In this chapter we will review how the principles of mechanics can be used to address scientific questions relating to equine performance and disease.

Performance can be defined in terms of fundamental qualities or at an applied level. Energetic efficiency, speed, acceleration, endurance capacity, stability, and manoeuvrability, are recognised as fundamental selection pressures in the evolution of terrestrial locomotion. These contribute individually or in combination to performance in a particular sport. Whereas the capacity to achieve the highest value of the outcome measure for a particular sport might be used as an overall measure of performance however, it is more useful for the purpose of scientific investigation to consider performance in terms of more fundamental quantities. The overall aim is generally to relate locomotor form (morphology), function (movement), and environmental factors to fundamental measures of performance.

Size (indicated by body mass) has an important effect on the form of the locomotor systems of terrestrial animals.