Jason Burnett catches his breath as he climbs off the trampoline after completing a training routine full of astonishing flips and twists upwards of 20 feet in the air.
The Olympian walks directly to a TV screen and plays back video of his performance, scrutinizing every millisecond.
Propelling oneself to such extreme heights and breathtaking acrobatics requires a trampolinist to be conditioned precisely and to be acutely aware of what each body part is doing at every instant. Feet hitting the trampoline bed at the wrong time, the wrong angle or with insufficient power won't give the athlete enough air or velocity to perform the skills (moves) and earn points from the judges.
Canada's Olympic hopefuls in trampoline are immersed in the science of success. Their coach, Dave Ross, has a degree in physics and is an equipment innovator with a sophisticated sense of how a trampoline moves and reacts. They also rely on specialists in biomechanics, Pilates, ballet, performance psychology and strength and conditioning to tune their bodies and minds to succeed in an explosive 20-second event where every degree of movement is crucial.
Here at Ross's trampoline club, Skyriders Trampoline Place, Burnett, a 2008 Olympic silver medalist, trains with the other two Canadians who will compete at the 2012 London Summer Olympics: Rosannagh MacLennan and Karen Cockburn.
MacLennan is the 2011 Pan American Games gold medalist and Cockburn has two si lver medals and one bronze from the last three Olympics.
When healthy, the Toronto-born trio aims for nine training sessions a week on the trampoline, split over six days, full of numerous brief but explosive intervals on the apparatus with small rest periods.
The sport takes its toll on the body. MacLennan suffered a concussion in May; Cockburn and Burnett have both recently dealt with plantar fasciitis, a painful inflammation on the bottoms of their feet.
Competing on such stiff, powerful trampolines is a far cry from bouncing around on the sort found in backyards. The average backyard exerciser may land with approximately 2 g to 5 g (gravitational force), or two to five times body weight, depending on height of the jump. So a 150-pound person, for example, may land with about 300 pounds of pressure pushing down on his body – mainly the knees, hips and ankle joints.
Compare that to Canada's Olympic trampolinists, who often soar as high as a two-story building and land with between 15 g and 18 g of force.
"Imagine 18 clones of yourself standing on your shoulders and try to do a squat without collapsing – that's what these athletes feel in the trampoline bed," Ross said. "Gymnasts throw around their body weight, so they need to be small. Trampolinists also throw around their own body weight, but they also have to be strong enough to overpower the forces of the trampoline."
Strength and conditioning specialist Chris Chapman has designed a unique regimen to train Burnett, 25, MacLennan, 23, and Cockburn, 31.
In non-Olympic years, he has incorporated adrenalin and risk into the training with boot camps full of high-ropes courses, mountain biking and mixed martial arts training. During Olympic seasons, the athletes run, bike and row in repetitive sprint intervals.
The women, both less than 120 pounds, and the 150-pound Burnett, strength train with Olympic weightlifting and heavy-weighted jumping drills for leg and core power.
"They are only in the trampoline bed for 0.3 of a second on every bounce, and of that 0.3, they only have 0.1 to push back into the bed to go up again," Chapman said. "So we have to train them to fire their muscles quickly, so they can produce extreme amounts of force in a very small time. Energy-system wise, their 20-second routines may be similar to a 200-metre sprint – 20 seconds of all-out work."
The trampolinists also work with ballet and Pilates instructors to hone balance, posture and flexibility, and consult a sports psychologist about the fear factor. But they build sharp spatial awareness with pure trampoline experience. The head and stomach feel rare sensations while flipping and rebounding. Plus there is the demands of positioning in the air during acrobatics, especially when aiming for a target painted in the middle of the trampoline which appears tiny from such heights.
"It's hard to replicate the sensations of the trampoline in any other workouts," MacLennan said. "If you take a week away from the trampoline, it can take up to two weeks to get that spatial awareness back. You get really dizzy when you come back to it."
The elite trampolinist can translate how things feel on the trampoline into how they will look to the judges. New to the sport, flight time is now factored into the difficulty score. (That is, the amount of time the athlete spends in the air on each bounce is calculated by sensors beneath the trampoline.)
Trampolinists are scored for height and degrees of difficulty, with points deducted for loss of height, breaks in form and travel across the trampoline. Canada's three Olympians work on the finer details with sport biomechanist Carolyn Taylor.
Taylor films their routines. Sometimes, from underneath the trampoline with a high-speed camera to capture every millisecond from the bottoms of their feet up.
"A lot my focus is what they do when they are in the trampoline bed, because whatever happens in the air is determined by what happens in the bed," Taylor said. "Once you are airborne, you can't change your angular momentum. It's a matter of developing as much angular momentum as possible when you're in the bed, so you can use that to manipulate the velocity and the rate of twisting or somersaulting."
When twisting through the air, Burnett has been known to rotate at an astonishing 1350 degrees per second or 900 degrees per second somersaulting. He holds a world record for degree of difficulty.
With video of routines shot at 120 frames per second, Taylor can teach the athletes using slow-motion video, helping them perfect precise details.
"I think the most about travelling across the trampoline – that's my biggest weakness right now, and I always want to be on the target as best I can," Burnett said. "I am always thinking 'Where are my arms?' because if you are directing them up, you'll go up. If they are directed forwards or backwards, you will travel accordingly. The arms keep you in control and the rhythm of the bed keeps you high."
Using the software program Dartfish, Taylor can overlay a performance of a Canadian athlete with one of a competing trampolinist on the same screen, frame by frame – something Cockburn finds valuable.
"The video is very eye-opening, and because I'm hard on myself, so I see lots of little mistakes," she said. "But when I can see video of a Chinese athlete laid over a video of my performance, I can see there aren't too many differences between me and the top scorer. You have to be a perfectionist in this sport."
The trampoline World Cup season has just begun, and Canada's trio will fine-tune their Olympic routines there, travelling to compete in Albacete, Spain, this weekend.
This is the fifth in a 10-part series on the science behind athletes' preparation for the London 2012 Summer Games. Next week: the marathon.