Take, for example, my favourite rugby team: newly minted world champions, the All Blacks of New Zealand. Before each game they take to the field and perform what is perhaps the most overt display of intimidation in sports today—the Haka, a Maori war dance. The team members stare with eye-popping intensity at their opposition, slap their thighs, pound their chests and roar an aggressive chant in Maori.

Did You Know?
The Maori are the first people of New Zealand, having lived there for over 700 years. Tradition holds that they arrived there from Hawai'i on the back of a whale.

While the All Blacks perform the Hakato challenge and intimidate the opposing team, an interesting physiological side-effect can also occur within athletes who engage in pre-game rituals.Scientists have found that displays of aggression and intimidation can increasethe release of the hormone testosterone.

Testosterone acts like an anabolic steroid—when levels increase in the body there are a multitude of effects, many of which might come in handy when playing a competitive sport. Testosterone can increase aggression, physical endurance and mental focus, while helping withcoordination. It can also increase a person's pain threshold and even decreases subconscious fear.

Did You Know?
Both men and women produce testosterone and although women don't produce as much, the female body is farmore sensitive to the hormone, so a little goes a long way.

While the body naturally secretes testosterone, things like diet, exercise, stress levels and, yes, displays of physical aggression and toughness can affect its production. Scientists have also proposed that competition in general can increase the production of testosterone—a theory called the "challenge hypothesis." Our ancestors likely passed this trait on to us from the days when competing for a mate or other valuable resources meant having to fight off adversaries. A rugby game or sporting match mimics these competitive conditions and the resulting effect can be an increase in testosterone concentration.

When the All Blacks perform the Haka it is quite possible that this intimidating chant causes a spike in the team members’ testosterone levels, giving them a competitive edge. Certainly,the intimidation factor of the Haka is so well-recognized that opposing teams have long been searching for ways to reduce the impact of the ritual, going so far as to suggest banning it for being unfair.

Did You Know?
The All Blacks once performed the Haka in their locker room because their opponents–the Welsh–would not allow them to do it immediately before the ball drop.

While performing the Haka can givethe All Blacks a testosterone boost, it’s important to remember that the fear and impending competition can also spike the opposing team’s testosterone too–possibly leveling out the playing field. Scientists have asked for additional studies on the subject,as it’s still unknown how much of an effect pre-competition testosterone increases can have on a person.

Either way, the Haka is a great wayto get the All Blacks–and their fans–revved up for a game.

Learn More!

Watch an All Blacks Haka!

Learn more about testosterone insports:




Learn more about the Haka in rugby:



Article first published November 3, 2011

Jalyn Neysmith

Jalyn Neysmith is a museum exhibit developer with degrees in archaeology and science communication. She loves to travel and has lived in Alberta, Ontario and Australia, and is currently at the Field Museum of natural history in Chicago. When not globetrotting she can be found running adventure races, snowboarding, or playing the fiddle.

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