When an athlete boosts, signals from pain travel up the spinal cord and induces autonomic dysreflexia, a condition that increases heart rate and elevates blood pressure to dangerous levels

When Canadian para-athlete Martin Larocque wheeled onto the track for the 100-meter final at the 1992 Paralympic Games in Barcelona, Spain, I felt invincible. In the warm-up area, the then-25-year-old from Embrun, Ont., Drank a gallon of water and positioned his bent knees tightly against his chest in the racing chair. Before being ushered to the start line, I have reached down and pressed hard on his gut to compress his ready-to-burst bladder.

Moments later, I felt a familiar rush. The hairs stood up on the back of his neck, his pupils dilated and he started to sweat. I have felt alert and ready, awaiting the bang of the start gun. Larocque was "boosting" – a potentially life-threatening form of self-harm used by athletes with spinal cord injuries to enhance performance.

In 2010, a team of researchers led by Dr. Yagesh Bhambani at the University of Alberta published an anonymous survey of athletes with the ability to boost. Nearly 17% admitted to boosting.

Doping without drugs

Described as "doping without drugs," it only works in people with spinal cord injuries at or above the sixth thoracic vertebra, located just under the shoulder blades. These athletes have a blunted response to exercise, meaning they are unable to increase heart rate and blood pressure in line with the demands of sport. To beat it, they can use various forms of self-harm to trigger a "fight or flight" response.

Larocque chose to compress his full bladder, but he said that he has competed with athletes who have thumbtacks or fastened a tight strap over an open wound to get the same effect. "It does help. It does enhance your performance, "Larocque said.

Autonomic dysreflexia

When an athlete boosts, signals from pain travel up the spinal cord and induces autonomic dysreflexia, a condition that increases heart rate and elevates blood pressure to dangerously high levels. But the spinal injury prevents pain signals from registering in the brain, so the athlete can not feel it. If the cause of pain is not removed and their blood pressure remains elevated, the potential for seizure, stroke, or heart attack can be fatal. The trade-off: power and speed.

The International Paralympic Committee has banned athletes from competing in a dysreflexic state, intentional or not, since 1994. The organization's medical and scientific director, Dr. Peter Van de Vliet, says the policy is aimed at protecting the health of athletes, and only be sanctioned for anti-doping violations if intent were demonstrated.

The World AntiDoping Association does not recognize boosting as a prohibited method and is "satisfied with the way boosting is controlled under the IPC medical rules," according to spokesperson James Fitzgerald.

Doping or not, the potential for harm is real – and with glory on the line at the Invictus Games, some competitors may think boosting is worth the risk. And if they do, it's hard to detect the difference between an induced physiological response and an accidental one.