Electromyographic evaluation of approach stride, jump stride and intermediate stride in selected superficial muscles of the jumping horse: a preliminary study

Abstract

The horse's ability to execute the diverse physical demands of jumping is greatly influenced by muscular adaptations to training. The aim of the study was to provide preliminary insight into potential differences in the functional activity of muscles recruited during phases of the equine jumping effort. An exploratory case study was conducted to investigate muscle activity and recruitment in one jumping horse, experienced in 1.40 m competition. Wireless sEMG electrodes were utilised to quantitatively investigate the degree of muscle activation by recording potentials from the Superficial gluteal (SG), Triceps brachii (TB) and Longissimus dorsi muscles. Data were collected as the horse executed a related combination of fences with a maximum height of 1.25 m. Mean motor unit action potential (mMUAP) and mean peak amplitude frequency (PAF) were determined for each muscle during approach, jump and intermediate strides, and were analysed using Friedman and Wilcoxon Signed Rank tests to establish whether significant differences occurred between strides. Statistical analyses did not reveal significant differences between mMUAP values for muscles investigated across strides (P≯0.05). However, significant differences were found for mean PAF values in the left SG between approach and jump strides (P<0.025), and between jump and intermediate strides (P<0.025) in the left TB. The lack of significant differences between strides may reflect the theory that the jump stride is a form of extended suspension incorporated into the canter stride and may support current anecdotal training methods of the jumping horse, which place emphasis on developing a regular and collected canter. However, results from this study were based on one horse and therefore application to the wider population of jumping horses should be undertaken with caution until further research in more subjects is conducted to support the results from this preliminary study.