A chain snap would do that as well. BT.
>
> Someone showed that to me at breakfast on a miniature screen. Now that
> I've watched it on a big screen I don't think it's a mountain bike.
>
No, but as Frank said he slipped off the pedal. I believe he slipped off
the left pedal first and that percipitated the fall. He was trying to
pedal harder and may have partially gone out of the saddle. Possibly he
wasn't used to that mode of powering a bike and messed up.
--
Regards, Joerg
http://www.analogconsultants.com/