Sjaak was involved in an accident at work in 2009 that resulted in the loss of his right lower arm. As an active sportsman, he went on to compete in para-swim events until he switched to para-triathlon in late 2013. National triathlon coach Bas de Bruin, encouraged him to try para-triathlon. With his good results in the pool and experience in cycling, he believed he was fit enough to start running and competing in para-triathlon events.

Sjaak worked as a farmer, growing flower bulbs on his family farm, but following his accident he now works in the administration and managing side of the business.

Recent Highlights

- Winner of the 2017 NED Paratriathlon National Championships;
- Winner of the 2016 NED Paratriathlon National Championships;
- 2nd place at the 2017 ITU World Triathlon Grand Final Rotterdam;
- 7th place at the 2016 Rotterdam ITU Paratriathlon World Championships; and
- 11th place at the 2016 Besançon ITU World Paratriathlon Event.