9. The German Markus Jürgens holds the marathon world record in backward running. At the 2017 Hannover Marathon, he crossed the finish line in a time of 3 hours, 38 minutes and 27 seconds.
10. In contrast to men, women usually run the second half of a marathon faster than the first. They tend to hang back more than men at the start, but continue to increase speed and finish strong in the second half of the race. This is what Professor Eric Allen and Patricia Dechow found when they analyzed 300,000 results from the Chicago Marathon.
11. One study looked at the impact of running on sex and orgasms. 78 runners began running four times a week. After nine months, they reported they were having 30% more sex. Plus, the number of orgasms they achieved increased by 26%.
12. The Kenyan Dennis Kimetto is the fastest marathon runner in the world. He set the world record of 2 hours, 2 minutes and 57 seconds at the 2014 Berlin Marathon.
13. The fastest runner in the world is the Jamaican sprinter Usain Bolt. He holds the world record in the 100-meter dash (9.58 seconds) and the 200-meter dash (19.19 seconds). His maximum recorded speed is 44.72 km/h (27.8 mph).