Marianne Muis is a former medley

Medley swimming

Medley is a combination of four different swimming styles into one race. This race is either swum by one swimmer as individual medley or by four swimmers as a medley relay...

 and freestyle

Freestyle swimming

Freestyle is an unregulated swimming style used in swimming competitions according to the rules of FINA. The front crawl stroke is almost universally used during a freestyle race, as this style is generally the fastest...

 swimmer from The Netherlands, who competed in three consequentive Summer Olympics for her native country, starting in 1988

Swimming at the 1988 Summer Olympics

The 1988 Summer Olympics took place in Seoul, South Korea. The swimming competition, held from September 18 to September 25, was notable for the seven medals, including five golds, won by Matt Biondi, the six golds won by Kristin Otto, and the three individual golds won by Janet Evans...

. There she won the silver medal with the Dutch women's 4×100 m freestyle relay team, behind East Germany. Her twin

Twin

A twin is one of two offspring produced in the same pregnancy. Twins can either be monozygotic , meaning that they develop from one zygote that splits and forms two embryos, or dizygotic because they develop from two separate eggs that are fertilized by two separate sperm.In contrast, a fetus...

 sister and three-time Olympian Mildred

Mildred Muis

Mildred Muis is a former medley and freestyle swimmer from The Netherlands, who competed in two consequentive Summer Olympics for her native country, starting in 1988. There she won the silver medal with the Dutch women's 4×100 m freestyle relay team, behind East Germany...

was on the same silver winning team.