Why do 100 meter runners hold their breath?

Answer 1

As far as I'm aware the human body releases a different type of energy only capable of doing so when short bursts are required and sheer focus. Our bodies are amazing! Hemoglobin carries oxygen around the body but when 100 metre sprint comes along it can do even more!

Answer 2

100 meter runners do not hold their breath during the race. They take deep breaths before the race to oxygenate their muscles and then focus on rhythmic breathing during the sprint to maintain peak performance. Holding their breath would not be sustainable or beneficial for the high-intensity activity of a 100 meter sprint.