Jamaica’s Usain Bolt crosses the finish line to win the gold in the 200-meter final in a record time of 19.30 seconds at the Olympics today. Associated Press Photo.

BEIJING — Usain Bolt. Insane speed.

The Jamaican wunderkind hurtled to his second world record and his second Olympic gold medal, finishing the 200-meter race today in 19.30 seconds to break Michael Johnson’s 12-year-old mark.

Bolt became the first man to break the world record in both the 100 and 200 at the same Olympics. Not since Carl Lewis in 1984 has any man doubled in the Olympic 100 and 200.

He had this one won about halfway through, but unlike his record-setting performance in the 100 four nights before, there was no hot-dogging, no celebrating until he crossed the line. He went hard all the way, looking at the clock down the stretch, leaning at the line, knowing that Johnson’s venerable mark was within reach.

When he saw the number come up — a number that never has before — he raised his arms, then fell flat to his back, arms and legs outstreched, and basked in the roar of the Bird’s Nest crowd.

It is no understatement to call him not just “The World’s Fastest Man,” but maybe the greatest sprinter of all time.

He also will compare well to Jesse Owens, one of the eight other men to pull off the double at the Olympics.

Wallace Spearmon of the United States finished third but was disqualified for leaving his lane, a decision that U.S. officials protested. He was celebrating along with Bolt — even picking up his friend — carrying the American flag around the track for several minutes after the race and was shocked when an official told him of the DQ.

That gave Churandy Martina of Netherlands Antilles the silver medal and Shawn Crawford of the U.S., the defending Olympic champion, the bronze.

Indeed, they were racing for second. Martina finished in 19.82, incredibly more than a half-second behind Bolt.

Bolt is simply a different kind of runner — coiled power in his 6-foot-5 frame, supposedly too big for success in the 100, but certainly built to run the 200.

His move out of the starting block isn’t nearly as important in the longer race, which makes this more about raw speed. But a good start certainly doesn’t hurt. He got one in this race, bursting out of the blocks from Lane 5, overcoming the lag about a quarter of the way through, then beating Martina to the line by four body lenghts.

Bolt’s 100 record is 9.69 seconds. He averaged 9.65 per 100 meters in the longer sprint, running into a very slight headwind.

“Incredible,” Johnson, now the former record-holder, said after the race. “He got an incredible start. Guys of 6-5 should not be able to start like that. It’s that long, massive stride. He’s eating up so much more track than others. He came in focused, knowing he would likely win the gold and he’s got the record.”

Bolt won the race on the eve of his 22nd birthday and a version of “Happy Birthday” played over the public-address system as he took off his gold shoes and wrapped the Jamaican flag around his shoulders like a scarf.

He did another hip-swiveling dance, then raised his hands and pointed toward the scoreboard. A little later, he posed near the scoreboard — the traditional picture that all world record-setters take. Bolt now has three of them — this, the 100 from Saturday and the picture he took in New York in May when he broke the 100 record the first time.

“You’re back there giving it everything you’ve got — it’s brutal,” said Kim Collins, the 2003 world champ who finished seventh. “He’s doing it and making it look so simple. Michael Johnson did it, and it didn’t looked that easy.”

Bolt’s victory made Jamaica 3-for-3 in the Olympic sprints, and the women’s 200 Thursday will include three Jamaicans with gold-medal potential — Veronica Campbell-Brown, Sherone Simpson and Kerron Stewart.

None of them, however, will surpass what Bolt has done at these games. And while Michael Phelps and his eight swimming golds may be The Story of these Olympics, Bolt’s sheer dominance in the most basic tests of speed there are will not soon be surpassed — unless he does it himself.

In another final on the track, Melaine Walker of Jamaica won the gold medal in the women’s 400-meter hurdles in an Olympic record.

Walker won in 52.64 seconds, with Sheena Tosta of the United States taking silver in 53.70 and Tasha Danvers of Britain third in 53.84.

The hurdles final was wide open with world record-holder Yulia Pechonkina skipping the Olympics because of a heart problem, two-time world champion Jana Rawlinson out injured and reigning Olympic champion Fani Halkia expelled after testing positive for a steroid.

Aksana Miankova of Belarus won the gold medal in the women’s hammer throw in an Olympic record.

Miankova, who entered the games with the third best throw of all time after two Russians who were either banned or under investigation for anti-doping violations, set the record with her next-to-last mark of 250 feet, 5 inches today.

Two-time world champion and Athens 2004 silver medalist Yipsi Moreno of Cuba hit the lead briefly at 245-1 in the fifth of six rounds. She finished with silver at 246-8.

China’s Zhang Wenxiu had the crowd on its feet and roaring louder with each of her six attempts, the world championship bronze medalist finishing third at 243-10.

Earlier in the evening, American Bernard Lagat advanced to the 5,000-meter final, hoping to salvage his Olympics and maybe start a rally for the struggling U.S. track team.

Lagat won his heat in 13 minutes, 39.70 seconds to move on to Saturday night’s medal race. He didn’t qualify for the 1,500-meter final, adding his name to a list of high-profile American flame-outs at the Bird’s Nest.

The U.S. team entered Wednesday with only three gold medals, and two of them came from the most unlikely of sources — discus thrower Stephanie Brown Trafton and 100-meter hurdler Dawn Harper.

Meanwhile, Lagat, Tyson Gay, Sanya Richards, Lolo Jones and Reese Hoffa have all been disappointments. Of the five gold-medal contenders, only Richards got anything — a bronze after she blew a big lead in the 400-meter final.

Lagat, who won silver and bronze medals for his native Kenya in the 1,500 at the last two Olympics, was hoping to double in the 1,500 and 5,000 for the U.S.

He became an American citizen in 2004 and at last year’s world championships — his first major international competition for the United States — he won both races.

In the 5,000, he was among the top four entering the final lap and used a strong finishing kick to pass everyone.

In the first of three heats, American Matt Tegenkamp sliced through the lead pack in the final straightaway to win in 13:37.36 seconds.

In the 110-meter hurdles semifinals, world record-holder Dayron Robles and Americans David Oliver and David Payne all made it to the final, to be run Thursday without China’s top runner, Liu Xiang, the defending Olympic champion, who withdrew with a foot injury Monday.

In the women’s 200-meter semis, Americans Allyson Felix, Muna Lee and Marshevet Hooker all advanced, as did the Jamaican trio of Veronica Campbell-Brown, Sherone Simpson and Kerron Stewart. The Americans are hoping to avoid a replay of the 100 final, where Jamaica swept the medals.

In the men’s 800, where the U.S. is not considered a medal threat, Nick Symmonds advanced past the first round while Andrew Wheating and Christian Smith failed to make it out.

Smith is the runner who memorably dove across the finish line at the U.S. Olympic trials to earn the third and final spot in Beijing.

He said he knew he’d need to run a personal best simply to advance at this level, but his time of 1:48.20 was 3 seconds off that and nowhere close to what he needed to earn a wild-card spot.

The top two runners in each heat automatically advanced, but Smith was more than a body length out of second place and said diving was not an option.

“I can’t even compare it to any football fields I’ve been to,” Smith said of the Bird’s Nest. “I wanted so badly to get to the next round, but the race was slow. I felt all right, but couldn’t close with those guys.”