Canoeists on touch course

"This course is very very very difficult. I feel exhausted because it's difficult everywhere, you never have five meters to relax," France's Tony Estanguet (pictured), the defending singles canoeing champion told Reuters after several practice runs.

The 280 metre, semi-circular course has more of a drop than previous Olympic venues and the numerous artificial obstacles make the swirling waters unpredictable and nearly impossible to master.

"The water changes so much that every time you come down, it's different, it's new water and the water flows differently," Slovakia's Michal Martikan, a three-times Olympics singles canoe medallist said.

"This is the most difficult artificial course in the world," Martikan added.

The sheer difficulty of the course will make error-free races almost impossible, according to the coaches. That will be a major change from the Athens Olympics, where three of the four white water winners prevailed with no penalty points.

"Even for the top guys, they wouldn't feel comfortable of nailing it, so there's room for the underdog to come through here," Richard Fox, the head coach of the Australian team said.

"The way the course is configured, you just take a lot of hits on the way down," Fox continued.

Fox added that errors would add to the pressure on athletes during the race and maintaining composure would be critical.

Silvan Pobiraj, head coach of the USA team agreed, and said athletes would be challenged very differently from past two Olympics.

"Speed and strength will be less important than good boat control," Pobiraj said.

"With this kind of difficulty of the course, I think everybody will have mistakes, I don't think they'll be a perfect run."