Sean Manseau, CSCS, is founder of Pioneer Valley CrossFit in Hadley, Massachusetts. He has been training CrossFit since 2005, and by his best calculations, has taught a little over 8,000 classes. He earned his CrossFit Level 2 by the skin of his teeth (but on the first try) in 2009, and is a little bummed he might have to relearn the sumo deadlift high pull and the medicine ball clean to test for his L4.

Before becoming an instructor of CrossFit, he has been, at various times, a janitor, a guitarist in a hotel show band, a grocery stock boy, a receptionist, a bike messenger, an animator, a video game artist, homeless, a muay Thai instructor, a bartender, a novelist, and a medical experiment volunteer.