"If it's not on Instagram. it didn't happen" - one of the great maxims of our time. Well, perhaps not quite. But regular runners and adventure enthusiasts are increasingly recording their outdoor exploits to boost their social media profiles. Whether it leads to a lucrative endorsement from Red Bull or just an inclusion to the next instalment of People Are Awesome - or some cool footage to show your friends - consider a headcam an investment. Here, Dave Taylor rounds up the best.