Measuring Volumetric Changes of Equine Distal Limbs: A Pilot Study Examining Jumping Exercise

SIMPLE SUMMARY: When horse athletes exercise, forces are applied to their legs during each step. Repetitive loads applied during training and competition contribute to stress of leg structures. Swelling (i.e., local fluid accumulation) in the legs is a sign of increased stress in these structures. Currently, horse riders and trainers make training decisions based on visual observations of horse leg swelling, which are potentially subjective and imprecise. The aim of this study was to develop a low-cost, noninvasive method to measure lower leg volume in horses, as well as to assess the ability to detect differences before and after exercise. The tablet-mounted scanner measured increased lower leg volume after jumping, compared to scans before exercise. This method may serve as an objective tool for horse riders and trainers to prevent injury by modulating horse training frequency and intensity in response to physiological signs of stress, like leg swelling. Scans may also be used to seek veterinary consultation and treatment, as well as to guide rehabilitation from injury. ABSTRACT: Equine athletes can incur musculoskeletal injuries due to repetitive loading during training and competition. Prior to signs of lameness, horse trainers and veterinarians may observe swelling in the distal limbs, where injuries most frequently occur. Early observations may guide modulation of training to manage physiological stress and mitigate risk of injury. However, these observations of changing limb volume can be subjective and imprecise. The aim of this study was to assess the accuracy and applicability of a tablet-mounted, 3D scanner to measure and record distal limb volumes of horses before and after exercise. Users recorded scans of a cylinder of known volume with errors up to 8%. Experienced users’ measures were biased (i.e., consistently overestimated). The scanner was able to detect statistically significant increases in volume for both fore and hind limbs after one jumping session (310–2058 cm(3)). Age and intensity of workload may play a role in magnitude of limb swelling, but had mixed conclusions between fore and hind limbs. More studies with additional horses must be performed to solidify these relationships. The evaluated 3D scanner is a low-cost, accessible tool that was able to detect changes in limb swelling as a result of exercise and mechanical stress. With continued research, this information may guide training programs to decrease injury and maximize performance of equine athletes in the future.