Comparison of speed-dependent time, force and spatial parameters between Franches-Montagnes and European Warmblood horses walking and trotting on a treadmill.

Speed alterations affect many gait analysis parameters. How horses adapt to speed is relevant in many equestrian disciplines and may differ between breeds. This study described changes in gait parameters in 38 Warmblood (WB) and 24 Franches-Montagnes (FM) horses subjected to an incremental speed test at walk (1.35-2.05 m/s) and trot (3.25-5.5 m/s). Time, force and spatial parameters of each limb were measured with an instrumented treadmill and analysed with regression analysis using speed as the independent variable. With higher speeds, stride rate, length, over-tracking distance and vertical ground reaction forces increased while the impulses decreased. The parameters followed the same linear or polynomial regression curves independent of breed, while the slope (linear) or incurvation (polynomial) often differed significantly between breeds. Some differences between the breeds were associated with height and speed (e.g. stride length at walk), and would disappear when scaling the data. The main differences between the breeds seem to stem from the movement of the hind limbs, with the FM obtaining long over-tracking distances despite the shorter height at withers. Some parameters relevant to gait quality could be improved in the FM to resemble WB movement by strict selection using objective measurements systems.

Prediction of continuous and discrete kinetic parameters in horses from inertial measurement units data using recurrent artificial neural networks.

Vertical ground reaction force (GRFz) measurements are the best tool for assessing horses' weight-bearing lameness. However, collection of these data is often impractical for clinical use. This study evaluates GRFz predicted using data from body-mounted IMUs and long short-term memory recurrent neural networks (LSTM-RNN). Twenty-four clinically sound horses, equipped with IMUs on the upper-body (UB) and each limb, walked and trotted on a GRFz measuring treadmill (TiF). Both systems were time-synchronised. Data from randomly selected 16, 4, and 4 horses formed training, validation, and test datasets, respectively. LSTM-RNN with different input sets (All, Limbs, UB, Sacrum, or Withers) were trained to predict GRFz curves or peak-GRFz. Our models could predict GRFz shapes at both gaits with RMSE below 0.40 N.kg-1. The best peak-GRFz values were obtained when extracted from the predicted curves by the all dataset. For both GRFz curves and peak-GRFz values, predictions made with the All or UB datasets were systematically better than with the Limbs dataset, showing the importance of including upper-body kinematic information for kinetic parameters predictions. More data should be gathered to confirm the usability of LSTM-RNN for GRFz predictions, as they highly depend on factors like speed, gait, and the presence of weight-bearing lameness.

Subjective and objective evaluations of horses for fit-to-compete or unfit-to-compete judgement.

At Fédération Equestre Internationale (FEI) competitions, horses undergo veterinary inspection for judgement of 'fit-to-compete'. However, FEI Veterinary Delegates (VDs) often differ in opinion. The aim of the present study was to evaluate intra- and inter-observer agreements of fit-to-compete judgement and compare these with objective gait analysis measurements. Twelve horses were evaluated by three experienced VDs and one veterinary specialist and video-recorded for re-evaluation later. Simultaneously, quantitative gait analysis measurements were acquired. Inter-observer agreement during live evaluations was fair (κ = 0.395, 58% agreement). Intra-observer agreement between live observations and videos at one and 12 months was 71% and 73% respectively. Sensitivity and specificity of motion symmetry measured with quantitative gait analysis system were 83.3% and 66.7% respectively, against the consensus of all observers as a reference. These findings might suggest that more VDs should be used to adequately judge fit-to-compete. Quantitative-gait-analysis may be useful to support decision making during fit-to-compete judgement.

Effects of body mass on microstructural features of the osteochondral unit: A comparative analysis of 37 mammalian species.

Since Galileo's days the effect of size on the anatomical characteristics of the structural elements of the body has been a subject of interest. However, the effects of scaling at tissue level have received little interest and virtually no data exist on the subject with respect to the osteochondral unit in the joint, despite this being one of the most lesion-prone and clinically relevant parts of the musculoskeletal system. Imaging techniques, including Fourier transform infrared imaging, polarized light microscopy and micro computed tomography, were combined to study the response to increasing body mass of the osteochondral unit. We analyzed the effect of scaling on structural characteristics of articular cartilage, subchondral plate and the supporting trabecular bone, across a wide range of mammals at microscopic level. We demonstrated that, while total cartilage thickness scales to body mass in a negative allometric fashion, thickness of different cartilage layers did not. Cartilage tissue layers were found to adapt to increasing loads principally in the deep zone with the superficial layers becoming relatively thinner. Subchondral plate thickness was found to have no correlation to body mass, nor did bone volume fraction. The underlying trabecular bone was found to have thicker trabeculae (r=0.75, p<0.001), as expected since this structure carries most loads and plays a role in force mitigation. The results of this study suggest that the osteochondral tissue structure has remained remarkably preserved across mammalian species during evolution, and that in particular, the trabecular bone carries the adaptation to the increasing body mass.