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Hinchcliff, K. W., Kohn, C. W., Geor, R., McCutcheon, L. J., Foreman, J., Andrews, F. M., et al. (1995). Acid:base and serum biochemistry changes in horses competing at a modified 1 Star 3-day-event. Equine Vet J Suppl, (20), 105–110.
Abstract: We examined the effects of participation in each of 3 modifications of Day 2 of a 3-day-event on blood and serum variables indicative of hydration, acid:base status and electrolyte homeostasis of horses. Three groups of horses – 8 European (E) horses and 2 groups each of 9 North American horses performed identical Days 1 (dressage) and 3 (stadium jumping) of a 3-day-event. E horses and one group of the North American horses (TD) performed modifications of Day 2 of a 1 Star 3-day-event and the other group of North American horses (HT) performed a Horse Trial on Day 2. Jugular venous blood was collected from each horse on the morning of Day 2 before any warm-up activity, between 4 min 55 s and 5 min 15 s after Phase D and the following morning. Eight E horses, 5 TD horses and 8 HT horses completed the trials. There were few significant differences in acid:base or serum biochemistry variables detected among horses performing either 2 variations of the Speed and Endurance day of a 1 Star 3-day-event, or a conventional Horse Trial. Failure to detect differences among groups may have been related to the low statistical power associated with the small number of horses, especially in the TD group, variation in quality of horses among groups and the different times of the day at which the E horses competed. Differences detected among time points were usually common to all groups and demonstrated metabolic acidosis with a compensatory respiratory alkalosis, a reduction in total body water and cation content, and hypocalcaemia. Importantly, horses of all groups did not replenish cation, chloride, and calcium deficits after 14-18 h of recovery.
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Sloet van Oldruitenborgh-Oosterbaan, M. M., Spierenburg, A. J., & van den Broek, E. T. W. (2006). The workload of riding-school horses during jumping.
Abstract: REASONS FOR PERFORMING THE STUDY: As there are no reports on the real workload of horses that jump fences, this study was undertaken in riding-school horses. OBJECTIVE: To compare the workload of horses jumping a course of fences with that of horses cantering over the same course at the same average speed without jumping fences. The workload variables included heart rate (HR), packed cell volume (PCV), acid-base balance (venous pH, pCO2, HCO3-) and blood lactate (LA), glucose, total protein and electrolyte concentrations. METHODS: Eight healthy riding-school horses performed test A (a course of approximately 700 m with 12 jumps from 0.8-1.0 m high at an average speed of approximately 350 m/min) and test B (same course at the same speed, but without the rails) in a crossover study with at least 4 h between the 2 tests. Before each test the horses were fitted with a heart rate meter (Polar Electro). Blood samples were taken from the jugular vein at rest prior to the test, after warm-up before starting the course, immediately after the course and after recovery. All samples were analysed immediately. RESULTS: The mean +/- s.d maximal HR (beats/min) during the course (184 +/- 17 and 156 +/- 21, respectively) and the mean HR after recovery (75 +/- 6 and 63 +/- 7, respectively) were significantly higher in test A compared to test B (P = 0.001 and P = 0.007 respectively). The mean LA concentrations after the course and after recovery (mmol/l) were significantly higher in test A (3.6 +/- 2.7 and 1.0 +/- 0.9, respectively) compared to test B (0.9 +/- 0.5 and 0.3 +/- 0.1, respectively), (P = 0.016 and P = 0.048 respectively). The mean PCV (I/l) after the course and after recovery was also significantly different between tests A (0.48 +/- 0.04 and 0.39 +/- 0.03, respectively) and B (0.42 +/- 0.04 and 0.36 +/- 0.03, respectively) (P<0.01). The mean pH and the mean HCO3- (mmol/l) after the course were significantly lower in test A (7.40 +/- 0.04 and 28.9 +/- 1.4, respectively) compared to test B (7.45 +/- 0.03 and 30.4 +/- 2.3, respectively) (P<0.05). CONCLUSIONS: This study indicates that in riding-school horses jumping fences, even at a low level competition, provokes a significant workload compared to cantering the same distance and speed without fences. POTENTIAL RELEVANCE: This study makes it clear that the extra workload of jumping fences should be taken into account in the training programmes of jumping horses. Further research with more experienced horses jumping higher fences will reveal the workload for top-level jumping horses.
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Santamaria, S., Back, W., van Weeren, P. R., Knaap, J., & Barneveld, A. (2002). Jumping characteristics of naive foals: lead changes and description of temporal and linear parameters. Equine Vet J Suppl, (34), 302–307.
Abstract: The selection of foals as future showjumpers remains a subjective process based on qualitative parameters; and hence, frequently suffers from disparity in the criteria used by experts in the field. A detailed biomechanical description of foals while jumping would be most helpful in providing a better basis for the accurate assessment of their future athletic ability. The Qualisys Pro Reflex system was used to capture 3-dimensional kinematics of 41 Dutch Warmblood foals age 6 months free jumping a vertical fence, preceded by a cross pole fence. The left lead was the most preferred lead for both the fore- and hindlimbs, from the landing following the cross poles to the first move-off stride after clearing the vertical fence. The foals displayed a high incidence of rotary gallop during both the jump stride (divided into take-off, jump suspension and landing) and the first move-off stride, while change of lead was frequently observed during jump suspension. At the take-off side of the fence, the trailing forelimb in the last approach stride was placed furthest from the fence, whereas the trailing hindlimb at take-off was placed closest (P<0.05). At the landing side, the trailing forelimb was the closest and the leading hindlimb of the move-off stride 1 was the furthest (P<0.05). The trailing forelimb in the approach stride 1 had a significantly longer stance phase duration than the leading forelimb. At landing, the leading forelimb stance phase lasted longer than that of the trailing forelimb (P<0.05). The hindlimbs did not differ in their stance phase duration at take-off. The height reached by the hooves above the fence top was significantly greater in the hind limbs (P<0.05). In addition, the hindlimbs (97.1 +/- 2.6%) shortened more than the forelimbs (92.6 +/- 5.7%) (P<0.05). It is concluded that the overall jumping technique of foals is similar to that reported in literature for mature horses. If the patterns are consistent throughout the rearing period, the quantitative analysis of the kinematics of free jumping foals may provide a valid quantitative basis for early selection.
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Meershoek, L. S., Schamhardt, H. C., Roepstorff, L., & Johnston, C. (2001). Forelimb tendon loading during jump landings and the influence of fence height. Equine Vet J Suppl, (33), 6–10.
Abstract: Lameness in athletic horses is often caused by forelimb tendon injuries, especially in the interosseus tendon (TI) and superficial digital flexor tendon (SDF), but also in the accessory ligament (AL) of the deep digital flexor tendon (DDF). In an attempt to explain the aetiology of these injuries, the present study investigated the loading of the tendons during landing after a jump. In jumping horses, the highest forces can be expected in the trailing limb during landing. Therefore, landing kinematics and ground reaction forces of the trailing forelimb were measured from 6 horses jumping single fences with low to medium heights of 0.80, 1.00 and 1.20 m. The tendon forces were calculated using inverse dynamics and an in vitro model of the lower forelimb. Calculated peak forces in the TI, SDF and DDF + AL during landing were 15.8, 13.9 and 11.7 kN respectively. The relative loading of the tendons (landing forces compared with failure forces determined in a separate study) increased from DDF to TI to SDF and was very high in SDF. This explains the low injury incidence of the DDF and the high injury incidence of the SDF. Fence height substantially influenced SDF forces, whereas it hardly influenced TI forces and did not influence AL strain. Reduction of fence height might therefore limit the risks for SDF injuries, but not for TI and AL injuries.
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Barrey, E., & Galloux, P. (1997). Analysis of the equine jumping technique by accelerometry. Equine Vet J Suppl, (23), 45–49.
Abstract: The purpose of this study was to demonstrate the relationships between jumping technique and dorsoventral acceleration measured at the sternum. Eight saddle horses of various jumping abilities competed on a selective experimental show jumping course including 14 obstacles. An accelerometric belt fastened onto the thorax continuously measured the dorsoventral acceleration during the course. At each jump, 11 locomotor parameters (acceleration peaks, durations and stride frequency) were obtained from the dorsoventral acceleration-time curves. The type of obstacle significantly influenced the hindlimb acceleration peak at take-off and the landing acceleration peak (P<0.01). The poor jumpers exhibited a higher mean forelimb acceleration peak at take-off, a higher forelimb/hindlimb ratio between peaks of acceleration (F/H), and a lower approach stride frequency than good jumpers. Knocking over an obstacle was significantly associated with a low hindlimb acceleration peak at take-off and a high F/H ratio (P<0.01). In order to observe the continuous changes in the frequency domain of the dorsoventral acceleration during the approach and take-off phase, a Morlet's wavelet analysis was computed for each horse jumping over a series of 3 vertical obstacles. Different patterns of time-frequency images obtained by wavelet analysis were found when the horse either knocked over a vertical obstacle or cleared it. In the latter case, the image pattern showed an instantaneous increase in stride frequency at the end of the approach phase, and a marked energy content in the middle frequency range at take-off.
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Galloux, P., & Barrey, E. (1997). Components of the total kinetic moment in jumping horses. Equine Vet J Suppl, (23), 41–44.
Abstract: Thirty horses were filmed with a panning camera operating at 50 frames/s as they jumped over a 1.20 x 1.20 m fence. The markers of 9 joints on the horse and 7 joints on the rider were tracked in 2D with the TrackEye system. The centre of gravity and moment of inertia of each segment were calculated using a geometric algorithm and a cylindric model, respectively. The kinetic moment of each part of the horse was calculated after filtering, and resampling of data. This method showed the relative contribution of each body segment to the body overall rotation during the take-off, jump and landing phases. It was found that the trunk, hindlimbs and head-neck had the greatest influence. The coordination between the motion of the body segments allowed the horse to control its angular speed of rotation over the fence. This remained nearly constant during the airborne phase (120 +/- 5 degrees/s). During the airborne phase, the kinetic moment was constant because its value was equal to the moment of the external forces (722 +/- 125 kg x m2/s).
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Robert, C., Valette, J. P., & Denoix, J. M. (2006). Correlation between routine radiographic findings and early racing career in French trotters. Equine Vet J Suppl, (36), 473–478.
Abstract: REASONS FOR PERFORMING STUDY: The relationship between the presence of radiological abnormalities and subsequent racing performance is controversial. However, as training is expensive and time consuming, it would save time and money to identify subjects with osteo-articular lesions not compatible with a normal racing career on the basis of routine radiographic screenings at yearling age. OBJECTIVES: To evaluate the impact of osteo-articular lesions on racing ability in French Trotters and identify radiographic changes associated with failure in 'qualification', in order to provide objective criteria for selection of horses based on their osteo-articular status. HYPOTHESIS: The influence of radiographic findings (RF) on racing ability depends on their nature, location, clinical relevance and number. METHODS: The limbs of 202 French Trotters were radiographed just before they started training. All the RF were graded according to a standardised protocol depending on their severity. The success in 'qualification' (first race in career of French Trotters) was the criteria used to assess racing ability. Breeders and trainers were questioned about the causes for horses not racing. RESULTS: Overall 113 (55.9%) horses qualified. Osteoarticular lesions were directly responsible for nonqualification in 31% of the horses. Subjects with more than one abnormal RF, with abnormal RF on the fore-, hind-fetlock or proximal tarsus were less likely to qualify. Dorsal modelling in the front fetlock and osteochondrosis of the lateral trochlear ridge of the femur also significantly reduced the qualification rate. CONCLUSIONS: Most RF are compatible with beginning a racing career, but severe RF or multiple abnormal RF significantly compromise future racing career. POTENTIAL RELEVANCE: This study supports the use of routine radiographic programmes for detection of osteoarticular lesions in yearlings. A synthetic radiographic score, based on both the severity and the number of lesions, could be useful for breeders and trainers as complementary information to select their horses.
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Takahashi, T., Kasashima, Y., Eto, D., Mukai, K., & Hiraga, A. (2006). Effect of uphill exercise on equine superficial digital flexor tendon forces at trot and canter. Equine Vet J Suppl, (36), 435–439.
Abstract: REASONS FOR PERFORMING STUDY: One cause of overstrain injury to the superficial digital flexor tendon (SDFT) in horses is the force loaded on the SDFT during repeated running. Therefore, decreasing this force may reduce SDFT injury. It has been reported that strain on the SDFT decreases with a toe-wedge shoe. Uphill courses are used for training of racehorses, and the angle of hoof-sole to the horizon during uphill running is similar to that of the toe-wedge shoe. OBJECTIVES: To determine the effects of uphill exercise on the force on the SDFT during trotting and cantering. METHODS: Arthroscopically implantable force probes (AIFP) were implanted into the SDFT of the left or right forelimb of 7 Thoroughbred horses and AIFP output recorded during trotting and cantering on a treadmill inclined at slopes of 0, 3 or 8%, and then 0% again. Superficial digital flexor tendon force was calculated as a relative value, with the amplitude of AIFP output voltage at initial 0% slope equal to 100. RESULTS: Out of 14 sets of experiments, AIFP data were analysed successfully in 9 at the trot, in 3 at the canter in the trailing forelimb on a slope of 3 and 8%, and in 2 at the canter in the leading forelimb on a slope of 3%. Increasing the incline from 0-8% tended to decrease peak force in the SDFT at the trot, and in the trailing forelimb at the canter. However, force in the SDFT was unchanged in the leading forelimb at the canter on the 3% incline. CONCLUSIONS: The force in the SDFT trotting or cantering uphill is unchanged or lower than that loaded at the same speed on a flat surface. Because at similar speeds the workload for uphill exercise is greater than on the flat, uphill running increases exercise intensity without increasing force in the SDFT. POTENTIAL RELEVANCE: Uphill exercise may reduce the risk of SDFT injury as both running speed and SDFT force are decreased on an incline as compared to the flat, even when exercise intensity is the same. Further study is needed to confirm these findings at canter in a larger population of horses.
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Peel, J. A., Peel, M. B., & Davies, H. M. S. (2006). The effect of gallop training on hoof angle in thoroughbred racehorses. Equine Vet J Suppl, (36), 431–434.
Abstract: REASONS FOR PERFORMING STUDY: The economic impact of soundness problems in racehorses is very high and low hoof angle at the toe has been associated with a lack of soundness. However, it is not clear what environmental and management factors might contribute to a low hoof angle. OBJECTIVES: To investigate the hypothesis that the hooves of racehorses become flatter when in gallop training, as well as to determine factors contributing to this trend. METHODS: Weekly hoof measurements were taken with a hoof gauge from 45 Thoroughbred racehorses; 4 Thoroughbred show horses kept in consistent conditions and shod by the same farrier as some of the racehorses; and 6 unshod free-ranging horses. A further 15 horses were measured twice in one day to determine the repeatability of the method. RESULTS: Repeatability coefficients were 0.31 degrees for the left hoof and 0.37 degrees for the right. Racehorses in training showed a significant decrease in hoof angle over time while free ranging horses and show horses did not. Free-ranging horses had a significantly lower angle in winter (wet) compared with summer (dry) in both left (P = 0.040) and right (P = 0.017). Show horses had no significant change in hoof angle. Racehorses that had a period of rest during the experiment (n = 11) showed a decrease in hoof angle during training and an increase over their rest period for both hooves (P = 0.005 for the left hoof, P = 0.0009 for the right). CONCLUSIONS: Training for fast exercise in Thoroughbred racehorses is associated with a reduction in hoof angle and wet pasture conditions may also be associated with a reduced hoof angle in free-ranging horses. Potential relevance: Gallop exercise has a potentially large effect on hoof angle and therefore, a change in angle should be expected to occur in racehorses starting fast exercise work. Hence management of horses with abnormally low hoof angles may require an adaptation to their training regime in order to minimise this effect.
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Winkelmayr, B., Peham, C., Fruhwirth, B., Licka, T., & Scheidl, M. (2006). Evaluation of the force acting on the back of the horse with an English saddle and a side saddle at walk, trot and canter. Equine Vet J Suppl, (36), 406–410.
Abstract: REASONS FOR PERFORMING STUDY: Force transmission under an English saddle (ES) at walk, trot and canter is commonly evaluated, but the influence of a side saddle (SS) on the equine back has not been documented. HYPOTHESIS: Force transmission under a SS, with its asymmetric construction, is different from an ES in walk, trot and canter, expressed in maximum overall force (MOF), force in the quarters of the saddle mat, and centre of pressure (COP). The biomechanics of the equine back are different under a SS compared to ES. METHODS: Thirteen horses without clinical signs of back pain ridden in an indoor riding school with both saddles were measured using an electronic saddle sensor pad. Synchronous kinematic measurements were carried out with tracing markers placed along the back in front of (withers, W) and behind the saddle (4th lumbar vertebra, L4). At least 6 motion cycles at walk, trot and canter with both saddles (ES, SS) were measured. Out of the pressure distribution the maximum overall force (MOF) and the location of the centre of pressure (COP) were calculated. RESULTS: Under the SS the centre of pressure was located to the right of the median and slightly caudal compared to the COP under the ES in all gaits. The MOF was significantly different (P<0.01) between saddles. At walk, L4 showed significantly larger (P<0.01) vertical excursions under the ES. Under the SS relative horizontal movement of W was significantly reduced (P<0.01) at trot, and at canter the transversal movement was significantly reduced (P<0.01) . In both trot and canter, no significant differences in the movement of L4 were documented. CONCLUSIONS AND POTENTIAL RELEVANCE: The results demonstrate that the load under a SS creates asymmetric force transmission under the saddle, and also influences back movement. To change the load distribution on the back of horses with potential back pain and as a training variation, a combination of both riding styles is suitable.
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