Mikkelsplass, which started for Kjelsås Idrettslag, ran her first World Cup race in Lahti in March 1985 , which she finished in 18th place over 5 km. The following year she achieved her first podium in the World Cup in Falun with third place in the 30 km freestyle. After finishing fifth in the 20 km freestyle in Dobbiaco at the beginning of the 1987/88 season, she was third in Falun with the relay and in Oslo in the 30 km mass start race, thus reaching 16th place in the overall World Cup. At the season highlight, the 1988 Winter Olympics in Calgary , she won the silver medal with the relay. In addition, she achieved 24th place over 20 km freestyle and 15th place over 10 km classic. At the Nordic World Ski Championships in Lahti in 1989 , she finished 21st over 10 km freestyle and tenth over 15 km classic. In March 1991 she was third with the relay at the World Cup in Oslo. In the 1992/93 season she came in the top ten three times in the World Cup and reached 16th place in the overall World Cup. At the Nordic World Ski Championships in Falun in 1993 , she came 21st in the 30 km freestyle. The following season she won in Lahti with the relay and took second place in Falun with the relay. At the 1994 Winter Olympics in Lillehammer , she won the silver medal over 30 km classic. In addition, she achieved 14th place over 15 km freestyle. She finished the season in 11th place.
In the 1994/95 season, Mikkelsplass finished nine times in the top ten in the individual World Cup, including second place in Lahti over 10 km classic. She also won second place with the relay in Sapporo , Oslo and Nové Město . At the Nordic World Ski Championships in 1995 in Thunder Bay , she won the silver medal with the relay. In addition, she was ninth over 30 km freestyle, seventh over 5 km classic and in the subsequent pursuit and fourth over 15 km classic. At the end of the season, she achieved eighth place in the overall World Cup. At the beginning of the 1995/96 season she finished third in Vuokatti over 5 km classic. In the further course of the season she reached 11 top ten placements in the World Cup singles, including second place in Trondheim over 5 km classic and third place over 10 km classic in Kavgolovo and over 30 km classic in Oslo and was seventh in the overall World Cup. Also in the season took third place with the relay in Oslo and second place with the relay in Falun and in Nové Město . After finishing second with the relay in Kiruna and first with the relay in Davos at the beginning of the 1996/97 season, she clinched her first individual World Cup victory in Lahti over 15 km. At the season highlight, the Nordic World Ski Championships in 1997 in Trondheim, she won the silver medal with the relay and the bronze medal over 30 km classic. At the end of the season she was second with the relay in Oslo and reached 13th place in the Sprint World Cup, seventh place in the overall World Cup and fourth place in the Long Distance World Cup. In her last active season 1997/98 she came in the top ten seven times in the World Cup, including third place in the pursuit race and first place over 10 km classic in Ramsau am Dachstein . With the relay she came in second place in Beitostølen and Lahti. At the 1998 Winter Olympics in Nagano , she won the silver medal with the relay. She finished the season in sixth place in the long distance World Cup and fifth in the sprint and overall world cup. At Norwegian championships she won 13 times with the relay, twice over 15 km and over 30 km and once over 10 km and over 20 km.
Norway
Lahti
Ramsau am Dachstein