INDIA, Feb. 22 -- Remember the saying: No pain, no gain? These words rescued me during my second 42.2km race at the 2013 Mumbai Marathon. All was okay until the first 22 kilometres, when pain shot through my right leg. I stopped running. I just stood in one spot and teared up.

Then, a small voice inside me said, 'No pain, no gain'. I started walking. Ten minutes later, the same voice urged me to jog. I tried to but couldn't for long. So, I took turns walking and jogging. I only thought about meeting my family and friends at the finish line. Quitting was not an option. After 4 hours and 56 minutes, I finished!

From then to my personal best of 3 hours 36 minutes at the Berlin Marathon (42.2 km) in 2018, I have come a long way and I couldn't...