When I buy running shoes these days, video analysis is almost always part of the service offered by specialist sports stores. It is very popular with customers and deservedly so because it helps the shop staff to help me to make the right choice of shoe and, speaking as that awkward customer trying to choose from the large pile of shoes at my feet, it helps me to relate the feeling I am getting from a shoe to what it’s doing on the ground. It reassures me that I’m making a good choice.