The Long Mountain race is 31 kilometres long, has an ascent of approximately 2200 metres and marks the fifth stage of the competition.

Athletes start in Sierre at 570m and then climb up to the highest point at 2425m at Nava over the course of 24km.

Then the final seven kilometres is downhill, culminating in a frantic sprint through Zinal to the finish line at 1680m.

The route is known as 'la course des cinq 4000' because it takes the runners on a scenic trail with views of five mountain peaks over 4000m.

These are the Weisshorn (4506m), Zinalrothorn (4221m), Obergabelhorn (4073m), Matterhorn (4478m), and Dent Blanche (4357m).

In the men's race, eight-time winner and record holder Kilian Jornet of Spain returns and is the men’s favourite, but he will face significant competition from a very deep field.

There are many returning runners who have performed well in past races.

Eritrean Petro Mamu was second in the highly competitive 2019 race and he showed that he is in good form by winning the FlettaTRAIL last weekend.

Juan Carlos Carera of Mexico was fourth here in that 2019 race, in a time that would have won it in previous editions.

Brit Andrew Douglas, the reigning World Cup men’s champion, came sixth in 2019 and will undoubtedly be determined to better that.

Douglas' compatriot, Robbie Simpson, is also one to watch, having finished second in 2018 and fifth in 2019, as well as coming third in the World Championships in 2015 and second in the European Championships in 2014, showing real consistency.

In the women's race, Swiss Maude Mathys is clear favourite after winning the 2019 and 2020 editions.

In 2019 she broke the course record which had stood for 16 years.

Mathys has also won the Mont Blanc Marathon and Olla de Nuria this year and she was also the winner of the 2019 European Mountain Running Championships.

She is currently fourth in the world rankings.

Lucy Murigi of Kenya is the current women’s world number one and cannot be discounted.

She was world champion in 2017, came second in the final standings of the 2019 World Cup, has won La Montee du Nid d’Aigle and won bronze at Grossglockner this year.

She has won at Sierre-Zinal three times, in 2015, 2017 and 2018.

Judith Wyder of Switzerland was second in 2019.

She is a two-time winner of DoloMyths, most recently this year, and is another native to keep an eye on.

The women's elite race is scheduled to begin at 10:30am local time while the men's elite race is due to begin 15 minutes later at 10:45am.