Horse–rider interaction

Introduction

Unlike humans, horses have no selective pressure for load carrying ability as it is not an action they would naturally undertake and incurs a proportionate increase in metabolic cost [1]. Despite this, domesticated horses are regularly required to carry the additional mass of a rider whilst undertaking complex or high speed movement.

Load carrying

Applying a load to horses does not affect stride length or frequency [2] but increases stance and decreases swing time and is directly related to increased vertical limb force and associated stress and strain in limb structures. As stance time is increased, despite increased ground reaction force (GRF) impulse, the increase in peak vertical force is minimised. Mechanisms to reduce forces are of particular interest in racehorses due to the high peak GRF they experience and associated risks of stress fractures or tendon injuries. The location of the load is important, influencing the risk of overloading limbs or loading weaker lumbar regions increasing the risk of spinal injuries. […]