India, May 13 -- For 11 years running, Paris Olympics relay silver-medallist Akani Simbine, who anchored South Africa to the men's 4x100m World Relays gold on Sunday and carries the world-leading 100m time this year, has gone under 10 seconds in 100m. It earned him the nickname of "sub-10 king", and a record stretch that moved him past Usain Bolt (10 years).

Yet, before the 31-year-old could make the magical mark of the sprint world almost routine, he took a while to reach that threshold. For five seasons from 2010, Simbine hovered around the mid- and low- 10s, even touching 10.19 in 2012 and 10.02 in 2014. He finally ran sub-10 in 2015, and has done so every season since.

Through those five years of pushing to break that barrier for th...