[2] In 1996 Groenendaal joined the newly formed Dutch cycling team Rabobank which he would stay with until the end of the 2006–07 season when he choose to ride for an individual sponsor.

[3] In the following season, Groenendaal dominated cyclo-cross with wins in the Superprestige series and the World Cup as well as being number one UCI ranked rider.

Groenendaal started as a big favourite for the World Championships but suffered a crash during the race and did not recover and as a result lost his Rainbow jersey.

Groenendaal won the first race of the Gazet van Antwerpen trophy of the 2002–03 season with the Koppenbergcross ahead of Nys and Wellens.

In the 2008 UCI Cyclo-cross World Championships Groenendaal helped Dutch National teammate Lars Boom to launch his attack at the start of the final lap and win the gold medal.