John Bestebroer had a very special connection with Rie Mastenbroek. Rie won 3 gold medals and 1 silver medal at the age of 17 years at the 1936 Olympics in Berlin. At the end of her life, Rie Mastenbroek and John had weekly phone contact and they spoke about all kind of subjects.

Rie Mastenbroek died in November 2003 at the age of 84 years old.

In February 2019, Rie Mastenbroek should have been 100 years old. Because of this, John Bestebroer and the organisation Rotterdamse Sport Iconen organized a swimming event for youth in Rotterdam, the city where Rie Mastenbroek was born.  Some former Dutch Olympic swimmers were also at this event to support the children. Because of this special sport event, the city of Rotterdam gave the swimming pool the name after Rie Mastenbroek.

The Rie Mastenbroek Swim event is from now on an annual sport event and make the family of Rie Mastenbroek very proud.