Twelve years ago, aged 21, he broke his back when training with the SAS after his parachute failed to inflate at 16,000 feet."I should have cut the main parachute and gone to the reserve but thought there was time to resolve the problem." He landed on his parachute pack, which was like an iron bar, and fractured three vertebrae. It was extraordinary that he was alive, let alone not paralysed - but incredibly the spinal cord, which channels messages between the brain and all parts of the body, had not been severed.
Bear was treated at Headley Court, the defence forces' rehabilitation centre in Surrey. "The doctor said I was a miracle man. I had come so close to severing my spinal cord. Because of my age and my fitness, they decided I could avoid surgery." Instead, he underwent ten hours a day of physiotherapy, swimming, stretching and ultrasound treatment - a programme designed to help servicemen get back to active duty, but rarely available to civilians.
The alternative - and one offered to most people in a similar situation, but without Bear's peak fitness - is surgery to fuse the broken vertebrae. 'I had nightmares for months. Still, I was lucky to walk away without surgery - but ever since, I have suffered twinges and pains." Deep massage helped, but he says he always felt physically 'unbalanced' by his injury.
Then a year ago his wife suggested he see a Bowen therapist. The Bowen technique, developed in the 1950s, involves using rolling movements over muscles, ligaments and tendons. This is said to send impulses to the brain to trigger the body's own healing system. Precisely how it works is a mystery, but many professional football clubs maintain a Bowen therapist as it has been shown to be very effective in realigning the skeletal structure.
"I was sceptical, but wanted to keep an open mind," says Bear. He went to see East Sussexbased Bowen therapist Sarah Yearsley. "With the slightest squiggle of her fingers, it felt like petrol was being put back in my tank and I could feel all the stress seeping away. More importantly, after my back accident, my spine and pelvis had lost alignment, so I felt unbalanced." Sarah explained that Bear's pelvis was slightly twisted - and that this would cause endless problems and backache.
Most fans of Bear's Born Survivor series will not have noticed anything wrong, yet a subtle misalignment - visible only to the expert eye - can impact on total health For Bear, who is often jumping out of planes, having complete structural alignment is even more important than for the average person.
Bear describes himself as now 'hooked' and has treatment every month. It has helped him prepare for his most perilous challenge yet. Next month he is attempting a powered paraglide over Everest's 29,035ft summit.