A lifetime of training came down to today for speed skater Shane Dobbin as he raced in his only event at the Vancouver Winter Olympics.

But his performance in the men's 5000m did not live up to his own expectations, and the 30-year-old managed only 17th in the gold medal race despite feeling confident that he could hit the top 10.

He clocked 6:33.38 and finished 18.78 seconds behind the eventual winner, Dutchman Sven Kramer, who won in 6:14.60 and set a new Olympic record.

Seung-Hoon Lee of South Korea took the silver medal and Ivan Skobrev of Russia finished third for bronze. Dobbin's opponent in the pursuit-style race, Canadian Lucas Makowsky, finished 13th.

Meanwhile, New Zealand's first biathlon competitor at an Olympics, Sarah Murphy, placed 82nd out of 88 competitors in the women's 7.5km sprint event.

Her time of 23min 49.7sec was nearly 4min behind Slovakian winner Anastazia Kusmina.

A despondent Dobbin said afterward that he had no idea why he had failed to perform.

"This week I've been feeling good all week, and was having to slow myself to what I thought would be race pace," he said.

"Standing on the start line I was comfortable and confident."

However, the four-time world inline skating champion said it wasn't his day on the ice.

"It's the type of sport that we're in. If you have a good day you can really shine, if you have a bad day you're chasing your laps the whole way, so it's a little bit hit and miss. Today I missed it."

Speed skating is contested with two competitors racing at once around a 400m oval. Dobbin drew the eighth round and went out hard with some quick early laps, clocking around 30 seconds in his fastest.

But his 22-year-old opponent Makowsky, with incredibly strong home support, pulled ahead slightly in the first several laps and then lengthened his lead throughout. Dobbin held on in the middle, but couldn't keep up the pace and slowed in the final circuits of the 12.5-lap race.

"At eight laps to go I knew I was starting to have to chase, and that's never a good sign," Dobbin said.

"By the time I got to mid-race everything was blurry - you lose your hearing first and then your vision in the last couple of laps.

"It wasn't my day today."

Dobbin had raced against Makowsky a few weeks ago and had beaten him "by a fairly long way".

"When I saw him pulling away from me I just couldn't respond to it and it probably hurt me a little bit mentally, when you see a guy that you know you're better than really having a good race and you're stretching.

"It's hard to come back from that."

He said the Richmond Olympic Oval, dubbed the "Slowval" by international media because of its notoriously sluggish ice, wasn't his favourite track in the world.

He had said he'd raced badly on the oval last year "and perhaps that was playing on my mind a little".

"It has a peculiar feel to it. It almost feels like your blades get stuck in the ice and you're continually trying to get out of it again - you're not skating on top of it, you're skating inside it and it's a strange feeling to get used to."

Dobbin's coach and father Roy Dobbin said his son's lack of experience that had gone against him in the race. He has only been speed skating for two years after switching from inline to ice to chase his Olympic dream.

Dobbin senior said it was now time to pull his technique apart and start again.

"We've had to take shortcuts that we didn't want to, but with more time we can pull it to bits and put it back together again the way it should be.

"He's got a very good technique considering the amount of time he's been doing it but there's still a lot of areas to work on."

However despite his disappointment Dobbin said it was still "incredible" to be at the Olympic Games and his feelings would pass in a couple of weeks as he looked forward to more World Cup races this season.

"If someone told me two years ago you're going to go to the Vancouver games I probably would have laughed at them. You have no idea how bad I was when I first started ice skating. Really terrible."

The Dobbins will now plan for the Sochi Winter Games in 2014. He will then be aged 34, and the Russian Games will probably be his last shot at Olympic glory.

"My heart's set on Sochi. I need to organise financially if I can make it that far and organise another campaign for next year. We're going to have to sit down and see what's financially possibly for next year.

"I hope to improve progressively over the next four years but I expect to be down next year. If we can get rid of the basic technical flaws that I'm still carrying now, it will be fingers crossed for Sochi."

After his gold medal win, Sven Kramer is now on track for his targeted hat-trick of golds at Vancouver's Games, as he next eyes up the 10,000m and the team pursuit.

However Dobbin said he'd seen "some chinks in his armour" this year.

"He's gonna have to watch our four years down the track," he said.

"I'm never going to go through this again. I'm not going to leave any stone unturned for the Sochi Games, I'll tell you that now."