ATHENS - AUGUST 25: Jamie Staff of Great Britain (L) and Jens Fiedler of Germany (R) battle it out during the men's keirin heat 2 in the men's track cycling keirin second round on August 25, 2004 during the Athens 2004 Summer Olympic Games at the Olympic Velodrome within the Olympic Sports Complex in Athens, Greece. (Photo by Mike Hewitt/Getty Images) *** Local Caption *** Jamie Staff;Jens Fiedler

London 2012 - The Keirin race is unique because riders follow a motorised pace bike who leaves the track just over 600 metres before the finish. Here the riders start the gold medal race as the motor bike arrives.

London 2012 - The camera finds German Maximillian Levy among the six cyclists competing for gold in the men’s Keirin final.

Jason Kenny of Great Britain competes in the Men's Keirin Finals race on Day 11 of the Rio 2016 Olympic Games at the Rio Olympic Velodrome on August 16, 2016 in Rio de Janeiro, Brazil.

Azizulhasni Awang of Malaysia celebrates after winning the Men's Keirin First Round Repechages on Day 11 of the Rio 2016 Olympic Games at the Rio Olympic Velodrome on August 16, 2016 in Rio de Janeiro, Brazil.

Azizulhasni Awang (bronze medal) of Malaysia wins ahead of Hugo Barrette of Canada the Men's Keirin First Round Repechages on Day 11 of the Rio 2016 Olympic Games at the Rio Olympic Velodrome on August 16, 2016 in Rio de Janeiro, Brazil.

Matthijs Buchli of the Netherlands, leads Sam Webster of New Zealand leads the pack of Francois Pervis of France, Callum Skinner of Great Britain, Azizulhasni Awang of Malaysia, Krzysztof Maksel of Poland and Angel Pulgar of Venezuela during a Men's Keirin First Round race on Day 11 of the Rio 2016 Olympic Games at the Rio Olympic Velodrome on August 16, 2016 in Rio de Janeiro, Brazil.

Joachim Eilers of Germany, Damian Zielinski of Poland, Jason Kenny of Great Britain, Matthijs Buchli of the Netherlands, Azizulhasni Awang of Malaysia, Fabian Hernando Puerta Zapata of Colombia line up behind the derny driver during a Men's Keirin Finals race on Day 11 of the Rio 2016 Olympic Games at the Rio Olympic Velodrome on August 16, 2016 in Rio de Janeiro, Brazil.

London 2012 - After the pace bike pulls off, Sir Chris Hoy revs up to win an exciting gold medal race in the men’s keirin.

21 Sep 2000: Florian Rousseau of France (centre) Wins Gold, Gary Neiwand of Australia (left) Wins Silver and Jens Fiedler of Germany takes Bronze in the Men's Track Cycling Keirin Final at the Dunc Gray Velodrome in Bankstown on Day Six of the Sydney 2000 Olympic Games in Sydney, Australia. \ Mandatory Credit: Mike Powell /Allsport