The practice of “boosting” is common amongst wheelchair-bound athletes trying to gain an advantage but is, in fact, deadly.

It involves blocking off catheters or sitting on the scrotum in order to fill the bladder before tapping on them – resulting in autonomic dysreflexia in the brain.

Athletes gain greater oxygen flow and a power boost from this.

However, it increases the heart rate and blood pressure, which pose a strong risk of heart attack or stroke to those with spinal cord injuries.

While it affords a ten per cent advantage, certain competitors face a very high risk of death by boosting.

International Paralympic Committee medical and scientific director Peter Van de Vliet said: “The problem with the pathology of a spinal cord injury is that this response is deviated to the cardiovascular system, including hypertension and increased heart rate.

“About 30 to 40 out of 4,300 athletes for Rio are vulnerable to this mechanism.”

The IPC’s chief medical officer Wayne Derman said: “People think that the Paralympics is a more benign version of the Olympic Games and that it is not as pointed, as targeted and as fierce.

‘That is such a wrong misconception.”