In 2001, a group of clinicians caring for professional athletes (the Concussion in Sport Group) published the first of a series of consensus guidelines on concussion, recommending that athletes who experience concussion rest until “completely asymptomatic.”1(p8) The intent of these guidelines was to prevent athletes from playing while in a vulnerable state, which involves risking greater injury. Rest was presented as a first-line treatment, with the thought that it would both prevent physiologic stress and allow healing. Once athletes were asymptomatic, they were progressed along a rehabilitative pathway. However, no definition was provided for the term asymptomatic, and no time limits were placed on rest, and as a result, rest often continued for weeks or months. With new iterations of the guidelines, the recommendations about rest became more directive: “The cornerstone of management is physical and cognitive rest until symptoms resolve.”2(p197) Clinicians began to use extreme physical and cognitive rest as a treatment for concussion, dubbing this approach cocoon therapy—no sports, no physical activity, no screens, and no social interaction. This approach was more restrictive than the management of severe brain injury, in which rehabilitation was begun as soon as patients could tolerate it.3