Accounting for the Influence of Animal Size on Biomechanical Variables

Abstract

Animal size has a profound influence on many biomechanical and physiological parameters. This chapter discusses some general principles of, and common approaches to, accounting for animal size effects, and outlines some potential pitfalls. Two common methods of attempting to account for size effects are to divide parameters by body mass, and using dimensionless parameters. An advantage of an empirical approach is that it does not require any prior assumptions as to the nature of the scaling relationship, nor any knowledge of the physical processes underlying the measured parameters. The chapter discusses the best ways of accounting for the effects of animal size on several widely used biomechanical parameters. At least three of these parameters, muscle force, muscle velocity and jump height, provide examples of measurements for which neither dividing by body mass nor forming dimensionless parameters is usually an appropriate method of accounting for size effects.