BEIJING (AP) Kerri Walsh is used to playing every day - sometimes three times a day - on the professional beach volleyball tours.
To her, the Olympic schedule is grueling.
"Three matches in six days; that's mentally wearing on me," she said Thursday after she and Misty May-Treanor wrapped up the beach volleyball round-robin with a perfect record by beating Norway in straight sets.
"That's one of the challenges of the Olympics. We're so eager when we get out on the court. You have to bottle up the energy and make sure you don't wear out."
May-Treanor and Walsh, who won the gold medal in Athens, beat Nila Ann Haakedal and Ingrid Toerlen 21-12, 21-15 to improve to 3-0 and retain their No. 2 seed in the medal round. The Norwegians, who fell to 1-2, made the medal round through the "lucky loser" playoff.
The other American women's team, Nicole Branagh and Elaine Youngs, was also 3-0 after completing pool play on Wednesday. Jake Gibb and Sean Rosenthal joined them there on Thursday night, overcoming two match points to beat Japan's Kentaro Asahi and Katsuhiro Shiratori 21-15, 19-21, 18-16.
"Was it even close? It didn't feel close," Gibb said with a relieved smile. "That was what we needed (to get ready for the medal round). We needed to have a sideout for the match."
The other American men's team, reigning world champions Phil Dalhausser and Todd Rogers, also qualified for the round of 16, and Brazil and China also put a pair of teams into the next round in both the men's and women's fields.
In fact, only six of the 24 beach volleyball teams in each field were eliminated after six days of pool play, a pace that gave the tournament the feel of the NHL regular season in the 1980s or a children's baseball league where every 7-year-old gets a trophy at the end.
"It's very unusual, and the Olympic draw is getting longer by a day or two each time," Australian Andrew Schacht said. "I don't think you get value for money with the pool play. But, obviously, it works better for TV and the crowd. I think the pool play is here to stay."
The Olympic beach volleyball tournament slots the teams into six pools of four, with each pair playing the others in its group. The pool winner advances to the medal round; the second-place team advances to the medal round; even two of the third-place teams advance to the medal round, with the other four third-place finishers having a chance through a "lucky loser" playoff.
The advantage of pool play is a predictable schedule, at least for the first week, and a guarantee that the audience at the venue and on TV will be able to see the top teams several times. Lesser teams have a chance to stick around, which helps build the sport in their home countries.
While many players said they understood the appeal, several also expressed a preference for the double-elimination brackets of the pro tours. The domestic tour needs just three days - four for the international circuit - to crown a champion from a field of 32.
By the third day in Beijing, half of the teams had played only once as the event crawled its way through the 13-day schedule.
"Of course," American Todd Rogers said, "I'd much rather have game after game after game after game. That's what I trained for.
"The fourth game of the day, we're still in shape and other teams may be hurting," he said, "But that's the way the Olympics roll."
The more traditional tournaments put more of an emphasis on each game: If you lose, your road to the medal stand gets more difficult; two losses and you're out. But Gibb said being at the Olympics eliminates any chance a team would take a game lightly.
"There couldn't be any more emphasis on every match," he said. "Each match for us is the biggest one of our lives."
In other matches Thursday, Clemens Doppler and Peter Gartmayer of Austria remained undefeated by beating Italians Riccardo Lione and Eugenio Amore (0-3) in two sets by the minimum four points. Wu Penggen and Xu Linyin of China also won their pool with a 3-0 record, defeating Spaniards Pablo Herrera and Raul Mesa (2-1) in straight sets.
Florian Gosch and Alexander Horst of Austria (1-2) beat Kristjan Kais and Rivo Vesik of Estonia (0-3). Brazilians Marcio and Fabio (2-1) beat Russians Igor Kolodinskiy and Dmitry Barsuk (1-2) in two tight sets. Bram Ronnes and Emiel Boersma of the Netherlands (1-2) beat Germans Julius Brink and Christoph Dieckmann (1-2).
For the women, China's Xue Chen and Zhang Xi (3-0) sent South Africans Judith Augoustides and Vitalina Nel to a third consecutive straight-sets loss. Cuba's Dalixia Fernandez and Tamara Larrea (2-1) did the same to Japan's Mika Saiki and Chiaki Kusuhara.
Brazil's Renata and Talita (3-0) beat Vasiliki Karantasiou and Vasiliki Arvaniti of Greece (0-3) in two sets. Austrian sisters Stefanie and Doris Schwaiger (2-1) beat Mexicans Mayra Garcia and Bibiana Candelas (1-2) in straight sets. Germany's Laura Ludwig and Sara Goller (2-1) dropped Efthalia Koutroumanidou and Maria Tsiartsiani of Greece (1-2) into third place with a two-set victory.
In the men's "lucky loser" matches, Gosch and Horst qualified for the medal round by beating Sascha Heyer and Patrick Heuscher of Switzerland, 21-11, 21-19, and Germans Eric Koreng and David Klemperer beat Ronnes and Boersma 21-16, 27-25 to reach the round of 16.
Qualifying through the women's "lucky losers" were Belgians Liesbet van Breedam and Liesbeth Mouha, who beat Cristine Santanna and Andrezza Chagas of Georgia, 21-13, 21-19; and Haakedal and Toerlen, who beat Garcia and Candelas 20-22, 21-12, 15-11.