Sun Valley is the only conference that really trains both: your mind and your body. The schedule allows it. There is content in the morning and sports in the afternoon. It is interesting to see that many of the most successful people in the world are also the fittest. While over half of America is overweight or obese I would say that only 20% of Sun Valley attendees are (this is a personal guess).
In my case I confess that I train hard before attending Sun Valley. I am probably not the only one. To me Sun Valley is both a conference and a sports event. During the conference which ended yesterday I was mountain biking 2 to 3 hours a day and did so in the company of amazingly smart and fun cycling buddies.
Allen and Co has found a great formula that trains the mind and body. To practice sports at conferences makes sense. And it is not only to be fitter. When you meet people practicing tough sports you bond, and bonding is stronger than networking.