PARIS, July 25 (Reuters) - Running brand On made its latest move in the supershoe race on the eve of the Paris Olympics, unveiling a marathon shoe produced by a robotic arm spraying material onto a mold to create a sock-like upper, with no laces.

On, a Swiss brand founded in 2010 and listed in New York in 2021, has been trying to muscle its way into the high-tech running shoe contest traditionally fought by market leaders Nike ( NKE ) and Adidas.

The "LightSpray" production method used in Zurich, with fewer parts required per pair, challenges the usual footwear manufacturing model which relies on shipping finished shoes from factories in South-East Asia to shoppers in the U.S. and Europe.

"In terms of scaling it, it's pretty simple, we just need more robots," On co-founder Caspar Coppetti told Reuters in an interview in Paris, where the brand demonstrated the robot - supplied by Swiss engineering firm ABB - making a shoe.

"We can move to full automation, or semi automation at least, and where it's produced is no longer as important."

The launch comes as supply chain disruptions, geopolitical risks and government incentives are driving interest in "nearshoring" manufacturing, or bringing it closer to the end customer.

The midsole, foam and plate of the LightSpray shoe are currently produced in Asia, but On aims to manufacture those elements in Switzerland too eventually, executives said.

"FRICTIONLESS"

While most running shoe innovations focus on the midsole, like the now ubiquitous carbon plate first used by Nike ( NKE ) in 2016, On argued the LightSpray shoe's thin, seamless, one-piece upper makes it light and aerodynamic.

"It's a frictionless system, basically, that will hopefully result in performance benefits," Coppetti said.

Built to be lightweight and bouncy for runners to maintain a fast pace over 42 km, marathon shoes have become big business for sportswear brands, especially with more amateurs around the world getting into endurance running.

At $330, On's shoe is at the upper end of the market, though a less eye-watering price tag than Adidas' $500 model launched last September. On's Cloudboom Strike LS weighs in at 170 grams for the men's model, against 138 grams for Adidas' Adizero Adios Pro Evo 1.

On is spending more on marketing around the Olympics than any other event this year. The official sponsor of the Switzerland Olympic team, it also sponsors Olympic athletes including Kenya's marathon runner Hellen Obiri, Poland's tennis Grand Slam champion Iga Swiatek, and Norwegian triathlete and defending gold medallist Kristian Blummenfelt.

Of 66 sponsored athletes at the Olympics, between six and 10 will wear customised versions of the LightSpray shoes, which also come in a sprint spike model.

Obiri, who left Nike ( NKE ) to sign with On in January 2022, wore a prototype version of the LightSpray shoe when she won her second Boston Marathon in April.

Not having to worry about laces coming undone during the race was a perk of the shoe, she told Reuters in an interview.

"When you wear it, you don't have any doubts," she said.