Career
Together with Wil Hartog and Boet van Dulmen, he was part of a contingent of Dutch riders who competed at the highest levels of Grand Prix racing in the late 1970s. Middelburg never earned a factory-sponsored race bike, yet managed to post some impressive results. His best years were in 1979 and 1981, when he finished in seventh place in the 500cc world championships.
Middelburg was killed while competing in a road circuit race in Tolbert, the Netherlands in 1984.
(key) (Races in bold indicate pole position. Races in italics indicate fastest lap).