Growing up, I was always the dumpy, unsporty one. Matt, my older brother, was the skinny one who did the running, jumping and anything requiring quickness and coordination. He seemed to excel with ease while I laboured away on a sluggish course towards sub-mediocrity. This pattern lasted until our late teens when Matt, being older, beat me to booze. While he was away on a year-long, round-the-world bender, I took up running — with a vengeance. It was time to turn the tables.

Source: Is running ability down to effort or DNA? And can it be proved? – The Guardian