The MdS demands that you carry everything with you; all your clothes, food and bedding. Water is dished out on a daily basis and the other important thing they provide is shelter in the form of row upon row of bedouin tents. I have been running with a pack weighing just over 5 kilos for about a month now. The pack is the OMM Classic 32L, kindly donated by Outdoor Warehouse up in the Lake District; it is designed for lightweight running events like this. To be honest, the back pack is extremely versatile. As a "retired" downhill ski racer I always hated carrying a back pack when I was recreationally skiing, but I took this one with me at the end of last year to Les Deux Alpes . Even with lunch for 4 people, warm clothing and around 5kg of camera equipment it formed very well to by body and didn't roll around which was something that used to annoy me. Initially I found it awkward to get hold of the drinks bottles at the side without swinging the whole pack around, but eventually I got used to where they were. Side waist pockets were perfect for snacks and smaller items that you needed to be easily accessible. The next test will be using it for running.