Meeting Abstract

73.1  Tuesday, Jan. 6  Metabolic Cost of Human Hopping: Linking Mechanics and Physiology of Locomotion GUTMANN, A.K.*; BERTRAM, J.E.A.; RUINA, A.; University of Calgary; University of Calgary; Cornell University annegutmann@gmail.com

One of the central questions in biomechanics is "Why do people and animals move the way they do?" People and animals bodies have many degrees of freedom and, thus, are capable of a wide variety of movements. But, in general, people and animals choose to execute common tasks especially repetitive tasks such as locomotion in certain predictable ways. For example, people could choose to use an asymmetrical, limping gait to move from place to place, but most choose to walk using symmetrical steps. And, on a more subtle level, people are capable of using a wide variety of step length-step frequency combinations when walking, but mostly use a preferred step length-step frequency pair. Why is this the case? We hypothesize that humans use movement patterns that consume the minimal amount of energy necessary to accomplish a specific task and that energy minimization results in consistent movement patterns. However, this leaves open questions such as, "What is the task?" and "How does cost control motion?" In this study we use human hopping (similar to the kind done when jumping rope) to elucidate how metabolic cost, mechanical variables, and physiological constraints interact to produce an observed movement pattern. Although hopping is not generally used by humans for locomotion, it is a good model for studying the principles that govern locomotion because it has many of the same characteristics of locomotion: it is repetitive and can be performed aerobically, but is mechanically simple: it can be modeled as a one-degree-of-freedom movement (movement in the vertical direction only). Thus, we use a non-locomotory movement to gain insight into the connection between the mechanics and physiology of locomotion.