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Topic:Athletic Horses
The topic of athletic horses encompasses the study and analysis of horses that are trained and conditioned for performance in various disciplines such as racing, show jumping, dressage, and eventing. These horses are subject to specialized training regimens and nutritional plans to optimize their physical capabilities and performance outcomes. Research in this area often focuses on aspects such as biomechanics, cardiovascular fitness, muscle physiology, and injury prevention. This topic includes a collection of peer-reviewed research studies and scholarly articles that explore the physiological adaptations, training methodologies, and health management practices associated with maintaining and enhancing the performance of athletic horses.
Muscular and metabolic responses to moderate-intensity short-term training. The objectives of this study were to determine the effects of 10 consecutive days of moderate-intensity training on 1) the muscular metabolic response to exercise at 100% of the pre-training maximum rate of oxygen consumption (VO2max); and 2) mitochondrial enzyme markers (citrate synthase, CS; succinate dehydrogenase, SDH; 3-hydroxy-acyl-CoA dehydrogenase, HAD) of oxidative capacity in middle gluteal muscle. Six mature, unfit Thoroughbred horses completed both incremental (for determination of VO2max) and high-intensity exercise protocols before (HI1) and after (HI2) training. Training consist...
Relationship between VO2max, heart score and echocardiographic measurements obtained at rest and immediately following maximal exercise in thoroughbred horses. We evaluated the relationships of heart score (HS) and echocardiographic measures to maximal oxygen consumption (VO2max), maximal cardiac output (Qmax), and maximal stroke volume (SVmax). Six fit, mature Thoroughbred horses weighing (mean +/- s.e.) 487 +/- 11 kg were run 4 times on an inclined (10%) treadmill. Each run consisted of a 3 min warm-up at 4 m/s followed by completion of an incremental exercise test in which each horse ran until VO2max was reached. Arterial and mixed venous blood was collected to determine arteriovenous oxygen content difference C(a-v)O2[ in the last 15 s of exercis...
Effects of conditioning horses with lactate-guided exercise on muscle glycogen content. The effects of 3 different conditioning programmes on muscle glycogen concentration in horses were examined. Speed of exercise was selected according to the blood lactate values for each horse derived from a standardised exercise test before beginning a conditioning programme. Six 2-year-old Haflinger stallions were assigned randomly to one of 3 conditioning programmes according to a 6 x 3 latin square design: 45 min at their individual v1.5 or v2.5 and 25 min at v4. Each conditioning programme lasted 6 weeks (21 exercise sessions), followed by 5 weeks without conditioning (resting period). Al...
Skeletal myosin heavy chain composition and carriage training. Three different myosin heavy chain (MHC) isoforms have been identified in the equine gluteus medius muscle: the slow or MHC-I and the 2 fast MHC-IIA and MHC-IIX isoforms. They are distributed in 3 fibre types containing a single MHC (I, IIA, IIX) and 2 hybrid types co-expressing 2 isoforms (I + IIA, IIA + IIX). The aim of this study was to determine if heavy carriage training alters skeletal MHC composition in horses. Fourteen Andalusian mares age 42-46 months were used. Seven horses were used as controls to estimate the effects of growth on muscle. The remaining 7 horses underwent a training ...
Environmental stress and 3-day eventing: effects of altitude. Three-day event horses are subject to various external environmental stresses including changes in ambient temperature, humidity, altitude, and test severity. Considerable research on the adverse effects of increased heat and humidity preceded the 1996 Olympic Summer Games in Atlanta, Georgia USA, but no research has been done previously on the effects of altitude on 3-day eventing. Physical and venous blood gas data were collected on horses (n = 24) competing in the High Prairie Preliminary (CCN*) and Intermediate (CCN**) 3-day events and Preliminary Horse Trials in Parker, Colorado (1900 m a...
Frusemide and weight carriage alter the acid:base responses of horses to incremental and to brief intense exertion. We speculated that frusemide would attenuate the acidosis associated with intense exertion, and that weight carriage would mitigate this effect. Therefore, in each of 2 experiments we measured pulmonary artery and systemic arterial blood pH, PCO2, PO2 and pulmonary artery temperature in 9 horses during exertion on a treadmill after each of 3 treatments. The treatments were: 1) injection of saline solution (C), 2) injection of frusemide (1 mg/kg bwt, i.v. 4 h before running) (FU) and 3) injection of frusemide (F) as for FU and the horses carried weight equal to that lost in the 4 h after frusem...
Effect of exercise on bone density in distal regions of the equine third metacarpal bone in 2-year-old thoroughbreds. The present study addressed the question of whether training induces changes in bone density in the younger racehorse in regions relevant to the genesis of the common sagittal condylar fracture pattern and, if so, the nature of such alteration. Third metacarpal bones (McIII) were obtained from 12 experimental Thoroughbred, unbroken fillies, age 18.1-21.0 months at entry to the study. Six (Group E) undertook 19 weeks of progressive high intensity exercise on a high-speed treadmill at 3% incline. Six (Group C) walked 40 min each day. Clinical bone density was studied by Computed Tomography (CT) ...
Hyperbolic relationship between time-to-fatigue and workload. The power:time-to-fatigue relationship for high-intensity exercise in man is useful in determining anaerobic work capacity. The purpose of this study was to determine the nature of this relationship in horses. Eight Standardbred horses performed 5 or 6 run-to-fatigue trials on a treadmill. Exercise intensities were chosen to induce fatigue in 30 to 240 s. The order of trials was randomised for each horse, but balanced overall for the first 4 trials. The data for power (independent variable) and time-to-fatigue (dependent variable) were tested for goodness of fit to hyperbolic, linear and expon...
Pulmonary vascular resistance of horses decreases with moderate exercise and remains unchanged as workload is increased to maximal exercise. This study was carried out to examine changes in pulmonary vascular resistance (PVR) induced by moderate and strenuous exercise; the objective being to understand why pulmonary artery blood pressure of exercising horses increases progressively as work intensity increases. Pulmonary arterial and wedge pressures (referenced at the point of the left shoulder) were determined simultaneously with cardiac output in 2 groups of healthy, sound, exercise-trained horses. Horses in Group 1 (n = 8) were studied at rest and during exercise performed at 8 and 13 m/s; the latter workload eliciting maximal he...
Should equine athletes commence training during skeletal development?: changes in tendon matrix associated with development, ageing, function and exercise. In human athletes, conditioning, training and competition are commenced before skeletal maturity. Yet in equine athletics, racing of young (age 2 years) horses remains contentious. Tendon injury persists as major causes of wastage in equine athletes. Minimising injury and associated welfare issues could involve a radical approach to the timing and implementation of conditioning and training. Tendons were examined from Thoroughbreds, Dutch Warmblood foals, working horses and also a group of wild horses to evaluate effects of age, function and exercise. Gross mechanical properties did not differ...
Comparison of exercise variables measured during intensity of simulated training to variables at maximal effort in standardbreds. The heart rate changes during routine training in a group of 8 actively racing Standardbreds were used to simulate the training work on a treadmill (ST) and indices of exercise compared to maximal effort (MAX) on the treadmill. The following parameters were recorded during treadmill work: heart rate, velocity, O2 consumption, respiratory and stride frequency, and stride length. Blood lactate concentrations were measured before and after each work test. Heart rate during simulated training was mean +/- s.d. 87.8 +/- 5.5% heart rate in MAX, one of the 8 horses working 0.05), being higher during...
Haematological and biochemical responses to training and overtraining. We sought a physiological marker of overtraining in horses, using commonly practised field and laboratory tests to allow early prediction and treatment of the syndrome. Thirteen Standardbred horses were trained as follows: phase 1 (endurance, 7 weeks), phase 2 (high intensity, 9 weeks) and phase 3 (overload, 18 weeks). In phase 3 the horses were divided into 2 groups: overload training (OLT) and control (C). The OLT group exercised at greater intensities, frequencies and durations than the C group. Overtraining occurred after 31 weeks and was defined as a significant decrease in treadmill run ...
Electrolyte and glycerol supplementation improve water intake by horses performing a simulated 60 km endurance ride. To replace electrolytes lost in sweat during endurance competitions, riders frequently supplement horses with hypertonic oral electrolyte pastes. To determine whether this practice and concurrent administration of the so-called hyperhydrating substance glycerol are of benefit, weight loss, voluntary water intake, plasma osmolality, and plasma protein and electrolyte concentrations were measured in 6 Arabian horses supplemented with a total of 2.4 ml/kg bwt of water (W); 0.2 g/kg bwt KCl and 0.4 g/kg bwt NaCl in 2.4 ml/kg bwt of water (E); or 0.2 g/kg bwt KCl and 0.4 g/kg bwt NaCl in 2.4 ml/kg ...
Influence of frusemide on dynamic cardiac variables during exercise. Exercising horses have extremely high right and left atrial pressures. Limitation in ventricular function (i.e. relaxation) may play a role in these high pressures. We studied relaxation characteristics of the right ventricular myocardium and the impact of frusemide (2.0 mg/kg bwt i.v.) on these characteristics in horses exercising at 8, 10, 12 and 14 m/s. Exercise tests were performed 4 h after administration of frusemide. Right ventricular (RV) pressure was analysed using Fast Fourier Transform techniques to remove non cardiac components of the pressure signal. Mean right atrial (RA) pressur...
Maximal exercise transiently disrupts hormonal secretory patterns in standardbred geldings. Basal concentrations of cortisol (CORT), beta-endorphin (beta EP), growth hormone (GH) and testosterone (T) and their disruption during 32 h of recovery after treadmill exercise were investigated in 4 geldings. Blood samples were collected from resting horses every 20 min between 0600-1000 and 1500-1900 h, and hourly between 1000-1500 h on 3 consecutive days. Treadmill exercise tests comprising 2 min intervals at 30, 50, and 70% VO2max then to fatigue at 100% VO2max were conducted between 1020-1130 h on Day 2. Blood was collected before, during and 15, 30, 60 and 90 min after exercise. Mean (C...
Effects of low- and moderate-intensity training on metabolic responses to exercise in thoroughbreds. This experiment was undertaken to determine whether there were differences in cardiorespiratory, haematological and muscular responses in horses trained at either low or moderate intensities. Ten Thoroughbred horses previously rested in paddocks for 4 months were trained 5 days/week for 9 weeks. Horses were allocated randomly into fast or slow groups and exercised the same distance each day. Training distances were 1600 m in Weeks 0 and 1 up to 4000 m in Week 9. The fast group were trained at an intensity inducing a post training blood lactate of 4-8 mmol/l. This intensity was determined for e...
Forelimb kinematics and net joint moments during the swing phase of the trot. The purpose of this study was to calculate net moments of force at the joints of the forelimb during the swing phase of the stride. An optoelectronic system was used to measure segmental kinematics for 3 strides in 5 sound, Warmblood horses trotting at a mean velocity +/- s.d. of 3.03 +/- 0.16 m/s. A link segment model was used to determine the net moments of force about the joints of the left forelimb. The model combined kinematic data with morphometric data describing the inertial parameters of the limb segments of warmblood horses, and incorporated correction factors for skin displacement. ...
Influence of girth strap tensions on athletic performance of racehorses. Eight horses were exercised at speeds to produce 80% of maximal heart rates, on 4 occasions using a randomised block design, and girthed at tensions of approximately 5, 10, 15 or 20 kg using a standard canvas girth attached to a racing saddle. Tension was recorded continuously using an in-line load cell connected to a physiograph. Horses ran until fatigued on a treadmill inclined at 10% slope. Tensions were measured at peak inhalation (T/inh) and exhalation (T/exh), recorded at rest (rest) and during exercise (ex). Data were analysed by ANOVA and, in addition, least squares linear regression w...
Fragility of red cells during exercise is affected by blood pH and temperature. We examined the relationship in horses between osmotic fragility of erythrocytes (OFE) measured as the red cell haemolysis rates (HLR) in 0.56% NaCl and certain physiological characters. Animals were exercised on a treadmill: warmed up at 30% VO2max for 5 min or at 105% VO2max for 1 min, given an exercise test at 80 or 105% VO2max until fatigued, and then cooled down. The pH and temperature of the blood had a significant correlation for the HLR: r = 0.93 and 0.92 (P < 0.01) on arterial and mixed venous blood, respectively. In multiple regression analysis, heart rate and packed cell volume s...
The effect of training on the calcified zone of equine middle carpal articular cartilage. Carpal osteochondral injury is frequently observed in strenuously trained horses. It is clear that the integrity of articular cartilage and subchondral bone are intimately related, although there is controversy about which component is the most important. Calcified cartilage provides the mechanical link between soft hyaline cartilage and stiff subchondral bone so it is essential to understand the tissue's response to exercise. Middle carpal calcified and uncalcified (hyaline) cartilage thickness was investigated in horses undergoing high- and low-intensity exercise. Twelve untrained horses (18...
Temporal changes in the trot between the first and third horse inspections at a CCI*** 3-day event. Kinematic parameters were measured from horses competing in a CCI*** 3-day event. The horses were filmed during the first and third horse inspection. This provided a repeat sample on 16 horses. The horses were filmed using a panning lateral S-VHS video camera (50 Hz). Spatial measurements were taken for mean +/- s.d. 5.66 +/- 0.92 strides for the first inspection and 5.05 +/- 1.27 for the third inspection. Within the calibration zone, data of the horses accelerating and obtaining a constant velocity were collected. The horses trotted with a higher mean velocity during the third inspection (0.2...
Effects of phlebotomy and autologous blood transfusion on oxygen transport in the racehorse. Because the haemoglobin concentration Hb[ during exercise may be at the upper limit of blood viscosity for effective oxygen delivery, we hypothesised that administration of blood would not further enhance oxygen delivery or exercise capacity. Six Thoroughbred geldings were used in 5 incremental treadmill exercise tests over a period of 4 weeks. The first test was performed 6 days prior to phlebotomy, which involved the removal of 20 ml/kg bwt of venous blood. Exercise tests were performed at 1, 8 and 15 days after blood removal. Six days after the 15 day post phlebotomy exercise test, blood fr...
Racing performance in red blood cell hypervolaemic standardbred trotters. The association between red blood cell hypervolaemia (RCHV) and racing performance was examined in 116 Standardbred trotters referred to the clinic during a 5 year period with histories of impaired racing performance. Red cell hypervolaemia was the only significant abnormality detected in a thorough clinical examination, cell volumes ranging 116-178% of the predicted normal values. They were also compared with the performance traits of the contemporary Swedish Standardbred trotter population (n = 58,058). The performance traits were based on earnings per year and start, best annual racing time...
Biomechanical analysis of horse shoeing. Most of the principles of farriery have been derived from practical experience and traditional skills of individual farriers. To date, there has been little done in the way of good science and few publications have appeared to advance the discipline. Therefore, opinions or policies on horse shoeing vary greatly between farriers and members of the veterinary profession. The aim of this workshop was to present the latest information on biomechanical analysis of horse shoeing as it relates to modern day farriery and could have direct benefits for the future of shoeing in performance horses.
Influence of rough track surfaces on components of vertical forces in cantering thoroughbred horses. No kinetic data are available to indicate the influence of a rough track surface and the resultant loss of footing on the components of hoof vertical forces. The aim of the present study was to evaluate the influence of rough track surfaces on the components of hoof vertical forces. Seven clinically sound 2-year-old Thoroughbred horses had instrumented shoes attached to both of the fore hooves to obtain the magnitudes of consecutive forces exerted in the hoof. All horses were cantered at approximately 10 m/s on straight tracks of smooth and rough surfaces of woodchip and dirt. The instrumented...
Thermoregulatory strategies during short-term exercise at different intensities. Previously we have observed a decline in sweating rate (SR) during high intensity exercise in an incremental test protocol. In man, the sweating sensitivity (SR/degree C) has been shown to vary with exercise intensity. The aim of the present study was to determine if thermoregulatory responses in the horse, a prolific sweater with a high rate of metabolic heat production, were modified by exercise intensity. The effect of 3 separate exercise intensities (50 (S), 70 (M) and 90% (F) VO2peak on neck (SRN) and gluteal sweating rate (SRG), pulmonary artery (TPA), rectal (TREC) and skin temperatures...
Is ventilation during maximal exercise limited by dynamic airway closure? A study was undertaken to find if the reason why horses hypoventilate when running is that they experience expiratory flow limitation due to dynamic airway closure. To test this hypothesis, we measured peak expiratory flows on a Thoroughbred galloping on a treadmill and hypoventilating and compared those flows with the peak dynamically-limited flow that the same horse could achieve during a forced expiratory flow-volume manoeuvre. At the approximate lung volumes at which the horse was ventilating while running, it did not appear to be mechanically limited and appeared to have reserve capacity ...
Comparison of some responses to exercise on the track and the treadmill in French trotters: determination of the optimal treadmill incline. The purpose of this study was to determine the optimal treadmill slope for trotters to produce the same heart rate and blood lactate responses as on the track during a standardized exercise test. Nine 2-year-old French trotters performed exercise tests on a training track and on a treadmill set at an incline of 0, 2 or 4%. For all horses, track testing was performed on day 1 and then on the treadmill according to a Latin-square design. The track test utilized three steps each of 3 min at speeds of 470, 530, 590 m/min and the same speeds were used on the treadmill. Derived physiological variabl...
Time of contact and step length: the effect of limb length, running speed, load carrying and incline. Using published values for twelve species of birds and mammals, we investigated the effects of limb length and running speed on time of contact and step length. In addition, we measured the time of contact in horses trotting up a 10 % incline and when carrying a load averaging 19 % of their body mass. From these values, we calculated stride period and step length. Our analysis of the interspecific data yielded the following relationship between time of contact (t(c) in s) and leg length (L in m) and running speed (v in m s(-)(1)): t(c)=0.80L(0.84)/v(0.87) (r(2)=0.97). Both exponents in this re...
Outcome and racing performance after internal fixation of third and central tarsal bone slab fractures in horses. A review of 20 cases. Twenty horses with central and third tarsal bone slab fractures, were treated internal fixation. Eighteen of the 20 cases were Standardbred trotters, one was a Thoroughbred racehorse and one a Swedish Warmblood. The central tarsal bone (CT) was involved in 12 cases and the third tarsal bone (T3) in 8 cases. The fractures were treated by lag screw fixation with one (18 cases) or two (2 cases) 3.5 or 4.5 mm cortical screws. Horses were confined to stall rest for one month and then put on a gradually increasing exercise programme. Convalescence time was 3-8 months until the fracture had healed an...
