Tools and strategies to improve human locomotion performance and safety throughout history: on ice skates, skis, mountains and the battlefield

Humans have developed tools and strategies to improve locomotion performance and safety throughout history. In particular, unusual environmental conditions and danger have pushed the limits of imagination and initiative, laying the foundations for the development of several tools to enhance locomotion. This Review summarises studies on the biomechanics and energetics of human locomotion on ice and snow, from a historical perspective and in load-carrying conditions. Environmental conditions challenge our locomotor performance: steep mountain paths and snow on the ground increase the metabolic cost of walking, ice increases the risk of falls, and fighting on the medieval battlefield required protection. In these conditions, humans evolved and developed tools and strategies to improve their locomotor performance and safety, typically with a trade-off between increasing the weight carried and reducing the metabolic cost of locomotion and/or increasing safety. Materials engineering and empirical understanding of muscle and locomotion biomechanics have aided performance improvement. In addition, environmental and even genetic changes have contributed to a superior physiological performance at high altitude. This Review presents and discusses findings integrating the biomechanics and energetics of locomotion. Overall, the thought-provoking historical perspective of this work helps to hypothesise some of the current technological and technical limitations to human physiological performance and highlights how improving the latter may well require a wide multidisciplinary approach.