Exercise physiology in horses involves the study of the physiological responses and adaptations of horses to physical activity. This field examines how exercise impacts various systems in the equine body, including the cardiovascular, respiratory, muscular, and metabolic systems. Researchers focus on understanding how these systems interact during different types and intensities of exercise, and how they contribute to performance and recovery. Key areas of interest include the assessment of aerobic and anaerobic capacity, muscle fiber composition, energy metabolism, and thermoregulation. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms of exercise physiology in horses, with an emphasis on performance optimization, training regimens, and the prevention of exercise-related disorders.
De Graaf-Roelfsema E, Keizer HA, Wijnberg ID, Van Der Kolk JH.Gastric ulceration can be caused by different pathophysiological mechanisms including dietary factors, psychological stress and exercise. Overtraining is a medical syndrome in performance horses associated with altered hormone levels, altered feed intake, altered behaviour and decreased performance. These components might lead to a higher incidence of gastric ulceration in overtrained horses. Objective: To investigate whether the incidence of gastric ulceration is increased in overtrained compared to control horses. Methods: A longitudinal training study with twelve 1.5 years old Standardbred ...
Mukai K, Hiraga A, Takahashi T, Ohmura H, Jones JH.Several studies have indicated that even low-intensity warm-up increases O(2) transport kinetics and that high-intensity warm-up may not be needed in horses. However, conventional warm-up exercise for Thoroughbred races is more intense than those utilised in previous studies of equine warm-up responses. Objective: To test the hypothesis that warm-up exercise at different intensities alters the kinetics and total contribution of aerobic power to total metabolic power in subsequent supramaximal (sprint) exercise in Thoroughbred horses. Methods: Nine well-trained Thoroughbreds ran until fatigue a...
Foreman JH, Grubb TL, Inoue OJ, Banner SE, Ball KT.Objective blinded efficacy data during exercise are lacking on the use of single-dose i.v. nonsteroidal anti-inflammatory drugs (NSAIDs) before, during and after exercise. Objective: Single i.v. doses of either phenylbutazone (PBZ) or flunixin meglumine (FM) would prove more efficacious than negative saline control (SAL) before, during and after exercise in a reversible model of foot lameness. Methods: Six Quarter Horse mares had lameness induced by tightening a set screw against a heart bar shoe 1 h prior to treatment. Randomised blinded treatments included PBZ (4.4 mg/kg bwt i.v.), FM (1.1 m...
Noble P, Lejeune JP, Caudron I, Lejeune P, Collin B, Denoix JM, Serteyn D.Whereas the effect of heel configuration on the tension of the suspensory apparatus is well documented in the literature, there are few reports of joint contact force components in the equine distal forelimb. Objective: To improve understanding of the effect of heel configuration on equine digit joint loading, a sensitivity analysis was performed to compare the effect of a raised heel on joint contact force components in the coffin and fetlock joints during the stance phase of the trot. Methods: Four Warmblood horses were used. An inverse dynamic analysis was carried out using kinematic and ki...
Ely ER, Price JS, Smith RK, Wood JL, Verheyen KL.A previous study has identified exercise undertaken during training to be associated with racing performance in flat racehorses. However, no such studies have been conducted in National Hunt (NH) horses. Objective: To determine whether exercise undertaken during training is associated with racing performance in NH racehorses. Methods: Data were collected as part of a larger study investigating injury occurrence in NH racehorses. Race records and daily exercise data were obtained from NH racehorses at 14 training yards. Canter, gallop and race distances accumulated in the 30 days preceding a 'c...
McCutcheon LJ, Geor RJ.There is evidence that extensive training in cool conditions results in improvements to heat dissipation that contribute to successful acclimatisation. In horses, the effects of a less extensive training regimen have not been determined. Objective: This study investigated whether 10 consecutive days of moderate intensity treadmill training in cool conditions would improve thermoregulatory and sweating responses of horses to exercise in the heat. Methods: Six unfit Thoroughbred horses completed a standardised treadmill exercise test (SET) in hot, dry conditions (32-34 °C, 45-55% RH) before (SE...
Robert C, Goachet AG, Fraipont A, Votion DM, Van Erck E, Leclerc JL.Limited information exists about the physiological training-induced changes in electrolyte balance of horses competing in long distance endurance races. Objective: To determine the effects of endurance training and racing on hydration and electrolyte balance in horses. Methods: Blood and urine were sampled at rest in 8 endurance horses before training and after two 11 week training periods (T1 and T2). Each training was followed by a 120 km endurance ride and horses were sampled before, during and 2 h after the rides. Blood was analysed for packed cell volume (PCV), total protein (TP), urea, c...
Hill EW, Eivers SS, McGivney BA, Fonseca RG, Gu J, Smith NA, Browne JA, MacHugh DE, Katz LM.The role of molecular signalling pathways in the phenotypic adaptation of skeletal muscle to different exercise stimuli in the Thoroughbred horse has not been reported previously. Objective: To examine CKM, COX4I1, COX4I2 and PDK4 gene expression following high intensity sprint and moderate intensity treadmill exercise stimuli in skeletal muscle of Thoroughbred horses. Methods: Two groups of trained 3-year-old Thoroughbred horses participated. Group A (n = 6 females, n = 3 males) participated in an incremental step test (moderate intensity) to fatigue or HR(max) on a Sato high speed treadmill ...
Scott R, Nankervis K, Stringer C, Westcott K, Marlin D.Water treadmill exercise is often incorporated into rehabilitation programmes for horses yet little is known about the biomechanical and physiological responses to water walking. Objective: To establish whether stride frequency (SF) reached steady state as a result of 6 introductory water treadmill sessions and then to investigate the effect of increasing water height on SF, stride length (SL) and heart rate (HR). Methods: Nine horses with no previous experience of water treadmills completed 6 sessions of walking for between 15 and 30 min. Each horse was fitted with a leg mounted accelerometer...
Ohmura H, Mukai K, Takahashi T, Matsui A, Hiraga A, Jones JH.Accumulated O(2) deficit (AOD) and plasma lactate accumulation rate (PLAR) are alternative methods for estimating net anaerobic energy utilisation (NAEU) in exercising horses. How they compare or their accuracy is unknown. Objective: We hypothesised net anaerobic energy utilisation calculated by PLAR (NAUE(PLAR)) is equivalent to NAUE estimated by AOD (NAUE(AOD)). Methods: Six Thoroughbred horses ran at identical supramaximal speeds (118% aerobic capacity) until exhaustion for 2 runs while breathing normoxic (NO, 21% O(2)) or hyperoxic (HO, 26% O(2)) gas. Jugular blood was sampled at 15 s inte...
Revold T, Mykkänen AK, Karlström K, Ihler CF, Pösö AR, Essén-Gustavsson B.Muscular changes caused by training are breed-specific and studies on the Norwegian-Swedish Coldblooded Trotter (NSCT) are limited. Knowledge about lactate-transporters in muscle in this light draught breed used for harness racing is lacking. Objective: To identify muscular changes associated with training in young NSCTs and investigate muscular distribution of the monocarboxylate transporter 1 (MCT1) and its ancillary protein CD147, which facilitate lactate transport across membranes. Methods: Nine horses were followed from the start of their training period until the end of their 3-year-old ...
Goachet AG, Varloud M, Philippeau C, Julliand V.In endurance horses, commonly fed 80% forage, energy is provided mainly by VFA produced in the hindgut during cell wall degradation, but cell wall digestibility has been reported to be impaired by exercise. Objective: To assess the influence of a long-term endurance conditioning on cell wall digestion in horses. Methods: The total tract apparent digestibility of dry matter, organic matter and fibrous constituents, solid and liquid total mean retention time and the faecal microbial ecosystem of purebred Arabian horses were measured for 2 years in 2 longitudinal experiments. Methods: Performed a...
Fonseca RG, Kenny DA, Hill EW, Katz LM.Fitness assessment can be challenging. The use of global positioning systems (GPS) with heart rate (HR) monitors has been promising; however, evaluation of speed parameters during training has not been reported. Objective: To evaluate speed indices during training in Thoroughbreds using a GPS-HR monitor. Methods: Thoroughbreds (n = 102) were assessed during training with data collected each work day (WD; sprinting). Speed indices evaluated included maximal velocity (V(max)), duration at V(max) (V(maxt)), acceleration rate (m/s(2)) from 800 m to V(max) (Acc800-V(max)), the distance (m) 6 (V(max...
Essén-Gustavsson B, Connysson M, Jansson A.There is little information about the influence of crude protein (CP) intake on glycogen and free pool amino acid concentrations in the muscle of horses in training. High energy forage-only diets may be an alternative to concentrate rich diets and may provide high levels of CP. Objective: To study the effect of feeding 2 forage-only diets, containing either high or moderate CP concentrations on glycogen and free pool amino acid concentrations in the muscle. Methods: Two high energy forage-only diets based on high-energy grass forage were fed for 23 days in a crossover design to 6 Standardbred ...
Spooner HS, Nielsen BD, Schott HC, Harris PA.Excessive sweat loss during endurance exercise may lead to electrolyte disturbances and previous research suggests dietary factors may affect hydration status. While investigating the effect of dietary fibre type on hydration status, sweat samples were collected which allowed for the evaluation of sweat composition in horses consuming forage-based, low sodium (Na) rations. Objective: To investigate sweat composition in Arabian horses performing endurance type exercise while fed forage-based, rations low in Na. Methods: Six 2-year-old Arabian horses were fed, according to a replicated 3 × 3 La...
Stewart-Hunt L, Pratt-Phillips S, McCutcheon LJ, Geor RJ.Starch rich (S) feeds reduce insulin sensitivity in untrained horses when compared to high fat (F) feeds, but insulin sensitivity is not affected when S or F are fed during exercise training. The effects of S vs. F on training-associated alterations in skeletal muscle glucose metabolism are unknown. Objective: To determine the effects of dietary energy source on training-associated changes in insulin sensitivity, skeletal muscle GLUT4 protein and hexokinase (HK) and glycogen synthase (GS) activities in horses. Methods: After a baseline period on an all forage diet (Phase 1), horses were adapte...
Cottin F, Metayer N, Goachet AG, Julliand V, Slawinski J, Billat V, Barrey E.Arabian horses have morphological, muscular and metabolic features designed for endurance races. Their gas exchange and gait variables were therefore measured during a field exercise test. This study presents original respiratory and locomotor data recorded in endurance horses under field conditions. Objective: Respiratory gas exchange ratio (RER) of Arabian horses at the speed required to win endurance races (18 km/h for 120-160 km) are <1 and running economy (RE) is also low in order to maintain exercise intensity using aerobic metabolism for long intervals. The purpose of this study was to ...
Liburt NR, Adams AA, Betancourt A, Horohov DW, McKeever KH.Studies have demonstrated increases in mRNA expression for inflammatory cytokines following exercise in horses and have suggested those markers of inflammation may play a role in delayed onset muscle soreness. However, measurement of mRNA expression in white blood cells is an indirect method. No studies to date have documented the cytokine response to exercise directly in muscle in horses. Objective: This study tested the hypothesis that exercise increases cytokine markers of inflammation in blood and muscle. Methods: Blood and muscle biopsies were obtained from 4 healthy, unfit Standardbred m...
McKeever KH, Eaton TL, Geiser S, Kearns CF, Lehnhard RA.Older horses have an increased risk of hyperthermia due to impaired cardiovascular function. While many studies have investigated thermoregulation in horses during exercise, none have investigated the effects of ageing. Objective: To test the hypothesis that there is a difference in thermoregulation during exercise and plasma volume (PV) in young and old horses. Methods: Study 1: 6 young (Y, 7.7 ± 0.5 years) and 5 old (O, 26.0 ± 0.8 years) unfit Standardbred mares (507 ± 11 kg, mean ± s.e.) ran on a treadmill (6% grade, velocity calculated to generate a work rate of 1625 watts) until core ...
Rumpler B, Riha A, Licka T, Kotschwar A, Peham C.Weight boots are commonly used for Icelandic horses to increase the height of the flight arc of the forelimbs in toelt. Objective: To show the influence of weights and toelting speed on the height of the swing phase. Methods: Eight Icelandic horses (mean ± s.d. 12 ± 3 years old, 369 ± 46 kg) were used. Reflecting makers were placed on the dorsal side of each hoof. The motion was collected with a kinematic system (10 cameras, 120 Hz sample rate, 1.3 Mpixels resolution). The horses were ridden in toelt by 2 experienced riders on a treadmill at 2 different speeds (2.96 m/s ± 0.30 and 4.10 m/s...
Lejeune JP, Sandersen C, Votion D, Caudron I, Vander Heyden L, Franck T, Ceusters J, Mouithys-Mickalad A, Niesten A, De La Rebière de Pouyade G....Intensive exercise induces a systemic inflammatory response characterised by an increase of blood neutrophil count and myeloperoxidase (MPO) release. Neutrophil elastase (NE) could also contribute to tissues lesions by its proteinase activities. Objective: To compare plasmatic NE concentrations before and after different forms of intensive exercise. Methods: EDTA blood samples were taken from 51 eventing horses (EvH) and 32 endurance horses (EndH) were sampled before the race (T0). Blood sampling was performed 2 h (T1) after completing either phase D of a one or 2 star eventing competition (n ...
Buhl R, Meldgaard C, Barbesgaard L.Electrocardiographic reference values of clinically normal horses during exercise are a prerequisite when evaluating horses with poor performance or horses presented with cardiac abnormalities (e.g. valvular regurgitation). No published studies have reported cardiac rhythms of clinically normal showjumping horses. Objective: To demonstrate the feasibility of obtaining exercise electrocardiogram (ECG) in normal horses during showjumping and also to document the prevalence and frequency of arrhythmias in association with exercise. Methods: Thirty-four healthy showjumping horses aged 4-13 years (...
Borgia LA, Valberg SJ, Essen-Gustavsson B.Flexor tendon injury may be due to flexor muscle fatigue, contributing to fetlock joint hyperextension and tendon damage. A water treadmill provides resistance training on flexor tendon muscles, which might reduce the risk of tendon injury. Objective: To determine the effect of water treadmill training on the properties of the gluteal and superficial digital flexor (SDF) muscles and on cardiocirculatory response to a standardised exercise test. Methods: Five healthy unfit horses were trained on a water treadmill for 5 days/week for 4 weeks, starting with 5 min/day increasing to 20 min/day. Bef...
Colahan PT, Jackson CA, Rice B, Szabo N, Jones JH.Sildenafil, a phosphodiesterase-5 inhibitor vasodilator, increases cGMP concentrations by inhibiting enzymatic degradation. Marketed to treat erectile dysfunction in men, it also reduces pulmonary arterial pressure (PAP). Because it reduces PAP, sildenafil may enhance performance and/or prevent exercise induced-pulmonary haemorrhage (EIPH). Objective: To determine if sildenafil citrate administration altered commonly measured indices of performance or reduced EIPH in exercised horses. Methods: Thirteen athletically conditioned Thoroughbred horses (2 mares and 11 geldings, age 3-12 years) were ...
Kallings P, Persson SG, Essén-Gustavsson B.Since nonsteroidal anti-inflammatory drugs, such as flunixin, on account of their anti-inflammatory and analgesic properties, are used in both racing and equestrian sport horses, the question has been raised as to whether these drugs affect the physiological responses to exercise and thus performance potential. Objective: The aims of this investigation were to study the effects of flunixin on cardiorespiratory, metabolic and locomotor parameters in horses during intense treadmill exercise. Methods: Six Standardbred trotters underwent an incremental treadmill exercise test to fatigue, without d...
Nagy A, Murray JK, Dyson S.Endurance is the fastest growing Féderation Équestre International (FEI) discipline and the large number of eliminations on veterinary grounds needs to be investigated. Objective: To document elimination rates and explore potential risk factors for elimination due to lameness or metabolic reasons in 9 countries representing 5 continents. Methods: Data for rides of ≥ 100 km ('elite endurance rides') in Australia, France, Italy, South Africa, Spain, United Arab Emirates (UAE), UK, Uruguay and USA were collected from the FEI website. Data were collected for all started horses on the country, ...
Franck T, Votion DM, Ceusters J, De La Rebière de Pouyade G, Mouithys-Mickalad A, Niesten A, Fraipont A, VAN Erck E, Goachet AG, Robert C, Serteyn D.Intense exercise in horses induces an increase of creatine kinase (CK) and stimulation of neutrophils which release the strong oxidant enzyme, myeloperoxidase (MPO) into the blood. It is not known whether active MPO is found in equine muscles and whether oxidant activity of neutrophils could affect muscular tissues and mitochondrial activity. Objective: Specific immuno-extraction followed by enzymatic detection (SIEFED) methods will be employed for the first time to assess both the normal range of MPO and mitochondrial complex I (MCI) activities in equine muscular microbiopsies and to study th...
Muñoz A, Riber C, Trigo P, Castejón-Riber C, Castejón FM.Limited information exists concerning the defence of homeostasis during endurance competitions and the relationship with performance. Objective: This research analysed renin (REN), angiotensin II (ANG), aldosterone (ALD) and vasopressin (AVP) in horses covering different distances, assesses differences between successful and eliminated horses and evaluates correlations between hydration status, renal function, electrolytes, REN, ANG, ALD and AVP. Methods: Packed cell volume (PCV), velocity and serum concentrations of REN, ANG, ALD, AVP, Na, K, Cl, Ca, Mg, P, creatine kinase, aspartate aminotra...
Bergh A, Nordlöf H, Essén-Gustavsson B.Neuromuscular electrical stimulation (NMES) is used to increase or maintain muscle strength during rehabilitation. Human studies investigating different protocols show that some treatments induce changes in muscle characteristics. Despite the frequent use of NMES in horses, no studies have been published describing its efficacy. Objective: To investigate the effects of a NMES protocol on equine fibre types and areas, glycogen concentrations and enzyme activities. Methods: NMES was administrated to m. gluteus medius and m. longissimus dorsi, on one side of 6 healthy Standardbred horses. The con...
Zsoldos RR, Kotschwar AB, Kotschwar A, Groesel M, Licka T, Peham C.Skeletal muscle activity can be concentric or eccentric, anisometric or isometric and correlation of the equine splenius muscle activity with the movement of its effector joints at walk and trot has not yet been fully characterised. Objective: Investigating activity of the splenius muscle together with kinematics of head and cranial neck at walk and trot. Methods: Kinematics and surface electromyography were measured in 6 horses (8-20-years-old, 450-700 kg) without signs of neck pain. Markers were placed on left and right crista facialis, and on left and right cervical vertebrae 1 and 3. Head ...
Essén-Gustavsson B, Karlström K, Lindholm A.Venous blood samples and middle gluteal muscle biopsies were obtained from 21 horses taking part in 100 km or 50 km endurance rides. Group A consisted of seven horses competing over 100 km (four horses completed the ride). Group B consisted of the six horses that were among the 10 best over 50 km while the other eight horses of Group C completed 50 km at a slower speed. Blood lactate, glycerol and creatine kinase increased in all groups while aspartate aminotransferase levels were higher only in Group A. No changes was found in blood glucose in Groups B and C while horses in Group A had lower ...
Rose RJ, Allen JR, Hodgson DR, Stewart JH, Chan W.Four standardbred horses with subcutaneously relocated carotid arteries were given a seven week training programme of treadmill exercise at a gradient of 19 per cent in order to assess if there were any effects of exercise and training on haematology, arterial blood gas and acid base measurements, plasma biochemistry and heart rate. The exercise consisted of one minute walking at 110 metres/minute followed by five minutes trotting at 200 metres/minute, twice daily in the first week. The period of trotting exercise was increased by one minute per week so that by the seventh week the horses were...
Manohar M, Goetz TE.The present study examined whether Thoroughbred horses performing strenuous exercise exhibit intrapulmonary arteriovenous shunting that may contribute to the observed arterial hypoxemia. Experiments were carried out on seven healthy, exercise-trained Thoroughbreds at rest, maximal exercise (galloping at 14 m/s on a 3.5% uphill grade for 120 s), and submaximal exertion (8 m/s on a 3.5% uphill grade for 150 s). Along with blood gas/hemodynamic parameters, intrapulmonary arteriovenous shunting was studied by injecting 15-microm-diameter microspheres, labeled with different stable isotopes, into t...
Erickson BK, Seaman J, Kubo K, Hiraga A, Kai M, Yamaya Y, Wagner PD.Previous work has shown that replacing N2 in air with He at the same inspired O2 fraction reduces the exercise-induced alveolar-arterial PO2 difference (AaPO2) in horses but has provided no mechanism explaining this effect. We sought to distinguish among possible causes by using the multiple inert gas elimination technique. Six horses were studied on a high-speed treadmill while they breathed either ambient air or normoxic He-O2. O2 uptake reached 138.0 ml.min-1.kg-1 and was not affected by He-O2. Temperature-corrected arterial PO2 was 76.7 Torr (air) and 86.9 Torr (He-O2) (P < 0.01). Corre...
Baker B, Gaffin SL, Wells M, Wessels BC, Brock-Utne JG.Endotoxins (lipopolysaccharides-LPS) and anti-endotoxin IgG antibodies were measured in racehorses before and after races of 1,000, 2,000 and 2,800 m. Results show that the mean plasma concentration of endotoxin increased significantly (p less than 0.02) while the anti-LPS IgG concentration decreased significantly (p less than 0.005) in all horses following the races. Pre-race and post-race anti-LPS IgG levels in racing-fit racehorses were significantly higher than in untrained horses (p less than 0.05). The possibility therefore exists that training-induced stress leads to leakage of LPS into...
Dyson S, Pollard D.The Ridden Horse Pain Ethogram (RHpE) was developed to facilitate the recognition of musculoskeletal pain. The aim of this study was to document changes in RHpE scores before and after diagnostic anaesthesia was performed to alleviate pain ± when the saddle was changed. One hundred and fifty horses underwent ridden exercise as part of an investigation of poor performance. The RHpE was applied before and after the interventions. Fifty-two (34.7%) horses exhibited a bilaterally symmetrical short step length and/or restricted hindlimb impulsion and engagement. Fifty-three (35.3%) horses had epis...
Lejeune JP, Sandersen C, Votion D, Caudron I, Vander Heyden L, Franck T, Ceusters J, Mouithys-Mickalad A, Niesten A, De La Rebière de Pouyade G....Intensive exercise induces a systemic inflammatory response characterised by an increase of blood neutrophil count and myeloperoxidase (MPO) release. Neutrophil elastase (NE) could also contribute to tissues lesions by its proteinase activities. Objective: To compare plasmatic NE concentrations before and after different forms of intensive exercise. Methods: EDTA blood samples were taken from 51 eventing horses (EvH) and 32 endurance horses (EndH) were sampled before the race (T0). Blood sampling was performed 2 h (T1) after completing either phase D of a one or 2 star eventing competition (n ...
Piccione G, Bazzano M, Giannetto C, Marafioti S, Fazio F.The purpose of this study was to investigate the effects of training on prothrombin time, activated partial thromboplastin time, and fibrinogen (Fb) concentrations in horses to assess potential adaptive response to training. Fifteen clinically healthy horses were enrolled in the present study and equally divided into three groups. Group A completed an intense training program, group B participated in a light training program, and group C included sedentary horses. After 5 weeks, group B was subjected to the same training program completed by group A and renamed group B1. Blood samples were col...
Knych HK, Arthur RM, Mitchell MM, Holser I, Poppenga R, Smith LL, Helm MN, Sams RA, Gaskill CL.Cobalt has been used by human athletes due to its purported performance-enhancing effects. It has been suggested that cobalt administration results in enhanced erythropoiesis, secondary to increased circulating erythropoietin (EPO) concentrations leading to improvements in athletic performance. Anecdotal reports of illicit administration of cobalt to horses for its suspected performance enhancing effects have led us to investigate the pharmacokinetics and pharmacodynamic effects of this compound when administered in horses, so as to better regulate its use. In the current study, 18 horses were...
McCutcheon LJ, Geor RJ, Ecker GL, Lindinger MI.This study examined sweating responses in six exercise-trained horses during 21 consecutive days (4 h/day) of exposure to, and daily exercise in, hot humid conditions (32-34 degrees C, 80-85% relative humidity). On days 0, 3, 7, 14, and 21, horses completed a standardized exercise test on a treadmill (6 degrees incline) at a speed eliciting 50% of maximal O(2) uptake until a pulmonary artery temperature of 41.5 degrees C was attained. Sweat was collected at rest, every 5 min during exercise, and during 1 h of standing recovery for measurement of ion composition (Na(+), K(+), and Cl(-)) and swe...
White SL, Williamson LH, Maykuth PL, Cole SP, Andrews FM, Geiser DR.The exercise intensity of horses (n = 175) competing in the cross-country phase of 4 combined training events at 5 levels of competition [novice (N), training (T), preliminary (P), intermediate (I) and advanced (A)] was investigated. Environmental conditions varied from cool and humid (mean +/- s.d. temperature and humidity = 12.1 degrees C +/- 0.6 and 88.4% +/- 8.9 RH) to moderately hot and humid (27.8 degrees C +/- 2.1 and 62.5% +/- 7.8 RH). Heart rates (beats/min) were recorded continuously at 5 s intervals with a heart monitor. Mean +/- s.d. heart rates (beats/min) for each level of compet...
Loup B, André F, Avignon J, Lhuaire M, Delcourt V, Barnabé A, Garcia P, Popot MA, Bailly-Chouriberry L.Short half-life doping substances are, quickly eliminated and therefore difficult to control with traditional analytical chemistry methods. Indirect methods targeting biomarkers constitute an alternative to extend detection time frames in doping control analyses. Gene expression analysis (i.e., transcriptomics) has already shown interesting results in both humans and equines for erythropoietin (EPO), growth hormone (GH), and anabolic androgenic steroid (AAS) misuses. In humans, circulating cell-free microRNAs in plasma were described as new potential biomarkers for control of major doping agen...
Santosuosso E, Leguillette R, Vinardell T, Filho S, Massie S, McCrae P, Johnson S, Rolian C, David F.Background: Swimming is used for rehabilitation and conditioning purposes in equine sports medicine despite the lack of understanding of equine swimming kinematics. The aim of this study was to assess forelimb joints kinematics (elbow, carpus, and fetlock) in swimming horses. The specific objectives were 1- to calculate and compare joint angles in swimming vs. passive mobilizations (PM), 2- to determine joint angular velocities during a swimming stride cycle. Methods: Eleven elite endurance horses swam in a 100-m straight pool. Underwater (swimming) and overground (PM) videos were recorded fro...
Fazio F, Casella S, Giannetto C, Caola G, Piccione G.The aim of the present work was to evaluate the influence of exercise on serum homocysteine and oxidative stress in Thoroughbreds during official races. For our study, ten Thoroughbred mares, 5 years old and clinically healthy, were used. The horses were trained to take part in an official 2100 meter race. Reactive oxygen species (dROMs), antioxidant barrier (Oxy-adsorbent), thiol antioxidant barrier (SHp) and homocysteine (sHcy) were investigated. Blood samples, collected from each horse at rest, immediately after the race, and 30 and 180 min after the end of the race, were collected by jugul...
Hammond A, Sage W, Hezzell M, Smith S, Franklin S, Allen K.Heart rate variability (HRV) analysis measures the inter-beat interval variation of successive cardiac cycles. Measurement of these indices has been used to assess cardiac autonomic modulation and for arrhythmia identification in exercising horses. Objective: To report HRV indices during submaximal exercise, strenuous exercise and recovery, and explore relationships with clinical conditions (arrhythmias, lameness, equine gastric ulcer syndrome [EGUS], lower airway inflammation and upper respiratory tract obstructions [URTOs]) in Thoroughbred racehorses. Methods: Retrospective, observational cr...
Rose RJ, Hodgson DR, Bayly WM, Gollnick PD.To determine whether maximum oxygen uptake (VO2max) in the horse in influenced by type of exercise test, five different protocols were evaluated in eight untrained Thoroughbreds exercised on a treadmill. With all protocols, horses were given a 5 min warm-up on a 10 per cent treadmill slope. Three protocols were at a 10 per cent slope and included: 1) increasing the running speed by 1 to 2 m/sec every 60 secs from 4 m/sec to a maximum of 12 m/sec; 2) running at 12 m/sec until fatigue; and 3) running for 3 to 4 mins at speeds ranging from 6 to 12 m/sec with rest pauses between exercise bouts. Th...
Harris PA, Marlin DJ, Gray J.In order to investigate the effect of age, sex and month on the response of plasma aspartate aminotransferase (AST) and creatine kinase (CK) to exercise, blood samples were collected once a month between March and September from a group of 40 2- and 3-year-old (2yo and 3yo) thoroughbred racehorses (kept under the same managemental regimen) at rest before exercise (PRE) and at 2 (2H) and 24 h (24H) post-exercise. The absolute change in activities between the 2H and PRE samples (2H delta) and the 24H and PRE samples (24H delta) was also calculated. Age had a significant effect on all measured an...
Ichibangase T, Imai K.To extend the applicability of the fluorogenic derivatization-high performance liquid chromatography-tandem mass spectrometry (FD-LC-MS/MS) method, which consists of fluorogenic derivatization (FD), separation by liquid chromatography (LC), and identification by LC-tandem mass spectrometric (MS/MS) proteomic analysis, we applied it to Thoroughbred horse muscle. With the optimization of the protein extraction and separation procedure, reproducible chromatograms were obtained and the changes in protein expressions during exercise were able to be analyzed. To quantify the changed protein expressi...
Schaer BL, Ryan CT, Boston RC, Nunamaker DM.There is a need to determine accelerations acting on the equine hoof under field conditions in order to better assess the risks for orthopaedic health associated with shoeing practices and/or surface conditions. Objective: To measure the acceleration profiles generated in Thoroughbred racehorses exercising at high speeds over dirt racetracks and specifically to evaluate the effect of a toe grab shoe compared to a flat racing plate, using a newly developed wireless data acquisition system (WDAS). Methods: Four Thoroughbred racehorses in training and racing were used. Based on previous trials, e...
Clayton HM.This study was designed to test the hypothesis that there is no significant difference in selected temporal and linear stride variables of the extended canter in horses bred and trained for dressage or racing. Nine advanced-level dressage horses and 7 Thoroughbred racehorses were filmed at a frame rate of 200 Hz at an extended canter on a sand track. Two strides were recorded per trial, and each horse performed 6 or 7 trials. Temporal and linear data were determined from the films, and descriptive statistics (mean, SD) were calculated. Strides were selected for analysis on the basis of having ...
Ellis JM, Hollands T, Allen DE.The horse evolved to survive on rations high in forage. Many performance horses are fed rations containing reduced levels of forage, with a corresponding increase in concentrate supply. Such reductions in forage intake are widely established to be associated with a corresponding number of physiological and psychological adaptations. Therefore, the influence of forage intake on bodyweight (bwt) and performance was investigated. Four Thoroughbred-type geldings in light to moderate work received 4 diets (100% forage [100H]; 80% forage:20% concentrate [80H]; 60% forage:40% concentrate [60H] and 50...
Morrison R, Sutton DG, Ramsoy C, Hunter-Blair N, Carnwath J, Horsfield E, Yam PS.Accelerometers are valid, practical and reliable tools for the measurement of habitual physical activity (PA). Quantification of PA in horses is desirable for use in research and clinical settings. The objective of this study was to evaluate a triaxial accelerometer for objective measurement of PA in the horse by assessment of their practical utility and validity. Horses were recruited to establish both the optimal site of accelerometer attachment and questionnaire designed to explore owner acceptance. Validity and cut-off values were obtained by assessing PA at various gaits. Validation study...
Christley RM, Hodgson DR, Evans DL, Rose RJ.To compare the development of exercise-induced arterial hypoxemia in horses before and after training, and to determine whether increases in maximum oxygen uptake (VO2max) following training results in a greater degree of exercise-induced arterial hypoxemia. Methods: 13 three- to five-year-old. Standardbred geldings without clinical signs of respiratory or cardiovascular disorders. Methods: Horses were rested for 4 months prior to commencing a 16-week training program. Arterial blood was collected from the transverse facial artery during standardized exercise tests performed before and after 8...
Raidal SL, Love DN, Bailey GD, Rose RJ.The effect of strenuous exercise on the functional capacity of pulmonary alveolar macrophages (PAM) and bronchoalveolar lavage-derived lymphocytes was determined in eight horses prior to and after 7 weeks of training. Strenuous exercise had no effect on the total cell count or the percentage of live cells in bronchoalveolar lavage (BAL) samples prior to or following training. However, training was associated with a significant increase in the total cell count of pre-exercise BAL samples and a significant reduction in the percentage of live cells in post-exercise samples. Strenuous exercise was...
Pösö AR.Lactate is known as the end product of anaerobic glycolysis, a pathway that is of key importance during high intensity exercise. Instead of being a waste product lactate is now regarded as a valuable substrate that significantly contributes to the energy production of heart, non-contracting muscles and even brain. The recent cloning of monocarboxylate transporters, a conserved protein family that transports lactate through biological membranes, has given a new insight into the role of lactate in whole body metabolism. This paper reviews current literature on lactate and monocarboxylate transpo...
Gmel AI, Haraldsdóttir EH, Serra Bragança FM, Cruz AM, Neuditschko M, Weishaupt MA.Ground coverage and over-tracking are two gait quality traits describing the forward movement of the front respectively the hind limbs in relation to stride length and over-tracking distance. To investigate the complex interplay of different movement patterns in ground coverage and over-tracking, limb and body kinematics of 24 Franches-Montagnes (FM) stallions were measured with 3D optical motion capture (OMC) on a treadmill during an incremental speed test at the walk (1.4-2.0 m/s). The significance and amount of explained variance of kinematic parameters on stride length and over-tracking di...
van de Lest CH, van den Hoogen BM, van Weeren PR.The object of this study was to determine whether changes in the synovial fluid (SF) induced by in vivo loading can alter the metabolic activity of chondrocytes in vitro, and, if so, whether insulin-like growth factor-I (IGF-I) is responsible for this effect. Therefore, SF was collected from ponies after a period of box rest and after they had been exercised for a week. Normal, unloaded articular cartilage explants were cultured in 20% solutions of these SFs for 4 days and chondrocyte bioactivity was determined by glycosaminoglycan (GAG) turnover (i.e., the incorporation of 35SO4 into GAG and ...
Casella S, Vazzana I, Giudice E, Fazio F, Piccione G.The changes of cortisol, red blood cells (RBC), hemoglobin (Hb), hematocrit (Hct), heart rate (HR), respiratory rate (RR) and rectal temperature (RT) were evaluated after a reining training session in eight Quarter Horses. All parameters were measured before exercise (T0), immediately after exercise (T1), 1 h after exercise (T2), 2 h after exercise (T3) and 24 h after exercise (T4). One-way analysis of variance (ANOVA) for repeated measures, followed Bonferroni's post hoc test, showed a significant effect of the reining training session (P < 0.0001) on cortisol, RBC, Hb, Hct, HR, RR and RT. Si...
Mihelić K, Vrbanac Z, Bojanić K, Kostanjšak T, Ljubić BB, Gotić J, Vnuk D, Bottegaro NB.This study aimed to evaluate if exercise-induced acute phase response (APR) occurs in endurance horses in response to the race. The study included 23 horses competing in an endurance competition with a successfully passed clinical examination before the race. Blood samples were collected before the start and within 30 min after the end of the race. Haematological and biochemical tests were performed and correlated to acute phase biomarkers changes. Values of calprotectin and haptoglobin (Hp) decreased after the races compared to values before, while concentrations of ceruloplasmin and albumin ...
Murray R, Mackechnie-Guire R, Fisher M, Fairfax V.Back pain is frequently recognized in racehorses, but saddle fit and design are rarely assessed. In sport horses, relationships between horse-saddle interaction, back pain, and altered kinematics are established, but few studies investigating horse-saddle interaction in racehorses exist. We hypothesized that reducing pressures under saddles at thoracic (T) vertebrae 10-13 in galloping racehorses is associated with improved limb and lumbosacral kinematics. The objectives of the study were to (1) determine pressure magnitude/distribution under 3 frequently used race-exercise saddles and a saddle...
