Running On Sand: 1.6 Times Harder
Question: If running on sand requires 1.6 times as much energy as running on a hard surface, why would anyone do it? Answer: for the same reason we run, rather than drive around for three or four miles after work. In a Run Well column in the New York Times, Jen Miller directs us to an interesting study on beach running by researchers at St. Luke’s University Clinics in Belgium. That work reveals lots of mathematical relationships useful mainly for locker room chatter with other runners. Here we go: Walking on sand requires 1.6-2.5 times more mechanical work than does walking on a hard surface at the same speed. In contrast, running on sand requires only 1.15 times more mechanical work than does running on a hard surface at the same speed. Walking on sand requires 2.1-2.7 times more energy expenditure than does walking on a hard surface at the same speed; while running on sand requires 1.6 times more energy expenditure than does running on a hard surface. The increase in energy cost is due primarily to two effects: the mechanical work done on the sand, and a decrease in the efficiency of positive work done by the muscles and tendons. Bottom line, running on sand is a great way to train for running on anything, including more sand.