballs in practice daily has improved Hawaii's serve reception and overall passing skills.

"These guys see the toughest serves in the country every day so they aren't intimidated by other teams," said graduate assistant Sean Scott, a senior on last year's team. "Passing is so much mental and our passers have a lot of confidence. You have to want the ball on a serve and not be intimidated.

"When Yuvi (Katz) first came last year, I was fearing for my life. It's a totally different speed than you've ever seen."

Call it warp speed. During yesterday's practice, Katz was clocked consistently at 65 mph with a JUGS gun - and he was not going full throttle. Naveh Milo, second on the team with 38 aces, was right behind at 62 mph and Aaron Wilton (15 aces) at 60 mph.

"You can't simulate Hawaii's serves and you can't tell how hard they are from film," said Stanford setter Stewart Chong, whose fourth-ranked team was tagged for 16 UH aces in two losses last week. "Not being able to pass their serves was the most difficult thing for us to absorb. If we get blocked, then that's something we can work on. If we get aced, then it's over, it's a point, and there's nothing you can do."

"It definitely bothers the other team's confidence," said Hawaii sophomore blocker Sivan Leoni, third with 27 aces. "I developed mine by trial and error, looking how other players do it. It is technically hard to learn."

The jump serve came into vogue at the collegiate level right around the 1988 Olympics. It's the one element of the sport that has had the most impact in the last eight years, said former U.S. national men's volleyball coach Doug Beal.

"I think nothing has changed the game as radically as the jump serve," said Beal. "I don't think a team can win without being good at the jump serve. When you have a small team, like Hawaii, it's a very intelligent way to gain the advantage over a taller team."

"I need other things to cover for my being short," said the 6-foot-2 Milo. "That's why I want a good serve. The other team might say, 'OK, Naveh is short, so maybe he doesn't block good.' But they have to say I pass and serve good.

"My first coach told me I shouldn't even try, that I was no good. But I practiced to become good."

Aces are easy to keep track of but Hawaii scores points in other ways because of its tough serving. Against Stanford last Thursday, the Rainbows had seven aces but also scored five other points when the service pass was returned over the net and was slammed back by UH.

"There's a couple important factors to the jump serve's success," said Hawaii coach Mike Wilton. "Strong legs are important. You have to jump high to hit it because the higher you jump, the more court you have to work with in terms of your impact area on the other side of the net.

"Putting topspin on the ball makes it bite the air, causing it to drop when it gets on the other side of the net. Most good jump servers spin the ball first, making good contact with a strong wrist snap. Palm and fingers rolling over the top of the ball imparts even more topspin."

Speed isn't the only factor with a jump serve. Timing and the toss is of the essence, too.

"Too many players take a bad toss and try to live with it," said Wilton. "The more experienced servers won't. If Yuvi doesn't like his toss, he'll let it drop and go a second time.

"Of course, sometimes he drops it on purpose to psych the other team out, giving them another 15 seconds to think about it, to be fearful. His serve IS absolutely frightening."

Wilton said even if he had more height on his team, he'd still like the jump serve in his arsenal.

"Good serving has a tendency to take away options for the opposing team," said Wilton. "The poorer the pass, the fewer the options and the more predictable they become.

"If you're a good sideout team, like we are, so what if we miss a serve. We'll get a sideout and serve another bomb at you and wear you down that way."