But are some records unbeatable? The Olympic Games in Paris this summer are likely to bring amazing performances, some of which may never be beaten.
This could be the year… of a two-hour marathon
Draining training: Kelvin Kiptum runs between 150 and 175 miles every week. Glossary
Chicago - One of the biggest cities in the USA.
Marathon - A very long running race, lasting for 26.2 miles.
Coach - Either a type of bus, or a person who trains an athlete.
Expert - Someone who knows a lot about a particular subject.