Exercise in horses encompasses the physical activities that horses engage in, either through natural behaviors or structured training programs. These activities impact a horse's musculoskeletal, cardiovascular, and respiratory systems, influencing overall health and performance. Exercise can vary in intensity, duration, and frequency, and its effects are studied to understand conditioning, endurance, and recovery processes in equines. Research in this field often focuses on the physiological adaptations to different types of exercise, the prevention of exercise-related injuries, and the optimization of training regimens for various equestrian disciplines. This page compiles peer-reviewed research studies and scholarly articles that explore the physiological, biomechanical, and health-related aspects of exercise in horses.
Sweeney CR, Soma LR.Of 61 horses with a history of exercise-induced pulmonary hemorrhage and treated with furosemide 4 hours prior to racing, 34 (55.7%) continued to bleed. Of 24 horses with exercise-induced pulmonary hemorrhage that were not treated with furosemide prior to racing, 17 (70.8%) still bled. There was no statistically significant difference between the treated and the nontreated groups. Of 45 horses given hesperidin-citrus bioflavinoids, 38 (84.4%) bled when exercised 90 days later. There was no statistically significant difference between the results for hesperidin-citrus bioflavinoid-treated horse...
Sweeney CR, Soma LR, Bucan CA, Ray SG.Thoroughbreds with a confirmed history of exercise-induced pulmonary hemorrhage (EIPH) were treated pre-exercise with atropine sulfate, cromolyn, ipratropium or furosemide. Atropine prevented EIPH in 3 of 3 trials in 1 horse, while having no significant effect on bleeding status in the other 2 horses. Pre-exercise treatment with cromolyn had no significant effects in the 3 horses. Pre-exercise treatment of ipratropium was apparently responsible for preventing EIPH in 17 out of 18 trials in 2 horses. The pharmacologic properties of ipratropium in the horse have not been studied, but based on hu...
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 ...
Leach DH, Ormrod K, Clayton HM.An investigation was made of the stride characteristics of horses jumping 2 obstacles during a Grand Prix competition. One obstacle was a picket fence and rail 1.3 m high (fence 2), and the other was a coop and rail 1.52 m high (fence 11). Thirteen distance and 22 timing measurements of 17 horses were extracted from high-speed films, using computer-aided analysis. These data were used to compare takeoff and landing of the lead and nonlead legs, the thoracic limbs and pelvic limbs, and fence 2 and fence 11. Paired t-tests were used to compare means and a stepwise regression analysis was done fo...
Szwarocka-Priebe T, Gill J.Twenty Thoroughbred 3 year old horses (10 stallions and 10 mares), trained and raced at the Warsaw Race-Course were studied from March through November. Blood was taken approximately every 8 weeks to determine the activities of aspartate and alanine transaminases, acid and alkaline phosphatases and aldolase. It was observed that the activities of aspartate aminotransferase and alkaline phosphatase reached their maxima in July and alanine transaminase in May. The activities of acid phosphatase and aldolase showed their minima in July. Comparing these data with the literature it was noted that t...
Bayly WM, Grant BD, Modransky PD.Arterial blood samples were collected during maximal exercise over 1.6 km in a thoroughbred horse with left laryngeal hemiplegia. Acid-base and blood gas measurements were performed on each sample and compared to the results from samples which were similarly collected 48 hours after laryngoplasty surgery was performed. Before surgery, the PaO2 was 53.2 mm Hg and the PaCO2 was 58.1 mm Hg after 1.6 km. After surgery, the corresponding results were 83.6 mm Hg (PaO2) and 39.0 mm Hg (PaCO2). There was no significant difference in the times taken for each gallop. The exercise intolerance associated ...
Hodgson DR, Rose RJ, Allen JR, Dimauro J.Muscle biopsy samples were collected from the left middle gluteal muscle of horses participating in competitive barrier trials. Twelve horses were biopsied the day before and within 30 minutes of completion of an 800 m barrier trial. A further six horses were sampled the day before, and within 30 minutes of, completion of a 1200 m barrier trial. Serial muscle sections were examined histochemically for myosin adenosine triphosphatase activity after acid preincubation, to demonstrate type I, IIA and IIB fibres. The glycogen content in the individual fibres was assessed using the periodic acid Sc...
Owen RA, Marsh JA, Hallett FR, Lumsden JH, Johnson J.Methylprednisolone acetate was injected repeatedly into both intercarpal joints of a horse that had a 3rd carpal bone fracture in 1 limb. Synovial fluid from intercarpal and radiocarpal joints of both limbs were obtained serially for study. Arthropathy developed in the fractured joint following prolonged corticosteroid therapy and exercise. In the corticosteroid-injected normal joint, the hyaluronic acid concentration initially decreased, then increased. A depletion in cartilage matrix was seen at necropsy, 175 days after onset of treatment. Determination of total protein content in synovial f...
Littlejohn A, Howell W, Killeen V.In ten Thoroughbred racehorses which suffered epistaxis during a race, the mean pulmonary arterial diastolic pressure (PADP) was significantly higher, and the mean pulmonary arterial oxygen tension (PaO2) was significantly lower, than the corresponding mean values of a sample of fourteen clinically normal Thoroughbreds in training. The authors conclude that in horses with epistaxis during a race, pulmonary dysfunction may persist for up to two months after the episode, and that the results indicate a need for pulmonary function studies before and after racing, in order to resolve problems conc...
Straub R, Isler R, Gysin J.The incremental three work loads test as a basis test, and the one work load test, in which one measures the heart rate and the serum lactic acid concentration, lead to the performance index values V4 and V150. These values are of great practical importance in judging the performance capacity, the ability to be trained, the trainings effectivity, and determining the optimal work load for interval training.
Matlina E.The investigation of catecholamine (CA) metabolism in animals subjected to various types of stress (different pain syndromes; cranial trauma; immobilization; cooling) and physical exercise shows considerable similarity among species in the sequence of changes, leading from the activation to the depletion of the sympathoadrenal system. The changes caused by physical exercise tend to be more pronounced in individuals with a genetic predisposition to greater stress responses. Stress adaption, induced by special training or by long-duration exposure to hypoxia, can substantially prevent the change...
Parks CM, Manohar M.Blood-gas tensions and acid-base status were examined in 8 healthy grade ponies at rest (heart rate = 55 +/- 3 beats/min) and during moderate (fast trot; heart rate = 155 +/- 3 beats/min) and severe (gallop; heart rate = 218 +/- 7 beats/min) exercise performed on a treadmill. Arterial oxygen tension and hemoglobin-oxygen saturation of exercising ponies did not change from the resting values. Arterial oxygen content increased markedly during exercise, as a consequence of increased hemoglobin concentration. The total oxygen content, as well as the saturation of hemoglobin with oxygen in the mixe...
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...
van den Hoven R.Venous lactate concentrations were determined in standard-bred trotters following exercise of varying intensity to obtain a useful parameter in determining the working capacity of horses. After standard exercise, well-trained horses produced less lactate than did inadequately trained horses. During the post-exercise resting period, lactate disappeared faster from the blood in well-trained horses and young lightly trained horses than it did in poorly trained horses. Steady-state training resulted in lower lactate levels than those recorded after racing, whereas interval training resulted in the...
Rollinson EA, White G.Compound BW759 (9-[2-hydroxy-1-(hydroxymethyl)ethoxymethyl]guanine) was shown to be about 230 times more active than acyclovir (9-[2-hydroxyethoxymethyl]guanine) (ACV) against Equid herpesvirus type 1 infection in Syrian hamsters and was more effective against Aujeszky's disease in mice. The therapeutic superiority of BW759 over ACV was greater than expected from quantitative inhibitory results in tissue culture with these viruses. When administered to hamsters at dose rates sufficient to prevent any Equid herpesvirus type 1-induced mortality (100 mg of ACV per kg per day; 3 mg of BW759 per kg...
Kerr MG, Snow DH.Temporal changes in sweat composition were studied in 4 horses during epinephrine (adrenaline) infusion (0.13 to 0.31 micrograms/kg/min for 3 hours), heat exposure (41 C, [33 C wet bulb] for 5 to 6 hours), and exercise (16 to 18 km/hr for 58 to 80 km). Four ponies also were studied during heat exposure. Sweat produced by each of the stimuli was hypertonic for Na+, K+, and Cl-. These electrolyte concentrations remained constant during the central period of the experiments, with changes occurring near the beginning and toward the end. The Na+ was significantly higher and K+ significantly lower i...
Thomas DP, Fregin GF, Gerber NH, Ailes NB.The effects of 5- and 10-wk treadmill exercise training on cardiorespiratory function were evaluated in the horse. Cardiac output (Q), heart rate (HR), and stroke volume (SV), as well as left ventricular (LVP), aortic (AoP), and mean right atrial (RAP) pressures and the peak first time derivative of LVP (LV dP/dtmax), were measured at rest and at five different levels of exercise up to 90% of initial predicted maximal HR (HRmax). Oxygen uptake (VO2) and respiratory exchange ratio (R) were also obtained under the same conditions. At rest, although HR was no different after training, LV dP/dtmax...
Tulamo RM, Bramlage LR, Gabel AA.The case histories and follow-up data for 11 horses with slab fractures of the central or 3rd tarsal bones were examined for information pertaining to the diagnosis, which was difficult to identify, treatment, which was proven ineffective, and the prognosis, which was shown to be poor for return to racing. The purpose of the study was to define the results that could be obtained by nonoperative methods, in an attempt to determine whether surgical treatment was advisable. Nine of the horses were Standardbreds and 2 were Thoroughbreds; all horses were 2 to 4 years old and were being exercised at...
Pan LG, Forster HV, Bisgard GE, Kaminski RP, Dorsey SM, Busch MA.We studied blood gases in ponies to assess the relationship of alveolar ventilation (VA) to pulmonary CO2 delivery during moderate treadmill exercise. In normal ponies for 1.8, 3, or 6 mph, respectively, partial pressure of CO2 in arterial blood (PaCO2) decreased maximally by 3.1, 4.4, and 5.7 Torr at 30-90 s of exercise and remained below rest by 1.4, 2.3, and 4.5 Torr during steady-state (4-8 min) exercise (P less than 0.01). Partial pressure of O2 in arterial blood (PaO2) and arterial pH, (pHa) also reflected hyperventilation. Mixed venus CO2 partial pressure (PVCO2) decreased 2.3 and 2.9 T...
Fredricson I, Drevemo S, Dalin G, Hjertén G, Björne K, Rynde R, Franzen G.A treadmill for equine locomotion analysis is described and its potential considered for locomotive research and clinical investigation. The treadmill comprised an endless belt driven by a hydraulic motor at various speeds up to 14 m/sec and the direction of belt movement was reversible. The carrying side of the belt ran over a steel-concrete table which acted as a flat support. The belt itself consisted of a steel base on to which was glued a rubber belt and the surface was covered with a layer of coir matting which permitted some forward sliding of the landing hooves simulating the condition...
Snow DH, Ricketts SW, Mason DK.The haematological response to racing and to fast and slow training exercise was investigated in studies involving two populations of horses which differed widely in geographical location, climatic factors and management (Newmarket and Hong Kong). The well documented elevations in erythrocyte parameters were demonstrated and changing responses in leucocyte parameters, resulting in variations in the neutrophil to lymphocyte (N/L) ratio were described. It was shown that the immediate response to the anticipation or stress of exercise was a decrease in N/L ratio in association with an increase in...
Rose RJ, Hodgson DR, Sampson D, Chan W.Plasma biochemical values were measured in 14 horses, before a 160 km endurance ride, immediately after 85 km, immediately after 160 km, after 30 min recovery period and the day after the ride. For statistical analysis, a group of 7 horses that completed the ride at a mean speed of 234 metres per min (m/min) (Fast Group) was compared with 7 horses that completed the ride at a mean speed of 144 m/min (Slow Group). Estimations were made of sodium, potassium, chloride, bicarbonate, glucose, creatinine, urea, bilirubin, iron, total protein, albumin, calcium, phosphate, cholesterol, alkaline phosph...
Turner TA, Fessler JF, Lamp M, Pearce JA, Geddes LA.The distal forelimbs of 10 clinically normal horses with hair clipped on 1 limb were thermographically scanned before and after exercise. The thermal patterns, temperature distribution, and temperature changes after exercise were determined and compared with those of 8 horses with podotrochlosis. Clipping the hair did not cause changes in the thermal patterns, but the clipped limbs were warmer than the unclipped limbs. The temperature of the limbs of horses with podotrochlosis did not increase as much after exercise as did the limbs of normal horses. The failure of skin temperature increase co...
Bayly WM, Gabel AA, Barr SA.Seven healthy, unexercised, previously trained, adult Standardbred horses were allotted to 2 groups and trained 78 days on a treadmill set at a 7 degree 30' angle. The groups were trained on different schedules, and the effects of training on heart rate, cardiac output, stroke volume, arteriovenous oxygen difference, systemic blood pressure, and venous lactic acid were determined. Measurements were made at rest, during exercise on the treadmill at rates of 55 m/min, 75 m/min, 100 m/min, and 154 m/min, and at 5 minutes after exercise (standardized exercise test). Heart rate and cardiac output d...
Georgiev P, Petkov PI, Georgiev Kh, Bŭrzev G.Parallel physiologic, biochemical, and hormonal investigations of racehorses were carried out within the time period of a training cycle. The changes found in the physiologic and biochemical indices were said to be in a general relationship with the amount of physical training of the animals, at the same time reflecting some seasonal variations. The changes in the level of T-4 and cortisol were found to be in direct relationship with the continuation of training.
Gaughan EM.Skeletal origins of exercise intolerance and performance failure can reside in multiple tissues. Diagnosis of injury that results in an ability to continue to exercise, yet inefficiently do so, requires familiarity with evaluation of subtle lameness and often with the specific demands of the different equine sports. Imaging is usually vital to diagnosis development and understanding of lesion influences on locomotion. Therapy is lesion dependent. Return to competitive exercise and performance is dictated by an understanding of skeletal tissue response to injury, rational progressive treatment,...
Rothhaupt D, Ziegler H, Laser T.The orthopedic hippotherapy represents a new form of therapeutic exercise in the conservative treatment of segmental instabilities in the lumbar spine region. This kind of therapy works on the principle of conveying to the patient the three-dimensional swinging motion of the horse's back. The patient reacts to these movement impulses by moving up and down (vertical movement of the spine), back and forth (sagittal movement) and to the right and the left (horizontal movement). The small movements of the spine thus produced bring about a mobilization of the segments involved in movement and there...
Schott HC, Bohart GV, Eberhart SW.Efflux of potassium (K+) and lactate (lac-) from active skeletal muscle during high intensity exercise leads to increased plasma [K+] and [lac-] in venous and arterial blood. The exercise-induced increases in these ions in human athletes is ameliorated, in part, by uptake by noncontracting tissue, reflected by an increase in the arteriovenous difference across these tissues from rest to exercise. To test the hypothesis that these ions are taken up by noncontracting tissue in strenuously exercising horses, plasma [K+] and [lac-] were measured in blood samples collected simultaneously from the c...
Beech J, Lindborg S, Braund KG.Potassium concentrations were measured in semimembranosus muscle, plasma and erythrocytes, and the urinary fractional excretion determined in normal horses and those that had chronic intermittent exercise-associated rhabdomyolysis. Muscle from the rhabdomyolysis horses was also evaluated microscopically. The horses with rhabdomyolysis had a lower muscle potassium concentration on a dry weight basis. Although the wet weight potassium content was also lower, the difference was not significant. Urinary fractional excretion of potassium (and also sodium and chloride) did not differ significantly b...
Branch MV, Murray RC, Dyson SJ, Goodship AE.Understanding of the development of pathology and source of pain in distal tarsal osteoarthritis is poorly understood. Magnetic resonance imaging is often used in the analysis of human osteoarthritis (OA) because it is sensitive to early changes. Objective: In association with distal tarsal joint (DTJ) pain, there will be an alteration in the characteristic subchondral bone (SCB) thickness pattern of horses with no history of pain when subjected to low-level exercise. Methods: Sixteen cadaver tarsal joints were collected from 9 mature horses with a history of tarsal pain and radiographic evide...
von Rennenkampff F, Kraft H.During 20 weeks blood constituents in peripheral blood (Erythrocyte count, Packed cell volume, Hemoglobin, Sedimentation rate, activities of Aspartate aminotransferase, Alanine aminotransferase, Creatine phosphokinase, Lactate dehydrogenase, Lactate dehydrogenase-1-isoenzyme, Glucose, Lactate, Total bilirubin), pulse and respiration rate were determined at rest and after exercise. Significant increase of blood values after exercise could be noted in relation to the intensity of exercise and the performance of the animals. The well trained horses had an increase of their performance according t...
Pasławska U, Zyśko D, Noszczyk-Nowak A, Pasławski R.The duration of electrocardiographic (ECG) parameters: PQ, QT and R-R intervals change during long-term and short-term observation as the consequence of the fluctuations in autonomic nervous system activity among others dependent on the exercise and resting. There is no data of horse breed influence on these parameters. The aim of the study was to assess the duration and the variability of the PQ, QT and R-R intervals in the resting conditions and after exercise testing in Anglo-Arabian horses. Methods: 27 healthy Anglo-Arabian horses aged 3.4 +/- 1.0 years (15 male, 12 female) had ECG examina...
Schwarz J, Vidondo B, Maninchedda UE, Sprick M, Schöpfer MC, Cruz AM. To assess the inter-evaluator and intra-evaluator reliability of a software program used to extract kinematic variables by a commercially available extremity-mounted inertial measurement unit system in sound horses at the trot under soft and hard ground conditions and treadmill exercise. Thirty adult, sound and healthy French Montagne stallions. Data collection was performed with six IMUs strapped to the distal, metacarpal, metatarsal and tibial regions of every horse. Per surface (treadmill, soft and hard ground) 10 stallions were trotted three times. Prior to the analysis done by six eval...
Bolwell CF, Rogers CW, French NP, Firth EC.There is increasing evidence suggesting that early exercise in Thoroughbred racehorses may be beneficial to the development of the musculoskeletal system. At present, information on the exercise programmes and health problems of individual yearlings during a sales preparation is scant. Objective: To describe the exercise and health problems of Thoroughbred yearlings during preparation for sales, and to identify variations in exercise between and within farms. Methods: A prospective cohort study was used to collect exercise and health information from 18 farms across New Zealand. Daily exercise...
Hinchcliff KW, McKeever KH.The effect of blood volume repletion after frusemide administration on the right atrial and pulmonary artery pressure responses of horses to exercise has not been reported. We examined right atrial and pulmonary artery pressure and plasma atrial natriuretic peptide concentration (ANP) responses to an incremental exercise test in 6 Standardbred mares. Horses were treated, in a 3 way cross over design, with isotonic saline, frusemide (1 mg/kg bwt, i.v.), and frusemide followed 3 h later by lactated Ringer's solution (12 ml/kg bwt, i.v.). Three and a half hours after saline or frusemide administr...
Baragli P, Ducci M, Gatta D, Gazzano A, Sighieri C.Catecholamines (CAT) play an important role in modulating the response to exercise. But the kinetics of CAT changes during exercise are difficult to study due to their short biological half-life. Objective: Learning about variations in plasma CAT levels during training could furnish new information regarding sweating, redistribution of blood flow and energy metabolism. Methods: Four untrained Standardbreds, adapted to treadmill work, were used to determine the influence of training on plasma adrenaline (A) and noradrenaline (NA) kinetics. Horses underwent a standardised exercise test (SET) on ...
Knych HK, Stanley SD, McKemie DS, Arthur RM, Bondesson U, Hedeland M, Thevis M, Kass PH.Although developed as a therapeutic medication, meldonium has found widespread use in human sports and was recently added to the World Anti-Doping Agency's list of prohibited substances. Its reported abuse potential in human sports has led to concern by regulatory authorities about the possible misuse of meldonium in equine athletics. The potential abuse in equine athletes along with the limited data available regarding the pharmacokinetics and pharmacodynamics of meldonium in horses necessitates further study. Eight exercised adult thoroughbred horses received a single oral dose of 3.5, 7.1, ...
Smale K, Butler PJ.A new oxygen equilibrium curve is defined for the Thoroughbred horse under standard conditions of 37 degrees C, pH = 7.4 and PCO2 = 5.33 kPa. The "standard" P50 for the Thoroughbred is, at 2.83 +/- 0.04 (SE of mean) kPa, significantly lower than that found for the Hanoverian horse (3.17 +/- 0.03 kPa) by Clerbaux et al. (Can. J. Vet. Res. 50: 188-192, 1986), and lower than other values for horses in the literature. Using data from Butler et al. (J. Exp. Biol. 179: 159-180, 1993), curves were also constructed, in vitro, under simulated conditions of intense exercise to examine the individual eff...
Weiss DJ, Evanson OA, McClenahan D, Fagliari J, Walcheck B.To determine whether platelets become activated and form platelet-platelet or platelet-neutrophil aggregates, or both, when subjected to shear. Methods: Blood obtained from 3 Thoroughbreds. Methods: Blood, with PCV adjusted to 32 (low hematocrit) or 60 (high hematocrit)%, was subjected to shear rates of 11.25, 22.5, 45, 90, 225, and 750/s for 3 minutes by use of a cone-plate viscometer. Flow cytometric techniques were used to identify activated platelets, platelet-platelet aggregates, and platelet-neutrophil aggregates. Results: Shear resulted in decreased platelet count, increased mean platel...
Powell D, Lawrence LM, Brewster-Barnes T, Fitzgerald B, Warren LK, Rokuroda S, Parker A, Crum A.Eight Thoroughbred horses were used to determine the effects of long-term calorie restriction and diet composition on serum T4 and T3 concentrations and metabolic responses with exercise. Horses were randomly assigned to 2 treatment groups (n = 4): Group 1, horses were fed a calorie-restricted diet designed to have 70% of the calories from the roughage source (RHR); Group 2, horses were fed a calorie-restricted diet designed to have 70% of the calories from the concentrate source (RHC). Horses then completed 2 step-wise exercise tests; one following a 12 h fast and one 2 h after a meal of 2 kg...
Sexton WL, Erickson HH.Six ponies performed a standardised exercise test on a motorised treadmill at each of three randomly assigned treadmill elevations (1, 4, or 7 degrees). The exercise test consisted of four, 4 min increments of increasing treadmill speed from 1.0 to 3.4 m/sec. Heart rate, blood lactate concentration, and packed cell volume (PCV) were determined, during the last min of each exercise level, and at 4 and 12 mins post exercise. Regardless of treadmill elevation, no differences were observed in pre-exercise heart rate (49 +/- 2) beats/min), lactate (1.2 +/- 0.1 mM), and PCV (0.32 +/- 0.01 litres. Du...
Baragli P, Tedeschi D, Gatta D, Martelli F, Sighieri C.The aim of the present study was to test a constant blood withdrawal method (CBWM) to collect blood samples from horses during treadmill exercise. CBWM was performed in 4 Standardbreds and 5 Haflinger horses. A peristaltic pump was used to control blood aspiration from an i.v. catheter via an extension line. Blood was collected using an automatic fractions collector, with a constant delay time between the drawing of blood and sample collection. Blood withdrawal using CBWM was made during a treadmill standardised exercise test (SET). A blood flow of 12 m/min was used and samples collected every...
Potts S, Thatcher R, Jones AW, Warren LK, Tenbroeck SH, Nottage F, McEwan NR.Sweating is important in regulating body temperature but can be a source of loss of both fluids and electrolytes. Although the process has been studied in horses, the variation in sweat osmolarity across the body has not. Objective: This work describes an investigation to determine if there is regional variation in the osmolarity of sweat across different anatomical regions of the horse. Methods: Ten horses were used in the study and were animals either stabled for riding lessons or had livery on-site. Methods: Sweat samples were collected from five regions on each horse following exercise and...
Gottlieb-Vedi M, Lindholm A.The responses in heart rate, plasma lactate and rectal temperature of standardbred trotters to draught loaded interval exercise on a treadmill and a race track were studied. The horses were exercised with incrementally increasing trotting speeds for two-minute intervals with draught loads of 10, 20 and 30 kilopond (kp) in three different tests. Each trotting interval was followed by two-minute periods at a walk without a draught load. Measurements of heart rate and plasma lactate were made at the end of each interval and the rectal temperature was taken at the end of the exercise. The heart ra...
Rose RJ, Ilkiw JE, Hodgson D.Thirty-one horses competing in a 100 kilometre endurance ride had electrocardiograms recorded before and after the ride from which the heart score of each horse was calculated. Blood was also taken to determine the packed cell volume (PCV) and total plasma protein (TPP) before the ride, after 60 kilometres (mid-ride) and at completion of the ride. Statistical analysis of the heart scores showed that a faster group of horses had significantly higher heart scores than either a slower group or those eliminated due to inadequate recovery of heart rate. No horses developed electrocardiogram abnorma...
Minami Y, Yamano S, Kawai M, Hiraga A, Miyata H.To find a new parameter indicating muscle fitness in Thoroughbred horses, we examined time-dependent recovery of glycogen content and sarcoplasmic reticulum (SR) Ca(2+)-ATPase activity of skeletal muscle after intensive treadmill running. Two repeated 50-sec running sessions (13 m/sec) were performed on a flat treadmill (approximately 90%VO2max). Muscle samples of the middle gluteal muscle were taken before exercise (pre) and 1 min, 20 min, 60 min, and 24 hr after exercise. Muscle fiber type composition was determined in the pre muscle samples by immunohistochemical staining with monoclonal an...
Rainger JE, Evans DL, Hodgson DR, Rose RJ.The influence of training on blood lactate concentrations during treadmill exercise and a 40-minute inactive recovery period was examined in seven trained and seven detrained thoroughbred horses. Lactate concentrations were measured in venous blood collected at the end of each exercise state, and at intervals for 40 minutes afterwards. Measurements were made of maximum oxygen uptake (VO2max, ml kg-1 min-1), VLA4 (velocity at which blood lactate concentration was 4 mmol litre-1); LA8 (lactate concentration [mmol litre-1] during exercise at 8 m sec-1), peak lactate (highest lactate concentration...
McCrae P, Guigand C, Jones KB, Thueson ES, Troudt TA, Warlick LM, Sides RH, Jones JH, Bayly WM, Léguillette R.High pulmonary blood pressure contributes to exercise-induced pulmonary hemorrhage. The objective of this study was to use bioimpedance spectroscopy to assess body fluid compartment volumes under 3 conditions in 6 racehorses: i) Pre- and post-supramaximal treadmill exercise (control); ii) Exercise 4 hours after furosemide (0.5 mg/kg body weight, IV); iii) Exercise, removal of ~14 L of blood and subsequent reinfusion of the blood. Statistical analysis used linear mixed effects models. Body compartment volumes did not change during the control runs. Total body water (TBW) ( = 0.007, = 0.007), e...
Suwannachot P, Verkleij CB, Kocsis S, van Weeren PR, Evertst ME.The purpose of the present study was to determine whether training and detraining affect the Na+,K+-ATPase concentration in horse skeletal muscles, and whether these effects are specific for the muscles involved in the training programme. Twenty-four Dutch Warmblood foals age 7 days were assigned randomly to 3 groups: Box (box-rest without training), Training (box-rest with training: short-sprint) and Pasture (pasture without training). Exercise regimens were carried out for 5 months and were followed by 6 months of detraining. Five of the foals in each group were subjected to euthanasia at ag...
Krzywanek H, Mohr E, Mill J, Scharpenack M.Until the age of about 2 years, trotters normally grow up on pasture without any kind of training. In the stud farm Lindenhof (Templin, Germany), however, these first 2 years are used for a special fitness training for the young animals: 2-3 times a week, a group of the yearlings is forced to run a distance of about 1700 m on a track at an average speed of up to 10 m/s. Until now, little was known about changes of blood parameters which may occur during such special exercise. This study therefore investigated the activity of selected serum enzymes (aspartate-amino-transferase (AST), alanine-am...
Marr CM, Bright JM, Marlin DJ, Harris PA, Roberts CA.We hypothesised that exercise in a hot and humid environment would affect echocardiographic indices of cardiac dimensions and function more than exercise in a cool environment. M-mode echocardiograms were obtained in 5 clinically normal horses before, and at 0, 10, 30 and 60 min after a treadmill exercise test. The test was performed in a controlled environment at 20 degrees C/40% relative humidity (RH) and again at 30 degrees C/80% RH. All the horses completed the exercise test in cool conditions, but only one horse completed the exercise test in the hot/humid environment. The relaxation time...
Gerken DF, Sams RA.Although all the factors discussed in this article may have an effect on drug withholding time estimates, the factors that have the potential for the greatest effect or that have been found to cause positive tests in the past are 1. Dosage: Increasing the drug dosage will require a longer withholding time. 2. Dosing interval: Narrowing the dosing interval will require a longer withholding time. 3. Administration route: In general, oral administration results in lower peak plasma concentrations but may result in longer excretion in the urine and therefore longer withholding time. 4. Drug intera...
Holcombe SJ, Derksen FJ, Stick JA, Robinson NE.To determine the effect of bilateral tenectomy of the tensor veli palatini muscle on soft palate and nasopharyngeal function in exercising horses. Methods: 5 Standardbreds. Methods: Treadmill videoendoscopy was performed on 5 Standardbreds exercising at 50, 75, and 100% of the speed that produced maximum heart rate; tracheal and pharyngeal pressures were measured before and after surgery. Tenectomy of the tensor veli palatini muscle was performed bilaterally on each horse while under general anesthesia, using a transoral approach. Results: Peak inspiratory tracheal pressures were significantly...
Simons V, Weller R, Stubbs NC, Rombach N, Pfau T.Training and rehabilitation techniques which improve core muscle strength are beneficial for improvement of dynamic stability of the equine vertebral column. The Equiband™ system, consisting of resistance bands attached to a customised saddle pad, is suggested to provide constant proprioceptive feedback during motion to encourage recruitment of abdominal and hindquarter musculature. Objective: To quantify the effect of the Equiband™ system on back kinematics and movement symmetry. Methods: Longitudinal intervention study. Methods: Quantitative analysis of back movement and gait symmetry be...
Chapman DI, Close PM, Moss MS, Snow DH.A radioimmunological method was used as a screening procedure to determine the period of detection or "clearance time", for the horse, of therapeutic doses of the synthetic anabolic steroid nandrolone phenylpropionate. Seven horses, either at rest or being exercised, were given a course of weekly intramuscular injections of the steroid. On the separate occasion, some of the horses were given a single intramuscular injection of the same compound. The weekly injections maintained a high plasma concentration of nandrolone and/or metabolites. The mean (+/- sd) period of detection in plasma of thes...
