On 29 November 2021, he announced his retirement from professional cycling and took up the job of coach of the Chinese national track team.

He won the keirin after accelerating with two laps to go, winning by a wide margin and able to raise his hands and salute the crowd as he passed the finish line.

[6] His French rival, and bronze medal winner, Arnaud Tournant, said Bos' performance was "the best I've seen in a very long time."

Bos' record was beaten by Frenchman Kévin Sireau at the Moscow Grand Prix on 29 May 2009 with 9.65 seconds.

In 2017 Bos won the Dutch Championships in the team sprint with Büchli and van den Berg.

At the 2018 UCI Track Cycling World Championships in Apeldoorn he won a bronze medal in the individual 1 km time trial.

On 1 May 2009 the Union Cycliste Internationale (UCI) said "Bos’s behavior undermined the image, reputation and interests of cycling".

In the off season before 2010 Bos signed with the Cervélo TestTeam, that included former Tour de France winner Carlos Sastre.

On Stage 3 from Riemst to Genk, he edged John Degenkolb (Argos–Shimano) on the finish line in a bunch sprint to take the victory.

[13] Bos was originally selected as a member of the Belkin squad for the 2013 Vuelta a España, however he was withdrawn before the start of the race after tests revealed he had low cortisol levels.