Oscar Bos, marine ecologist Imares Texel: 'That bag really becomes your opponent'
Taking it all out on a punchbag, in a group and to rousing music. That just about sums up Kickfun - kicking and punching to you heart's content. You do need a bit of technique though, if you want to stay in one piece. Oscar Bos: 'You can let off a lot of steam in a short time. And in between bouts you train other muscle groups with pushups and abdominal exercises. The real killer is the burpee in which you jump up from pushups. The first time you do that it knackers you. But the reward comes later when you have energy enough for two.'