ZURICH (AP) After announcing his return to the top with a second world championship title in Beijing last month, 800-meter world record holder David Rudisha is aiming to run even faster at the Weltklasse Zurich meet on Thursday.
Rudisha has had a difficult time since breaking the world record at the 2012 London Olympics. The Kenyan missed the 2013 world championships with a bad knee and struggled to get back his sharpness.
''It has been tough 2013, 2014. I've been struggling a lot coming back,'' Rudisha said. ''I wasn't training well and after missing competition, missing training for a year, things change. My body was like uh-uh, it was like it had forgotten everything so I had to work my way up there.
''But I was always optimistic about getting back up there... The good thing is to be strong mentally and I think that helped me. This world championships was very important for my comeback. I'm now looking forward to next year which is a big year with the Olympics in Rio.''
Unlike the wire-to-wire run in London - where he became the first runner to break the 1:41 barrier for 800m - Rudisha landed the world title with a tactical race in Beijing, but he has promised to test himself against the clock in Zurich.
''1:43.5 was my season best in New York,'' the 26-year-old said. ''Since then I've been racing my races more tactical because of my preparation for the world championships, you saw I did a tactical race in Beijing.
''Now that's over I'm thinking of pushing a little bit and seeing how far I can go. I've been training very well and I believe I'm in a better shape than 1:43.5.''
Two of the favorites didn't qualify for the final in Beijing - defending champion Mohammed Aman of Ethiopia and Olympic silver medalist Nijel Amos of Botswana.
Rudisha will have to deal with Aman in Zurich as well as Adam Kszczot and Amel Tuka, who finished second and third at the world championships.
Rudisha is one of 20 individual world champions from Beijing who will be competing at Letzigrund Stadium, although the all-star cast doesn't include Usain Bolt or Justin Gatlin.
Sprint supremo Shelly-Ann Fraser-Pryce will be there, sporting another new hairstyle after clinching a third world championship with her plaits dyed green and a headband of daisies around her forehead.
''Each time I get to the championships, it's like my body knows it's at the championships,'' Fraser-Pryce said. ''Each time I start to think about my hair, to change the color, I know it's championship time.
''I'm hoping to do a personal best here.''
Fraser-Pryce did not defend her 200-meter title in Beijing but the two-time Olympic champion in the 100 will be aiming to get her first gold in the 200 at Rio de Janeiro next year - after finishing second in London.
''Next year I will be attempting both,'' the 28-year-old Jamaican said. ''When I saw the speed the 200 went at (at the worlds) I thought `OMG, thank God I wasn't in there.'
''Next year's going to be an awesome year for women's 200. It gives me a new goal to focus on. Now that I've seen the level the 200 is going in I'm looking forward to taking the step up and really going for it.''
Fraser-Pryce is unbeaten since May and another victory would secure her the Diamond Race title - one of 16 at stake.
One of the most competitive events in Zurich will be the 400, which sees the fastest six finalists from Beijing.
Wayde van Niekerk's winning time of 43.48 took the South African to fourth on the world all-time list, but LaShawn Merritt of the United States and Grenada's Kirani James will be out for revenge after finishing second and third.
Meanwhile, fresh from winning the world triple jump title with the second-farthest mark in history, Christian Taylor of the United States will try to challenge Olympic, world and European champion Greg Rutherford in the long jump.