MANCHESTER, England — Ryan Lochte set his fourth world record of the week at the short-course swimming world championships Sunday. Five other world marks were also established in the final day of the meet — boosting the total to 18.

Lochte improved on his own 100-meter individual medley mark, set in the semifinals a day earlier. The American finished in 51.15 seconds, shaving 0.10 off his previous record.

Lochte also set a world mark in the 200 IM and led off the Americans' world-record swim in the 400 freestyle relay earlier in the week. The Floridian won four gold medals and two silvers.

"The 200 back takes a lot out of you," Lochte told the crowd inside the M.E.N. Arena, "so I'm glad I could step back up for this race."

The three other records Sunday were set by Markus Rogan of Austria in the 200 back, Sanja Jovanovic of Croatia in the women's 50 back, Felicity Galvez of Australia in the women's 100 butterfly, Marleen Veldhuis of the Netherlands in the women's 50 freestyle and Russia in the 400 medley relay.

Lochte, Rogan, Jovanovic, Galvez and Veldhuis all use Speedo's LZR Racer swimsuit, which has rewritten the record books over the past two months.

There have been 19 long-course world marks set since the LZR was introduced in February. Eighteen additional world records have been established at these championships. All but two of the records have come with swimmers wearing the LZR.

Federica Pellegrini of Italy used an Arena suit when she set a world record in the 400-meter freestyle at the European championships last month, and the Russian team that won the relay here is also sponsored by Arena.

Rogan can shed the label of eternal runner-up. His previous best results at Olympics and world championships were seven silvers. When he realized he had won, Rogan slammed his fist into the water to celebrate.

"I didn't think I stood a chance," the Austrian said.

Rogan finished in 1 minute, 47.84 seconds. The previous record of 1:49.05 was set by Lochte in Shanghai two years ago. Lochte finished second this time, in 1:47.91 — also better than his old mark.

Jovanovic improved on her own world record, finishing in 26.37 seconds. Her old mark was 26.50, set at the European short-course worlds in December.

Galvez's time was 55.89 seconds, which shaved 0.06 off the previous mark set by her teammate Lisbeth Lenton in 2006.

Veldhuis improved her own world record in the women's 50 free, finishing in 23.25. Her previous mark was 23.58, set in November.

The Russian team of Stanislav Donets, Sergey Geybel, Evgeny Korotyshkin and Alexander Sukhorukov took the medley relay in 3:24.29. The previous record of 3:25.09 was set by the United States in 2004.

Also Sunday, Nathan Adrian of the United States beat two-time world champion Filippo Magnini of Italy in the men's 100 free. Adrian finished in 46.67 for a championship record, while Magnini touched second in 46.70 and Duje Draganja of Croatia third in 46.83.

Magnini had hoped to use a new Arena suit that is supposed to compete with the LZR, but the suit could not be approved in time by swimming governing body FINA.

Yuriy Prilukov of Russia improved his own championship record in the 1,500 freestyle, touching in 14:22.98 — nearly a second ahead of his time from two years ago.

Suzaan Van Biljon of South Africa also set a championship mark in the women's 200 breaststroke, as did Moss Burmester of New Zealand in the men's 200 butterfly.

Oleg Lisogor of Ukraine won the men's 50 breast in 26.46, slightly off his world record of 26.17 set in 2006, and Kylie Palmer of Australia won the women's 200 freestyle in 1:54.41.