“A runner needs not just to be skinny but - more specifically - to have skinny calves and ankles, because every extra pound carried on your extremities costs more than a pound carried on your torso. That's why shaving even a few ounces off a pair of running shoes can have a significant effect.”

British-Canadian journalist, author, and public speaker

Malcolm Gladwell is a British-Canadian journalist, author, and public speaker. He has been a staff writer for The New Yorker since 1996, and he is known for books that bring ideas from social science, business, and culture to a wide general audience. He has published eight books. He also hosts the podcast Revisionist History and co-founded Pushkin Industries, a podcast company. His work often looks at why people and institutions think and behave as they do.