DES MOINES, Iowa — Mentally, Tyson Gay is in a good place.Physically, too. That’s the healing power of running fast at nationals. Once and for all, Gay put to rest any questions about his surgically repaired hip as he completed the 100-200 sprint double Sunday at the U.S. track and field championships, winning the 200 meters in 19.74 seconds. It’s the fastest time in the world this season. Gay also beat Justin Gatlin in the 100 on Friday in a season-leading time of 9.75.“I’m pretty tired,” Gay said. “I’m just glad I’m leaving the race healthy.”With his strong performance, Gay delivered an emphatic message to the rest of the world, and more specifically Usain Bolt: The Gay of old is back.Not the version hobbled by nagging injuries over the years, but the one who captured the 100 and 200 titles at the 2007 world championships. “I’m just happy to be healthy,” Gay said. “It feels good, man.”In the women’s 200, former LSU standout Kimberlyn Duncan upset Olympic champion Allyson Felix. Duncan finished in 21.80, with Felix 0.05 seconds behind. Felix said she got a late start on training and hasn’t completely found her racing form. She skipped the 100 earlier in the week to be more prepared for her signature event, the 200. “I’m lacking a little bit of speed right now,” Felix said. “Overall, my conditioning could be a little better.”It was a busy day to finish nationals, with one final after another in rapid succession. Other winners include Alysia Montano (800), Jennifer Simpson (5,000), Duane Solomon (men’s 800), Ryan Wilson (110 hurdles), Bernard Lagat (5,000), Erik Kynard (high jump), Riley Dolezal (javelin), Evan Jager (3,000 steeplechase), Dalilah Muhammad (400 hurdles), George Kitchens (long jump), and Ryan Whiting (shot put).Olympic pole vault champion and indoor record holder Jenn Suhr cruised to a national title. Local tiesFormer TCU standout Jessica Young finished eighth in her semifinal heat in the 200 with a time of 23.46. She was 14th overall.Wallace Spearmon, who trains in Arlington, finished fourth in the men’s 200 in 20.10.Former Texas A&M standout Ameer Webb, who won the NCAA 200 title two weeks ago, was fifth at 20.20.