But will women ever be as fast as men? After two record-breaking performances at the London Marathon, some wonder if there is any biological barrier that humans cannot overcome.
Sawe shatters two-hour marathon goal
Elite endurance: Following record-breaking performances at the London Marathon by Sebastian Sawe and Tigst Assefa, experts are questioning whether there are any biological barriers left that humans cannot overcome. Glossary
Destined - Developing as though certain to happen because of fate or a particular plan.
Sceptical - To have doubts or reservations. The philosophical theory of scepticism holds that some knowledge is impossible.