Muhlethaler took part in his first international Nordic Combined competition when he was 14 years old. In this competition over 5 km according to the Gundersen method , he impressed with a 15th place overall and was allowed to start in the 2012/13 Alpine Cup. The Alpencup is designed as a junior series for young combiners and Muhlethaler was able to develop steadily in accordance with the goals of the cup in the 2013/14 season. The 2014/15 season brought him a clear leap in the ranking of the Alpine Cup participants. With consistently good jumping results, he was able to secure good starting positions for the following individual start races, keep them in the race and regularly run into the points and even the top 15. The greatest success to date was a third place at the Summer Alpine Cup in September 2015 in Winterberg, North Rhine-Westphalia.
First podium in the Continental Cup and World Cup participation
Muhlethaler at the World Cup in Ramsau am Dachstein 2016
His constant further development was not lost on his coaches, so that at the beginning of 2015 he was allowed to take part in two competitions of the Continental Cup of Nordic Combined and in January 2015 achieved a respectable tenth place overall in Planica . Muhlethaler is a consistent and good jumper and has also improved his running performance. This resulted in his first two victories in the individual over 5 km and 10 km after Gundersen at the Summer Alpine Cup 2015 in Hinterzarten . The other competitions of the 2015/16 season brought him further podium places and another victory in the sprint in Planica.
At the beginning of the 2015/16 World Cup season , Muhlethaler started alternately in the Continental and World Cup. In the Saxon town of Klingenthal over 10 km Gundersen, he was able to achieve his first podium in the Continental Cup with a strong jumping performance and then an equally strong running performance with third place. In the World Cup he has so far lacked running constancy, so that despite the continued good jumping results he has not yet been able to convert this into World Cup points in the race.
An integral part of the World Cup team and participation in the World Cup
In the 2016/17 season , Muhlethaler was a permanent part of the French World Cup team. At the start of the season in Ruka , he won his first three World Cup points. For the rest of the season, however, it was difficult for him to reach the points, so that he drove to the 2017 Nordic Junior World Ski Championships in Park City with mixed feelings . After only finishing seventeenth in the Gundersen competition over ten kilometers, he won the silver medal behind the Austrian team together with Lilian Vaxelaire , Maël Tyrode and Théo Rochat . Muhlethaler was also able to convince in the sprint and won the bronze medal. With these achievements behind him, Muhlethaler competed at the Nordic World Ski Championships in Lahti . With the team he reached seventh place. In the individual, he was only nominated for the Gundersen competition on the large hill, in which he was 38th. After he reached the points again at the end of the season in Oslo , Trondheim and Schonach , he placed 55th in the overall World Cup standings.
In the summer of 2017, Muhlethaler started in five of the six individual competitions of the Grand Prix . In Tschagguns as well as in Planica he reached sixth place and thus achieved his best results to date at this level. In the 2017/18 World Cup , however, he was unable to confirm these achievements, so that he was transferred back to the Continental Cup after several poor World Cup races . After he was able to achieve better results there, he was called back to the World Cup team, but was again unsuccessful. In mid-March 2018, Muhlethaler won his first Continental Cup competition when he was unbeatable in the Gundersen method over 15 kilometers in Nizhny Tagil .
As in the previous year, Muhlethaler struggled in the 2018/19 World Cup and often missed the points. He achieved a surprise success at the end of January in Trondheim, where he achieved by far his best result of the season in 14th place. At the Nordic World Ski Championships in Seefeld in Tyrol , he took 28th place on the large hill, 42nd place on the normal hill and was sixth with the team. He finished the World Cup in 48th place.