It is a theory that some individuals possess a more highly-developed HPA. These individuals, called hyperkinetics and hyperdynamics, are able to tap into deeper and greater levels of power and turn themselves into veritable juggernauts of physical prowess. In the old days of the Viking conquerers, these select few were called berserkers. These were warriors who, because of an ability to trigger an extreme feeling of a life-or-death emergency within their minds and an altruistic concern to protect their family and/or comrades, were able to transcend ordinary limits of human potential, performance, and strength.
They went berserk, on the battlefield, and in the process became almost superhuman and impervious to injury. This same force, this same capability, exists in every person to a certain extent. A function of a sport is that the physical and psychological demands and pressures of a competition bring forth a greater, stronger, better man. Use a sport as a way to learn how to tap into your inner berserker qualities and as a productive way to reveal your full, unbridled power within.
From September 2010, http://raising-a-man.tumblr.com