ABSTRACT
Our walking and running movement patterns require friction between shoes and ground, where we exert downwards and backwards forces ultimately resulting in forward movement. The surface of ice is characterized by low friction in several naturally occurring conditions, for example on frozen lakes or canals; this low friction can limit our walking velocity, increase its energy cost and determine a greater risk of falls and injury. More than 3,000 years ago, humans invented an entirely new form of locomotion to be employed on ice; here, they would stand on skates made of animal bones and push backwards on the ice with a pointy stick in order to move forward, similarly to what one can do on a canoe, rowing with a single-bladed paddle. Ice became a surface where travelling was faster and more economical than other forms of muscle-powered locomotion on ground, especially when skates with metal blades began to be used on Dutch canals in the thirteenth century. The first part of this chapter presents an overview of the physics of ice surface friction, and discusses the most relevant factors that can influence ice skates’ dynamic friction coefficient. The second part presents the main stages in the development of human locomotion on ice, describes the associated implications for exercise physiology and shows the extent to which ice skating performance improved through history. This chapter illustrates how technical and material development, together with empirical understanding of muscle biomechanics and energetics, led to one of the fastest forms of human-powered locomotion.
