The effect of conformation on orthopaedic health and performance in a cohort of National Hunt racehorses: preliminary results.

The study investigates how the physical shape or structure (conformation) of horses used in National Hunt races can influence their performance and their risk of injury. Over two years, the researchers observed 108 of these racehorses, recording their health and performance as well as meticulously measuring their physical properties.

Research Methods

• The racehorses’ conformation was measured in three dimensions using computerized techniques.
• Various statistical models were used to study the effect of conformation on race performance and injury risk. Multiple regression models examined performance while logistic regression models assessed injury risk.
• The study looked at several specific conformation aspects, such as the width between the lower jawbones (intermandibular width), the angle of the shoulder joint when flexed (flexor angle), the angle between the major pelvic bones (coxal angle), overall body girth, the length of the hind digit, and irregular alignments of specific limb joints (valgus conformation).

Results

• Performance improved with increases in intermandibular width, shoulder flexor angle, and coxal angle.
• The performance decreased when the girth or hind digit lengthen, or valgus conformation of one of the limb joints increased.
• The risk of certain injuries, such as to the tendon in the lower limb (superficial digital flexor tendon) or the pelvic bone, varied with changes in conformation. For example, the risk of pelvic fracture increased with valgus conformation of the tarsus (a joint in the hind limb) but decreased with increasing coxal angle.

Conclusions

• The study found that valgus deformation (when joints are out of alignment) could negatively affect performance or increase risk of injury.
• The coxal angle was unique in that it affected both the performance and the risk of injury.
• The researchers supposed that an alignment of the muscles with the axis of the pelvis could benefit force transmission and decrease the strain on the musculoskeletal structure.
• The study’s findings are preliminary and may not have enough statistical power, meaning further larger-scale studies would need to be conducted for more definitive results.
• Nevertheless, the study suggests that understanding the effect of conformation on racehorse performance and injury risks could help in spotting horses that are likely to perform well and avoid injury on the racecourse.