Career
At the age of 14, De Maar was ice skating in the winter and cycling in the summer. He had better results in cycling. The second year was not so good, and after his contract ended in 2002, he did not get a new contract.
De Maar found a different team, "Löwik-Tegeltoko".
In 2003, he performed better, although he had no victories. Still, the Rabobank team decided to sign him again.
In 2004 and 2005 he rode in the Rabobank Continental Team. De Maar signed with Quick-Step for the 2011 season, but moved to UnitedHealthcare for the 2012 season.
In the 2012 Tour of Britain, de Maar took the victory on the fifth stage.
With 9 kilometres (56 mi) left, he hit the tarmac with two other riders after taking a corner too wide. He slowly picked himself up, got back on his bike and reintegrated the group. He rode away solo 6.5 kilometres (40 mi) from the finish, and crossed the line with an advantage of 15 seconds on the chasers.
In September 2014 it was announced that De Maar would join the new Team Roompot team for 2015.