Ten runners from Germany and Switzerland will on Sunday take part in the first ever long distance race that involves running backwards up a mountain, the organizers said.
The 11km race in the Swiss Alps is part of a "retro-running" world championship involving some 42 competitors from four countries since June, organizer Rinaldo Inaebnit said.
On Tuesday, Swiss runner Rene Hauser stormed backwards across the finishing line to win the 1,000m uphill race near Stans in central Switzerland, thought to be first competitive event of its kind.
Inaebnit, who is also a competitor, admitted that the retro-running crowd attracted some quizzical looks.
"Some don't think I'm normal, others think it's really great. But most people say they wouldn't try because their neighbor would think they aren't normal. Even dogs and cats notice and give us a funny look," he said.
Inaebnit, a devout runner forwards, stumbled across the idea while he was training in central Switzerland.
"I was on this mountain once and I tried a couple of kilometers backwards, because it's good for your muscles. I thought it was great, so I tried the whole mountain then thought of the world championship," he said.
"Forwards I need one hour and 23 minutes, and backwards two hours and 14 minutes," he added, referring to the ascent.
Running backwards is said to be tough on the thigh muscles and the training regime is arduous.
"I do three runs -- two forwards and one backwards," he said.
Weather permitting, the path up the 1,900m Stanserhorn on Sunday will be the toughest challenge in the championships. The event also included 100m, 400m and 3,000m retro-races for men and women at a local athletics track.
Roland Wegner of Germany won the men's 100m backwards sprint in 15.32 seconds. In the women's 100m, Simone Kuehn broke the 18-second barrier.