Ardnt, a double world champion who also boasts two European Championship gold medals, announced the decision on his website.

In a statement, he acknowledged he was still young but said he had always wanted to bow out of the sport on his own terms.

He said many factors had contributed to his decision, including safety after a crash at Altenberg in 2015.

This is particularly relevant as Ardnt is about to become a father for the first time.

However, his absence is a blow to the German team as he was considered a medal contender for the Pyeongchang 2018 Winter Olympics in South Korea.

All of his major titles came in the four-man, with the world golds arriving in St Moritz in 2013 and Winterberg last year.

He won his European titles in Altenberg in 2012 and Igls a year later.

Alongside Putze, Alexander Rödiger and Kevin Kuske, he won the final two International Bobsleigh and Skeleton Federation (IBSF) World Cup races of the season in 2015-16 to top the standings.

Putze, meanwhile, was a pusher in Germany's gold medal winning four man team at the Turin 2006 Olympics.

André Lange piloted, with René Hoppe and Kuske also on the team.

Putze also won silver four years later in Vancouver and won three world titles during his career. 

He is retiring at 31-years-old.