- GB's Katie Archibald wins gold in women's omnium
- Kristina Vogel (Ger) wins women's sprint gold
- Jordan Kerby (Aus) wins men's individual pursuit
- Men's points race GB's Mark Stewart 7th
A mass-start race of 40km (160 laps). Points are scored in intermediate sprints, which are held every 10 laps, with five points for the winner followed by three, two and one for the next three over the line. There are also 20 points on offer for lapping the field.
Tactics vary, with some riders sitting at the back to conserve energy and contest the intermediate sprints, while others try to gain a lap by breaking off the front and rejoining the back of the main bunch. The winner is the rider with the most points at the end of the race.
A straight race against the clock over 4km. One rider starts on the back straight, one on the home straight but they are competing against the clock rather than each other.
The quickest two riders in qualifying contest the final, where to win you must catch the other rider or be first to complete the distance.
The omnium has had a major overhaul following the Rio 2016 Olympics, changing from a six-race event over two days to a four-race event held on a single day.
The new format consists of four bunch races, with the scratch, elimination and points races retained and a new event - the tempo race - added. This also means the omnium is now a pure endurance event instead of a test of sprinting and endurance.
Points are accumulated by riders in the first three events - the scratch, tempo and elimination races - with 40 points for the winner, 38 for second, 36 for third and so on.
Each point then won during the final event - the points race - is added to the rider's points total. The rider with the highest score at the end of the points race is the winner.
- Scratch race - a 10km (40 lap) race for men and 7.5km (30 lap) race for women, where the winner is the first rider over the line.
- Tempo race - a 10km (40 lap) race for men and 7.5km (30 lap) race for women, with sprints conducted every lap after the first five laps. The winner of each sprint earns one point and any rider who gains a lap on the bunch earns four points.
- Elimination race - the last rider to cross the finish line every second lap is eliminated until one rider is left.
- Points race - 25km (100 laps) for men and 20km (80 laps) for women. Same rules as the individual points race.
To qualify for the knockout rounds, riders must complete a 200m flying lap in the fastest time possible, with 28 now progressing instead of 24 at previous World Championships.
The knockout races tend to feature slow, tactical starts, followed by a frenetic finish as two riders race against each other with the first to cross the line winning - the perceived advantage being that the rider coming from behind can draft, using less energy and thus have a better chance of being victorious.
Olympic champions Katie Archibald, Elinor Barker, Steven Burke and Callum Skinner have been named in the squad of 20 riders, of whom 10 are making their World Championship debut.
Great Britain will hope to match their table-topping five gold medals from last year's event in London but are without a number of star names.
Six-time Olympic champion Jason Kenny and four-time Olympic gold medallist wife Laura, who are expecting their first child, will miss the championships, while Bradley Wiggins has retired and Mark Cavendish is focusing on road racing.
Women's endurance: Katie Archibald, Elinor Barker, Ellie Dickinson, Neah Evans, Emily Kay, Manon Lloyd, Emily Nelson
Men's endurance: Matt Bostock, Steven Burke, Kian Emadi, Chris Latham, Mark Stewart, Andy Tennant, Oliver Wood
Sprint: Jack Carlin, Katy Marchant, Lewis Oliva, Ryan Owens, Callum Skinner, Joe Truman
The World Track Cycling Championships 2017 are taking place at the Hong Kong Velodrome from the 12-16 April.
The Championships take place every year, last year they took place in London. They were first held in 1893, in Chicago and were originally for amateurs with separate professional races. Amateurs and professionals continued to competed in separate events until 1993, after which they raced together in "open" races.
Championships are open to riders selected by their national cycling association. They compete in the colours of their country.