The muscle activity in the powerful hindquarters of showjumping horses has been laid bare in a just-published study.
Jumping is the most popular equestrian sport, with elite horses much admired for their ability to clear high obstacles.
What makes them standout performers?
Traditional selection and training strategies for jumping horses have not been validated using instrument-based equipment to examine selection, training and competitive performance.
Lindsay St George and her colleagues set out to quantify the role of muscle function during the equine jump and its relationship to indicators of athletic performance. They went on to examine how this objective information could aid equestrian selection and training practices.
The study team collected three-dimensional kinematic measurements (relating to the geometry of motion) and data using surface electromyography — a noninvasive tool for quantifying superficial muscle activity — to quantify movement and muscle activation from horses executing a submaximal jump.
They used seven mares and 10 geldings of various ages, heights and breeds, with different levels of jumping skills and competition experience.
They were grouped based on their ability to raise their center of mass during the jump suspension — a fundamental, objective measure of jumping performance.
The kinematic data allowed the study team to objectively measure equestrian-derived preferences for movement traits related to impulsion, engagement and joint articulation.
They said the surface electromyography offered insights into fundamental muscle activity patterns of selected superficial equine muscles during the jumps, delivering findings that agreed with scientific literature on the functional role of equine muscles during jumping.
“Differences in muscle activation were most pronounced in the gluteal muscle during jump stride, where shorter contractions at take-off were significantly correlated with higher and more rapid vertical displacement and vertical velocity of the center-of-mass trajectory, a faster approach, shorter hindlimb stance duration at take-off and more rapid shortening of the hindlimb at take-off,” the study team reported.
“Thus, horses with a greater capacity to elevate the center of mass during jump suspension displayed a greater ability to generate muscular power and vertical impulse rapidly during jump take-off, supporting the hypotheses that horses with the greatest center-of-mass elevation exhibit desirable kinematic traits that are associated with muscle activation patterns, and differ significantly from horses with lower center-of-mass elevation.
“These findings provide objective support for equestrian preferences related to the generation of engagement, impulsion and hindlimb muscle power when selecting jumping horses and justify their prioritization as objective performance indicators for the sport of equine jumping.”
The study also highlighted the importance of power-training exercises within jump training programmes, which could support the development of improved jump technique and performance.
The study team comprised St George, Jonathan Sinclair, James Richards and Sarah Jane Hobbs, all with the University of Central Lancashire in England; Serge Roy, with Delsys/Altec Inc in Massachusetts in the United States; and Hilary Clayton, with Sport Horse Science in Mason, Michigan, in the US.
St. George, L.; Clayton, H.M.; Sinclair, J.; Richards, J.; Roy, S.H.; Hobbs, S.J. Muscle Function and Kinematics during Submaximal Equine Jumping: What Can Objective Outcomes Tell Us about Athletic Performance Indicators? Animals 2021, 11, 414. https://doi.org/10.3390/ani11020414