When the coronavirus outbreak forced organisers to cancel marathons in the Japanese city of Nagoya, they turned to tech to ease the disappointment, offering runners the chance to race alone.

The Nagoya Women's Marathon and Nagoya City marathon were scheduled for March 8 and expected to attract some 20,000 runners -- a potential health hazard during a global pandemic. So instead of having racers run together, organisers have offered up two apps to allow participants to complete the marathons alone, tracked online.

"It's the first time the annual marathon events were cancelled, and it's the first time we launched apps to replace the real ones," one of the organisers of the Nagoya city marathon told AFP.

Instead of running the original route, registered participants can run wherever they like -- keeping an appropriate social distance -- and the apps measure and verify their performance. There are two apps -- one for those who want to finish the marathon in one go and another for those who want to complete it by running over several days.

Runners can complete the marathons between March 8 and May 31, the official race website says. The organisers said on their website that they wanted to respond to the spirit shown by those who trained for the now-cancelled races.

But they "don't recommend running in a big group," the official warned. Those who are registered for the women's event and complete the marathon via the app will receive a T-shirt and a necklace as originally promised for finishers.

The coronavirus has wreaked havoc on the international sporting calendar, with the Tokyo marathon among the early fixtures to be affected. Organisers cancelled the amateur portion of the race scheduled for March 1, affecting around 38,000 runners, who were not offered a refund.

They will, however, be eligible for a spot in 2021's marathon. The pandemic has also forced the postponement of the Tokyo 2020 Olympics and Paralympics to next year. Japan has so far recorded over 3,600 coronavirus infections and 73 deaths.