Basculing in elite show jumping horses: a motion analysis study of trunk and neck movement

The movement of the trunk and neck plays a crucial role in training and assessing the technical performance in show jumping horses. The term ‘bascule’ describes a rounded and harmonious jumping movement characterised by an arched or bulged back and a lower, stretched neck position. However, there is a lack of consensus in the literature regarding the specific kinematic features that define basculing. The question remains whether the impression of a rounded back is the result of spine flexion into an upward curved position or a combination of thorax elongation and a downward movement of the neck. Additionally, the timing of these movement components remains unclear. To address these questions, we conducted kinematic analyses on six ridden show jumpers with varying levels of competition experience. Using a simplified kinematic model, we analysed the trajectories of the trunk length, trunk height, neck length, and trunk-neck angle throughout different phases of a jump over a single 130 cm vertical fence during a training session. Furthermore, we explored potential differences in basculing execution based on the horses’ competition levels. Our findings indicate that the horses’ body posture while jumping over the fence does not exhibit true flexion of the thoracolumbar spine, resulting in an upward arched shape of the spine. Instead, during the take-off phase, the trunk shows elongation, suggesting a reduced curvature of the spine in this region, accompanied by a downward movement of the neck. However, we consistently observed a shortening of the neck segment, indicating flexion of the cervical spine. Correlation analyses suggest that these changes are associated with the horses’ level of competition, with more pronounced basculing observed in horses with higher competition levels.