The equine nuchal ligament 2: passive dynamic energy exchange in locomotion

Abstract

SummaryHead and neck movements in horses are characteristic at each gait, implying that the oscillation patterns are an intrinsic part of locomotion. In this study, we examined the head and neck movements of Standardbred horses exercising on a treadmill, and calculated the mechanical work performed by the head and neck segments at the walk, trot and canter. The position of the head and neck relative to the trunk was used to calculate the elastic strain energy stored in the nuchal ligament during the head movements of locomotion. These data allowed us to estimate the proportion of oscillatory work that is contributed by passive components of the equine neck. Elastic strain energy stored in the nuchal ligament contributes 55% of the work of moving the head and neck at the walk, and 33% and 31% respectively at the trot and canter. By substituting passive nuchal ligament work for active muscular work, the horse is able to reduce its metabolic cost of locomotion.