This is pure adrenaline - your heart rate increases, blood vessels constrict, and air passages dilate in response to the sympathetic nervous system. On August 7, 1974, New York City held its breath as Philippe Petit danced across the sky on a 61 metre long steel tightrope suspended between the World Trade Towers, 417 metres above ground. Fast forward to 2011, Sébastien Montaz-Rosset and his crew have dropped the balancing bar, loosened the tension of the rope for more bounce, and are pushing adrenaline to sky-high limits - anywhere from the Swiss Alps to Paris and even the fjords of Norway.

Experts such as Montaz-Rosset have termed this new sport: Highlining - a combination of rock climbing, slacklining and tightrope walking. While Petit used a steel cable, these days the structure and fabric of the line is made of flat nylon webbing to keep it from rolling under the athlete's foot. Unlike a tightrope in high tension, the highline is slack with only a measure of tension. This makes the line easily susceptible to wind and any small shift in weight, bouncing the line like a trampoline and making the walk that much more of a dynamic challenge. Falls in this sport are therefore often and those involved prefer to use a fall leash which links the climber back to the main line though some daredevils defy this safety measure by stepping out with only a small parachute pack as protection.

Sébastien Montaz-Rosset is a professional mountaineer, athlete and ski instructor and guide. Stationed behind a camera, he's not easily perturbed when it comes to filming in extreme conditions. He is an outdoor man in constant contact with nature and armed with camera, experience and talent, he has brought us amazing high definition footage of fellow highliners (see video above). A sneak peak of the trailer for his latest creation entitled I believe I can fly (Flight of the frenchies) - available on November 14 - features the rush of physical endurance, mental concentration and emotional stability mixing together as these athletes tread across the Norwegian sky and drop into unscalable depths. We had a chance to speak with Sébastien about his films and his exceptional experiences.

Sébastien, what is your background and how did that lead you to highlining?
I have always been a sport enthusiastic from an early age, as I grew up in a ski resort called Les Arcs in France, and I always had a deep passion for outdoor sports. I tried highlining for the first time three years ago and realized it was the most intense feeling of all the things I had ever tried before. The adrenaline rush you get when you succeed in traversing a line 1000 metres above the ground is just indescribable.

What was your very first film?
The first one that reached a pretty large audience was called Send it Sistah. It is 24 hours spent with two girls rigging their own line and making attempts on it and about how they share their passion.

What initially attracted you to this sport?
As a slackliner: the fact that there is nothing around you. Your link to solid ground is a 26-millimetre sling under your feet. It is an incredible sensation of freedom but also very destabilizing! As a filmmaker: the esthetic beauty of it and its incredible photography. I like everything there is about it: an original unknown activity in a mountain environment.

How do you prepare for a filming expedition?
The shooting type I really appreciate is introspective documentary. I am less and less interested in pure action films. I want to tell incredible stories of unique personalities in extreme sports to a very large audience to inspire people and to send a message. It means that I tend not to plan too much. I know a starting point and the athletes goals in what they want to achieve but I let them make their own choices, whether it is a mistake or not. I simply film as it happens. Too much planning kills the magic of the moment. While shooting I believe I can fly (Flight of the frenchies) we met incredible people and so many unpredictable things happened during the shooting. When you watch the documentary you realize that nothing is fake, people can feel that we tell them the truth.

How do you train to stay fit?
Get out everyday, run, ski, climb, fly. It is about balance and you can work on it in so many different activities.

Since a highline cannot be set on your own, how is it anchored on either side?
This sport is a paradox. Without your friends, you cannot accomplish anything but once you are on the highline, the concentration is so intense that you cannot hear anything, cannot see anybody cheering you; you are so deeply absorbed. You separate in two teams, one stays on the main peak, the other abseils down and climbs up again with the highline attached to the back of a harness. Then we pull from both side with pulleys and blockers, sometimes even up to 1000 kilos of tension.

What are some hidden dangers that become evident with experience?
Self-confidence. Like any other mountain sports, if you feel too confident because of having done these thing so many times, sometimes you don’t concentrate and make mistakes in rope work or jibbing the line. Other dangers are the natural dangers of mountaineering: crevasses, rock falls, altitude sickness, and storms. That is the game, and we accept and like it!

Your film speaks about the dream of complete freedom. Could you describe what that freedom feels like on the highline?
Buy a highline kit, go and set it up in your nearest park. You feel alive? Great! Next, put the line higher on the tree. Get in touch with a friend of a friend who knows highliners. Test it, experience it yourself. You will either never approach it or never stop.

Out of all your adventures with this sport, which one has been your highlight so far?
The highlight was definitely our trip to the fjords of Norway with Julien and Tancrède, both base liners (a combination of highlining, free, solo, and base jumping). They have pushed the boundaries of their sports and they are pioneers in what they love the most: highlining and flying. This combination is something new, it is visually very strong. The documentary is not about action sports so much as about fear, doubts, laughs, failures and how you can find the strength to live your dreams. We experience these feelings everyday in our lives, trying to make the best choices for our families and us. Common guys with doubts and dreams are telling you their extraordinary life. This could be your life.

When you are not working the cameras, how do you occupy your time?
Well, I direct all the projects: from finding the right people, to shooting, editing, grading, and translating. It is a lot of time in front of the computer. The editing is very satisfying, taking pieces of stories to make it comprehensible for most people. It is very creative, I love it! I am a mountain guide professionally so when I am not filming, I am either training or guiding people to summits around the world.

Merci bien Sébastien et bon courage!

Experts do warn not to jump onto a highline without any experience, so if this sounds like your cup of tea, slacklining in parks may be a good start. As Sébastien suggested, start low to the ground and work your way up into the skies and the ultimate adrenaline rush.

Find out more about Seb Montaz and his documentaries on his adventure video blog.

The trailer of Seb Montaz’ upcoming 40 minutes documentary I believe I can fly (Flight of the frenchies) will go online on Monday November 14 on his site at www.sebmontaz.com together with a 15 minutes free preview.

We will also keep you posted about this stunning film on our Facebook page!