Classification of collected trot, passage and piaffe based on temporal variables.
ABSTRACT The objective was to determine whether collected trot, passage and piaffe could be distinguished as separate gaits on the basis of temporal variables. Sagittal plane, 60 Hz videotapes of 10 finalists in the dressage competitions at the 1992 Olympic Games were analysed to measure the temporal variables in absolute terms and as percentages of stride duration. Classification was based on analysis of variance, a graphical method and discriminant analysis. Stride duration was sufficient to distinguish collected trot from passage and piaffe in all horses. The analysis of variance showed that the mean values of most variables differed significantly between passage and piaffe. When hindlimb stance percentage was plotted against diagonal advanced placement percentage, some overlap was found between all 3 movements indicating that individual horses could not be classified reliably in this manner. Using hindlimb stance percentage and diagonal advanced placement percentage as input in a discriminant analysis, 80% of the cases were classified correctly, but at least one horse was misclassified in each movement. When the absolute, rather than percentage, values of the 2 variables were used as input in the discriminant analysis, 90% of the cases were correctly classified and the only misclassifications were between passage and piaffe. However, the 2 horses in which piaffe was misclassified as passage were the gold and silver medallists. In general, higher placed horses tended toward longer diagonal advanced placements, especially in collected trot and passage, and shorter hindlimb stance percentages in passage and piaffe.
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ABSTRACT: The load acting on the limbs and the load distribution between fore- and hindlimbs while performing specific dressage exercises lack objective assessment. The greater a horse's level of collection, the more load is shifted to the rear and that during the passage the vertical load on the limbs increases in relation to the accentuated vertical movement of the centre of mass. Back and limb kinematics, vertical ground reaction force and time parameters of each limb were measured in 6 Grand Prix dressage horses performing on an instrumented treadmill at the trot and the passage. Horses were ridden by their own professional rider. At the passage, horses moved at a slower speed (-43.2%), with a lower stride frequency (-23.6%) and, therefore, higher stride impulses (+31.0%). Relative stance duration of fore- and hindlimbs and suspension duration remained unchanged. While at the trot the diagonal limbs impacted almost simultaneously, the hindlimbs always impacted first at the passage; the time dissociation between landing and lift-off remained unchanged. Because of the prolonged stride duration, stride impulse and consequently limb impulses were higher at the passage in the fore- as well as in the hindlimbs (+24.8% and +39.9%, respectively). Within the diagonal limb pair, load was shifted from the forehand to the hindquarters (percentage stride impulse carried by the forehand -4.8%). Despite the higher impulses, peak vertical forces in the fore- and hindlimbs remained unchanged because of the prolonged absolute stance durations in fore- and hindlimbs (+28.1% and +32.2%, respectively). Based on the intralimb timing, the passage closely resembles the trot. Compared to other head-neck positions, the higher degree of collection resulted in a pronounced shift in impulse towards the hindquarters. Despite the higher limb impulses, peak forces acting on the limbs were similar to those observed at the trot. An understanding of load distribution between fore- and hindlimbs in relation to different riding techniques is crucial to prevent wear-and-tear on the locomotor apparatus.Equine Veterinary Journal 04/2009; 41(3):263-7. · 2.29 Impact Factor
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ABSTRACT: The aim of this study was to describe the prevalence of illness and lameness at different anatomical sites in registered United Kingdom dressage horses and to identify risk factors for lameness. A questionnaire was sent to all 11,363 registered members of British Dressage in 2005, with one questionnaire assigned per horse. Four multivariable logistic regression models were developed for each section of the questionnaire. A final mixed effects logistic regression model was developed which combined the results from all prior models. Owners reported that 33% of horses had been lame at some time during their career, with 24% of these within the previous 2 years. A number of factors were associated with the occurrence of lameness in the last 2 years, including age, height, indoor arenas, horse-walkers, lunging (as protective), back problems, arenas that become deeper in wet conditions and sand-based arenas. These factors were included as variables in a final model to provide information for selection of horses, development of safer arenas and more effective training regimens to minimise the onset of lameness.The Veterinary Journal 05/2009; 184(1):27-36. · 2.42 Impact Factor
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ABSTRACT: Although anecdotal reports of increased orthopaedic injury risk in equine sports exist, there is little scientific evidence to support this. To test whether horses undertaking a single competitive sport have increased risk of specific injuries compared to those used for general purpose riding (GP); and whether injury type varies with sport category and performance level. Data from 1069 records of horses undergoing orthopaedic evaluation (1998-2003) and meeting inclusion criteria were reviewed. Sport category (GP, showjumping, dressage, eventing, racing), level (nonelite or elite) and diagnosis were recorded. Effects of sport category and level on probability of a specific diagnosis were assessed using chi-squared tests. Logistic regression was used to determine which competitive sports and levels increased risk of injury compared with GP. Overall there was a significant effect of sport category and level on diagnosis (P<0.0001). There was significant difference between anatomical site injured and sport category (P<0.0001); a high risk of forelimb superficial digital flexor tendon injury in elite eventing (P<0.0001) and elite showjumping (P = 0.02); distal deep digital flexor tendon (DDFT) injury in elite showjumping (P = 0.002); and hindlimb suspensory ligament injury in elite (P<0.0001) and nonelite (P = 0.001) dressage. There was a low risk of tarsal injury in elite eventing (P = 0.01) and proximal DDFT injury in dressage (P = 0.01). Horses competing in different sports are predisposed to specific injuries; particular sports may increase the risk of injury at certain anatomical sites; and the type and site of injury may reflect the type and level of performance. These findings could guide clinicians in the diagnosis of sport related injuries.Equine veterinary journal. Supplement. 08/2006;