Speed skater Alex Boisvert-Lacroix of Sherbrooke, Que., failed to build on his bronze-medal performance at the recent world single distance championships, finishing sixth in the first heat of the men's 500 metres at the world sprint championships on Saturday in Seoul, South Korea.

Boisvert-Lacroix's time of 35.13 seconds was less than a half-second behind reigning world sprint champion Pavel Kulizhnikov, who stopped the clock in 34.76.

"My 500m wasn't so bad. I had a good opener but I came out a little flat over the rest of the lap. The 1000m was a tough race. It had been a while since my legs hurt like that," Boisvert-Lacroix said. "I knew coming in here that this ice surface is unforgiving for pure sprinters like me."

Canada's Laurent Dubreuil, who didn't qualify for the world singles and placed eighth at last year's world sprints, was 16th in a field of 30 on Saturday in 35.42.

"My 500m was terrible," Dubreuil said. "I completely shot myself in the foot to start off the competition, which hurt my chances. However, I was able to bounce back a little in the 1000m and I'm now within striking distance of a top-10 position in overall standings."

Boisvert-Lacroix isn't as strong in the 1,000 and it showed Saturday as the 28-year-old finished 23rd among 31 skaters in a time of one minute 12.23 seconds.

Dubreuil was 15th in 1:11.23, nearly two seconds behind leader Kjeld Nuis of the Netherlands.

McLean 11th in women's 500

On the women's side, Canada's Heather McLean placed 11th of 28 in the 500m race, clocking 38.79, following a disappointing ninth-place showing at the world singles.

"I felt a lot better leading up to the race than my results indicated today. I made some technical mistakes in my 500m. As for the 1000m, it was a step in the right direction,"McLean said. "Sunday will be my last 1000m race of the season, so I will leave everything on the ice. Fourteenth place after day one gives me a lot of room to improve. I hope to move up in the rankings by coming up with two solid races."

China's Hong Zhang leads the way after a 38.11-second performance.

The 23-year-old McLean was the top Canadian at 18th in the women's 1,000 with a time of 1:18.94, nearly four seconds behind leader Jorien ter Mors (1:15.09) of the Netherlands. The Winnipeg athlete was 23rd overall at these championships last year.

With files from Speed Skating Canada