I remember when the Berlin Wall fell and suddenly intractable problems get solved.

I think we've reached that point where we understand medically what we are doing to ourselves with these sports. In football, it's kind of hard to get the access that you want for the story and, of course, it's very long-term: the effects of the repeat concussions really don't hit until decades afterwards, whereas the traumatic injuries in extreme sports are very immediate. I realized Traumatic Brain Injury was a fascinating and important story that not had been told very much. I wanted to know more.

I don't know if people realize how hard I work, because sometimes people ask me for my secret. The truth is that I don't have any secrets apart from the fact that I've been directing theater and film for twenty years and trying at every stage to make my work better.

The world of extreme sports is also one of the big businesses. Kids might think that snowboarding is the ultimate freedom, but this freedom is being marketed to them by commercial sponsors.

I can't help seeing 'Waste Land' as the third in a triptych with my earlier films 'Devil's Playground' and 'Blindsight,' and not least in the awe and gratitude I feel for the group of people who were courageous enough to share their stories with us - and to live lives so rich in inspiration for us all.

Extreme sports tricks are becoming increasingly complex, the courses ever more challenging and crashes all too common.

The world needs more women filmmakers, so we have to keep encouraging ourselves and one another, and eventually things must get easier for us.