Treadmill exercise for horses involves the use of a controlled mechanical platform to simulate various gaits and intensities of physical activity. This form of exercise allows for consistent and measurable training conditions, which can be used for rehabilitation, fitness assessment, and performance enhancement. Treadmill exercise facilitates the study of equine locomotion, respiratory function, and cardiovascular response under standardized conditions. It is also utilized in research to evaluate the effects of different training regimens and to investigate metabolic and physiological responses to exercise. This page compiles peer-reviewed research studies and scholarly articles that explore the methodology, applications, and implications of treadmill exercise in equine practice.
Padilla DJ, McDonough P, Kindig CA, Erickson HH, Poole DC.Despite enormous rates of minute ventilation (Ve) in the galloping Thoroughbred (TB) horse, the energetic demands of exercise conspire to raise arterial Pco(2) (i.e., induce hypercapnia). If locomotory-respiratory coupling (LRC) is an obligatory facilitator of high Ve in the horse such as those found during galloping (Bramble and Carrier. Science 219: 251-256, 1983), Ve should drop precipitously when LRC ceases at the galloptrot transition, thus exacerbating the hypercapnia. TB horses (n = 5) were run to volitional fatigue on a motor-driven treadmill (1 m/s increments; 14-15 m/s) to study the ...
McKenzie EC, Valberg SJ, Godden SM, Finno CJ, Murphy MJ.To determine the effect of oral administration of dantrolene sodium on serum creatine kinase (CK) activity after exercise in horses with recurrent exertional rhabdomyolysis (RER). Methods: 2 healthy horses and 5 Thoroughbreds with RER. Methods: 3 horses received 2 doses of dantrolene (4, 6, or 8 mg/kg, p.o., with and without withdrawal of food) 2 days apart; 90 minutes after dosing, plasma dantrolene concentration was measured spectrofluorometrically. On the basis of these results, 5 Thoroughbreds with RER from which food was withheld received dantrolene (4 mg/kg) or an inert treatment (water ...
Jackson BF, Goodship AE, Eastell R, Price JS.To evaluate changes in serum concentrations of biochemical markers of bone metabolism and insulin-like growth factor I (IGF-I) associated with treadmill exercise in young horses. Methods: 12 two-year-old Thoroughbred mares. Methods: During a 20-week study period, 6 horses were exercised on a treadmill 3 times a week (exercise group) and 6 horses received walking exercise 6 days a week (controls). Serum concentrations or activity of biochemical markers and IGF-I were assessed biweekly. Bone mineral density and content of the first phalanx were measured by dual-energy X-ray absorbiometry (DEXA) ...
Eto D, Yamano S, Kasashima Y, Sugiura T, Nasu T, Tokuriki M, Miyata H.Most racehorses are trained regularly from about age 18 months; therefore, little information is available on the effect of training in Thoroughbred foals. Objective: Well-controlled exercise could improve muscle potential ability for endurance running. Methods: Thoroughbred foals at age 2 months were separated into control and training (treadmill exercise) groups and samples obtained from the middle gluteal muscle at 2 and 12 months post partum. Muscle fibre compositions were determined by histochemical and electrophoretical techniques and succinic dehydrogenase (SDH) activity was analysed in...
Hackett RP, Ducharme NG, Gleed RD, Mitchell L, Soderholm LV, Erickson BK, Erb HN.To test the hypothesis that the pulmonary vascular pressures of Thoroughbred and Standardbred horses behave similarly during exertion. Measurements were made on 5 Thoroughbred and 5 Standardbred horses on a treadmill at rest and during 3-minute exercise intervals at speeds predicted to produce 75%, 90%, and 100% maximal heart rate. Left forelimb acceleration, heart rate, esophageal pressure, and pulmonary artery pressure were measured continuously. Pulmonary capillary and wedge pressures were measured during intermittent occlusion of the pulmonary artery. Breathing rate and gait frequency were...
Zucca E, Ferrucci F, Di Fabio V, Croci C, Ferro E.The research examines the use of Holter monitoring combined with treadmill exercise to better understand and diagnose cardiac arrhythmias in racehorses. This technology provides a comprehensive view of the horse’s […]
McKenzie EC, Valberg SJ, Godden SM, Pagan JD, MacLeay JM, Geor RJ, Carlson GP.To determine the effect of dietary starch, bicarbonate, and fat content on metabolic responses and serum creatine kinase (CK) activity in exercising Thoroughbreds with recurrent exertional rhabdomyolysis (RER), 5 RER horses were fed 3 isocaloric diets (28.8 Mcal/d [120.5 MJ/d]) for 3 weeks in a crossover design and exercised for 30 minutes on a treadmill 5 days/wk. On the last day of each diet, an incremental standardized exercise test (SET) was performed. The starch diet contained 40% digestible energy (DE) as starch and 5% as fat: the bicarbonate-starch diet was identical but was supplemente...
Back W, Remmen JL, Knaap J, de Koning JJ.Lateral heel wedges are used to treat horses and ponies with patella fixation or bone spavin. However, these therapies are purely empirically based and lack scientific evidence. Objective: Lateral heel wedges would change joint motion in the sagittal, but mainly in the transversal planes, in healthy horses. This effect would be increased by restricted feeding and decreased by extra training. Methods: A group of 24 Shetland ponies age 3 years was used, as foals had been assigned to restricted and ad libitum (ad lib) feeding, and low and high level training groups of 6 animals each. An experienc...
Kindig CA, Ramsel C, McDonough P, Poole DC, Erickson HH.Capillary stress failure-induced (exercise-induced) pulmonary haemorrhage (EIPH) during intense running in horses is thought to involve both intravascular (i.e. mean pulmonary arterial pressure [Ppa] > 100 mmHg) and extravascular (e.g. negative inspiratory pressure swings) mechanisms. Objective: That inclined running would reduce breathing frequency (coupled to stride frequency) and increase tidal volume thus increasing lung volume changes and intrapleural pressure swings resulting in more pronounced EIPH. Methods: Six Thoroughbred horses were run to volitional fatigue (incremental step tes...
Lafortuna CL, Saibene F, Albertini M, Clement MG.Horses display remarkable aerobic capabilities, attaining during muscular exercise a maximal rate of oxygen consumption about 30-fold higher than the resting value, and 2.5-fold higher than that of other mammals of similar body mass. Under these circumstances an enormous mechanical burden is expected to impinge on the equine respiratory pump and regulatory mechanisms aiming to minimize this load may play an important role in determining the adequacy of the respiratory system to the metabolic requirements. The behaviour of the respiratory system has been investigated in horses at rest and durin...
Gehlen H, Bubeck K, Stadler P.In 12 healthy warmblood horses (six trained and six untrained) the pulmonary wedge pressure and heart frequency was measured at rest and during a standardised exercise test on a treadmill. The mean pulmonary wedge pressure at rest was 14.53 +/- 2.36 mmHg. There was no significant difference in pulmonary wedge pressure either at rest or during exercise between trained and untrained horses. During walking (1.8 m/s) the mean pulmonary wedge pressure was 19.62 +/- 4.03 mmHg, during trotting (4 und 5 m/s) it was between 22.38 +/- 3.92 mmHg and 25.28 +/- 3.7 mmHg. During canter (6 m/s) and gallop (8...
Butudom P, Axiak SM, Nielsen BD, Eberhart SW, Schott HC.Body mass (BM), water intake (WI), and plasma osmolality (P(osm)) and electrolyte concentrations were measured in six 2-year-old Arabian horses provided either 4 l, 8 l, or an unlimited amount of water (UW) for drinking during the initial 5 min of recovery from 45-km of treadmill exercise. After weighing, horses were placed in a stall and further WI between 20 and 60 min of recovery was measured. During exercise, horses lost 3.3+/-0.3%, 3.2+/-0.1%, and 3.3+/-0.2% (P>.05) of BM and P(osm) increased by 7.2+/-0.5, 7.9+/-0.8, and 7.7+/-0.5 mOsm/kg (P>.05) for 4 l, 8 l, and UW, respectively. ...
Ducharme NG, Hackett RP, Woodie JB, Dykes N, Erb HN, Mitchell LM, Soderholm LV.Contributes to the understanding of the pathogenesis of dorsal displacement of the soft palate during exercise so that management of this condition could be enhanced. Objective: That the thyrohyoid muscles play an important role in the stability of the laryngo-palatal relationship and that dysfunction of these muscles leads to dorsal displacement of the soft palate (DDSP) during exercise. Methods: Ten horses were exercised on a high-speed treadmill under 4 different treatment conditions: control conditions (n = 10), after resection of thyrohyoid muscles (TH, n = 10), after sham-treatment (n = ...
Franklin SH, Usmar SG, Lane JG, Shuttleworth J, Burn JF.It has long been recognised that the production of abnormal respiratory sounds by horses during exercise is frequently associated with upper airway obstructions. Respiratory acoustic measurements have shown promise in investigation of upper airway disorders in man and, more recently, in horses with experimentally-induced obstructions. Objective: To evaluate sounds from exercising horses with naturally occurring dynamic obstructions of the upper respiratory tract and to compare these with those from normal horses in order to determine whether different obstructions produce characteristic spectr...
Wickler SJ, Hoyt DF, Cogger EA, Myers G.Two studies have focused on potential triggers for the trot-gallop transition in the horse. One study concluded that the transition was triggered by metabolic economy. The second study found that it was not metabolic factors but, rather, peak musculoskeletal forces that determine gait transition speeds. In theory, peak musculoskeletal forces should be the same when trotting up an incline as when trotting at the same speed on the level. Assuming this is the case, we hypothesized that if peak forces determine gait transition speeds then horses should switch from a trot to a gallop at the same sp...
Frye MA, Bright JM, Dargatz DA, Fettman MJ, Frisbie DD, Baker DC, Traub-Dargatz JL.This study was done to determine whether administration of dobutamine would produce echocardiographic and electrocardiographic alterations comparable to those induced by treadmill exercise in healthy horses. Fourteen horses received maximal treadmill exercise and, separately, intravenous dobutamine infusion up to a maximum rate of 50 microg/kg/min. Ten of the 14 horses were euthanized, and the myocardial tissues were examined grossly and histopathologically. No significant differences were found in the chronotropic effects of dobutamine and exercise (P = .905). Dobutamine induced greater inter...
Manohar M, Goetz TE, Hassan AS.It is reported that preexercise hyperhydration caused arterial O(2) tension of horses performing submaximal exercise to decrease further by 15 Torr (Sosa-Leon L, Hodgson DR, Evans DL, Ray SP, Carlson GP, and Rose RJ. Equine Vet J Suppl 34: 425-429, 2002). Because hydration status is important to optimal athletic performance and thermoregulation during exercise, the present study examined whether preexercise induction of hypervolemia would similarly accentuate the arterial hypoxemia in Thoroughbreds performing short-term high-intensity exercise. Two sets of experiments (namely, control and hype...
Holcombe SJ, Cornelisse CJ, Berney C, Robinson NE.To determine whether the hyoepiglotticus muscle has respiratory-related electromyographic activity and whether electrical stimulation of this muscle changes the position and conformation of the epiglottis, thereby altering dimensions of the aditus laryngis. Methods: 6 Standardbred horses. Methods: Horses were anesthetized, and a bipolar fine-wire electrode was placed in the hyoepiglotticus muscle of each horse. Endoscopic images of the nasopharynx and larynx were recorded during electrical stimulation of the hyoepiglotticus muscle in standing, unsedated horses. Dorsoventral length and area of ...
Vervuert I, Coenen M, Wedemeyer U, Chrobok C, Harmeyer J, Sporleder HP.Physical exercise is known to affect calcium homeostasis in horses, but there is little information on the hormonal regulation of calcium metabolism during exercise. In order to evaluate the effects of exercise and training on calcium homeostasis and intact plasma parathyroid hormone, 7 untrained Standardbred horses were studied in a 6 week training programme. These horses were accustomed to running on the treadmill 3 weeks before onset of training and were exercised on a high-speed treadmill with an initial incremental standardised exercise test (SET 1: 6 incremental steps of 5 min duration e...
Lorenzo-Figueras M, Merritt AM.To assess effects of exercise on a treadmill with changes in gastric volume and pH in the proximal portion of the stomach of horses. Methods: 3 healthy adult horses. Methods: A polyester bag of approximately 1,600 mL was placed into the proximal portion of the stomach of each horse via a nasogastric tube. Changes in bag volume, determined by an electronic barostat, were recorded before, during, and after a training session on a treadmill with and without prior withholding of food. In separate experiments, pH in the proximal portion of the stomach was continuously recorded during exercise for f...
Parente EJ, Martin BB, Tulleners EP, Ross MW.To evaluate the occurrence of dorsal displacement of the soft palate (DDSP) during high-speed treadmill (HSTM) exercise in racehorses, and determine treatment efficacy relative to the endoscopic findings observed during resting and HSTM endoscopic examination. Methods: Retrospective study. Animals-Ninety-two racehorses (74 Thoroughbreds, 18 Standardbreds). Methods: The signalment, history (clinical and race), treatments, and video recordings made during resting and HSTM endoscopy were reviewed in 92 racehorses that developed DDSP during HSTM exercise. Only horses that completed 3 starts before...
Kingston JK, Bayly WM, Meyers KM, Sellon DC, Wardrop KJ.There is evidence that equine platelet reactivity is altered by strenuous exercise. Changes in platelet reactivity could impact haemostasis following exercise-induced injury and may play a role in the pathophysiology of exercise-induced pulmonary haemorrhage. Interpretation of results of previous studies is hindered by potential in vitro-induced changes in platelet activity through the choice of anticoagulant and the use of platelet inhibitors. The present study was undertaken to re-evaluate the effect of exercise on equine platelets using methodologies that minimise in vitro-induced changes i...
Durando MM, Martin BB, Hammer EJ, Langsam SP, Birks EK.The primary goal was to investigate the relationship between dynamic upper airway abnormalities and arterial blood gas tensions during exercise. Horses that completed a high-speed treadmill examination consisting of upper-airway videoendoscopy, blood gas evaluation and electrocardiogams and, postexercise, echocardiograms and tracheal washes, were included. An age-matched group of fit, healthy Thoroughbreds, trained to run on a high-speed treadmill, served as controls for blood gas values at specific exercise speeds. One hundred and nineteen horses completed the treadmill examination. Sixty (50...
Couroucé-Malblanc A, Pronost S, Fortier G, Corde R, Rossignol F.There are a variety of reasons for poor performance in racehorses. Exercise intolerance has often been associated with subclinical respiratory abnormalities, and diagnostic aids are therefore used to enhance clinical detection. Physiological variables can also be measured in order to evaluate the metabolic reponse to exercise. This study evaluated the relationship between physiological measurements and upper airway videoendoscopy during a standardised treadmill exercise test and bronchoalveolar lavage (BAL) cytology in control horses (good racing performance, n = 14) and poor performers (n = 2...
Beard LA, Hinchcliff KW.Sodium bicarbonate is often administered to horses before racing in an attempt to delay fatigue and improve performance. We examined the effect of acid-base status on serum ionised calcium concentration (iCa) during high intensity exercise in 8 Standardbred mares. In a randomised, blinded, cross-over study, mares were administered each of 3 treatments, NaCl (0.7 g/kg bwt), NaHCO3 (1 g/kg bwt) in 3 l water, or 3 l of water only, 4 h before performing a standardised exercise test to fatigue on a treadmill. Mixed venous blood samples were collected as the horses ran for 5 min at 3 m/s, to fatigue...
Foreman JH, Kneller SK, Twardock AR, Chambers MD, Inoue OJ.Scintigraphy has been used in numerous clinical settings to examine horses to determine the origin of lameness problems, but it has not been used previously to monitor prospectively the skeletal responses of a group of similarly-trained racehorses. Our hypothesis was that in naïve Thoroughbred (TB) racehorses, initial treadmill training induces increased radiopharmaceutical uptake in high-motion joints and in the dorsal third metacarpal bone (MC3). Eight previously-untrained TB racehorses underwent sequential skeletal scintigraphic examinations as they exercised daily for 9 weeks on an inclin...
Sloet van Oldruitenborgh-Oosterbaan MM, Annee MP, Verdegaal EJ, Lemmens AG, Beynen AC.Feeding a high-fat diet increases fat utilisation and may decrease glycogen utilisation resulting in a lower lactate production during moderate exercise. The effects of fat feeding on exercise- and lipid metabolism-associated blood variables were evaluated in 6 Standardbred horses during submaximal exercise. The horses were fed a high- (11.8% fat in total dietary dry matter) or a low-fat diet (1.5% fat) in a cross-over experiment with feeding periods of 4 weeks. At the end of each feeding period, the horses were subjected to a submaximal standardised stepwise exercise test on a treadmill. Bloo...
Jones JH, Cox KS, Takahashi T, Hiraga A, Yarbrough TB, Pascoe JR.We determined whether the caudodorsal region of the intrapleural space in exercising horses experiences larger pressure fluctuations than other regions and whether systematic phase-shifting of peak intrapleural pressures along the length of the thorax suggests the existence of locomotor-induced intrapleural pressure waves. We utilised percutaneous introducers and solid-state pressure-tip transducers implanted along the dorsal aspect of the thorax, mid-thorax or oesophagus to measure regional intrapleural pressures while 3 horses galloped on a flat treadmill at 13-14 m/s, then recorded pressure...
Robert C, Valette JP, Pourcelot P, Audigié F, Denoix JM.A thorough knowledge of the horse's back and limb movements at different speeds is important in the design of training programmes and the prevention of speed-related injuries. The objective of this study was to investigate changes in muscle activity and kinematics of the trot with increased speed. To evaluate these effects, 4 Saddlehorses were recorded while trotting on a horizontal treadmill at speeds ranging from 3.5-6.0 m/s. The 3-D trajectories of skin markers on the left side of the horse and the dorsal midline of the trunk were established. Electrical activity was obtained simultaneously...
Sewell DA, Harris RC.Adenine nucleotide (AN) degradation has been shown to occur during intense exercise in the horse and in man, at or close to the point of fatigue. The aim of the study was to compare the concentrations of muscle inosine 5'-monophosphate (IMP) and plasma ammonia (NH3) during intense exercise with the concentrations of muscle and blood lactate. Seven trained thoroughbred horses were used in the study. Each exercised on a treadmill for periods of between 30 s and 150 s, at 11 and/or 12 m.s-1. Blood and muscle samples were taken and analysed for lactate and NH3 and adenosine 5'-triphosphate (ATP), ...
Vincen TL, Newton JR, Deaton CM, Franklin SH, Biddick T, McKeever KH, McDonough P, Young LE, Hodgson DR, Marlin DJ.Heart rate is one of the most commonly measured variables in equine exercise physiology and relative exercise intensity commonly expressed as % of maximal heart rate. A number of influences affect maximal heart rate (HRmax), including age of the horse but other factors have not been described. Objective: To determine if fitness, health status, gender, breed, athletic use, body mass, in addition to age, are predictive of HRmax in the horse. Methods: Maximal heart rate data from 328 horses which underwent treadmill exercise tests at 5 different laboratories were obtained retrospectively. Univari...
Judy CE, Galuppo LD.To determine whether iatrogenic hemarthrosis of the metacarpophalangeal joint could be used as a model for temporary reversible joint pain in horses. Methods: 8 adult horses. Methods: Each horse was evaluated on a treadmill before and after injection of 1 metacarpophalangeal joint with 10 mL of autogenous blood. Horses were evaluated subjectively and objectively by use of a computerized force measurement system at intervals until lameness abated. The mean force difference between injected and noninjected limbs at all time periods after injection was compared with the difference between limbs a...
Kollias-Baker C, Cox K, Jones J.Omeprazole is a proton-pump inhibitor recently approved in the United States for the treatment of gastric ulcer disease in horses. A study was designed to determine the effects of omeprazole treatment on the physiological indices of performance of horses during incremental treadmill exercise. In a crossover-design study carried out over 2 weeks, five horses completed standardized incremental exercise tests on a high-speed treadmill either with no treatment or treatment with omeprazole. No statistically significant effects of omeprazole were found on the mean maximum responses for specific oxyg...
Williams CA, Carlucci SA.Vitamin E is the most commonly supplemented antioxidant in horses; however, previous research is not conclusive as to the recommended level for exercising horses. Objective: To evaluate the effects of 3 levels of vitamin E supplementation on oxidative stress and vitamin/antioxidant status in intensely exercised horses to determine the optimal level of vitamin E supplementation. Methods: Twelve unfit Standardbreds were divided into 3 groups, supplemented orally with 0 (CON), 5000 (MOD), or 10,000 (HI) iu/day of DL-alpha-tocopheryl acetate. The 3 x 3 Latin square design consisted of three 4 week...
Jones JH, Ohmura H, Stanley SD, Hiraga A.Human athletes run faster and experience fewer injuries when running on surfaces with a stiffness 'tuned' to their bodies. We questioned if the same might be true for horses, and if so, would running on surfaces of different stiffness cause a measurable change in the amount of energy required to move at a given speed? Objective: Different brands of commercial treadmills have pans of unequal stiffness, and this difference would result in different metabolic power requirements to locomote at a given speed. Methods: We tested for differences in stiffness between a Mustang 2200 and a Säto I comme...
Dart AJ, Dowling BA, Smith CL.To report dynamic collapse of the apex of the left corniculate process under the right corniculate process into the airway at the dorsal apposition of the paired arytenoid cartilages during exercise as a cause of upper airway dysfunction in horses. Methods: Retrospective study. Methods: Fifteen horses with a history of poor performance and/or upper respiratory tract noise during exercise. Methods: Video recordings of all horses referred for upper airway evaluation using high-speed treadmill videoendoscopy (HSTV) between January 1998 and December 2003 were reviewed. Records of horses that devel...
Pelletier N, Leith DE.Thoroughbred horses (TB) have no ventilatory response to added CO2 during near-maximal exercise. To see whether that reflects mechanical limits to ventilation or the control of breathing, we examined the effects of varying inspired O2 fraction (0.16, 0.21, or 0.30) in five normal TB standing quietly and galloping at 10 and 14 m/s on a level treadmill. We measured gas exchange (O2 consumption and CO2 production) and ventilation with a flow-through mask system. We also measured PO2, PCO2, and O2 contents in arterial and mixed venous blood and calculated cardiac output by using the Fick equation....
Olsen SC, Coyne CP, Lowe BS, Pelletier N, Raub EM, Erickson HH.Four hours prior to exercise on a high-speed treadmill, 4 dosages of furosemide (0.25, 0.50, 1.0, and 2.0 mg/kg of body weight) and a control treatment (10 ml of 0.9% NaCl) were administered IV to 6 horses. Carotid arterial pressure (CAP), pulmonary arterial pressure (PAP), and heart rate were not different in resting horses before and 4 hours after furosemide administration. Furosemide at dosage of 2 mg/kg reduced resting right atrial pressure (RAP) 4 hours after furosemide injection. During exercise, increases in treadmill speed were associated with increases in RAP, CAP, PAP, and heart rate...
Düsterdieck KF, Schott HC, Eberhart SW, Woody KA, Coenen M.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 ...
Golland LC, Evans DL, Stone GM, Tyler-McGowan CM, Hodgson DR, Rose RJ.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...
Kotschwar AB, Baltacis A, Peham C.Saddle pads are widely used in riding sports but their influence on saddle pressures is poorly understood. Objective: To evaluate the forces acting on the horse's back, and the eventual pressure distribution by using different saddle pads underneath a fitting saddle. Methods: Sixteen sound horses of different breeds and ages were ridden on a treadmill at walk and sitting trot. The horses were wearing a dressage saddle with a fitting saddle tree and 4 different saddle pads (gel, leather, foam and reindeer fur) successively. For comparison, measurements were made without any saddle pad. Right fo...
Licka T, Peham C, Zohmann E.The aim of this study was to establish basic reference data for evaluating 3-dimensional movement of the equine back at the trot. In 22 mature horses without any clinical signs of back pain, the movement of the back was measured during trotting on a treadmill with a system for motion analysis. The position of the markers placed on the head, hooves, skin above the spinous processes of T5, T10, T16, L3 and on 2 of the sacral spines was recorded. The results of all movements were expressed in percent of the horse's height at its withers. At the trot, the maximum lateral movement at the head was 1...
Sandersen C, Detilleux J, Art T, Amory H.Stress echocardiography could be a useful diagnostic test in horses suspected to suffer from exercise-induced myocardial dysfunction as a cause of exercise intolerance. Objective: To evaluate the effect of treadmill exercise and pharmacological stress test on left ventricular echocardiographic parameters. Methods: Echocardiography was performed in 2 groups of 5 healthy horses, either immediately after a near-maximal treadmill exercise (Group EXE) or during a pharmacological challenge (Group DOB) consisting of 35 microg/kg atropine, followed by incremental dobutamine infusion rates of 2-6 micro...
McKeever KH, McNally BA, Hinchcliff KW, Lehnhard RA, Poole DC.To test the hypotheses that erythropoietin (rhuEPO) treatment increases systemic hematocrit, maximal O2 uptake (VO2max, by elevated perfusive and diffusive O2 conductances) and performance five female horses (4-13 years) received 15 IU/kg rhuEPO (erythropoietin) three times per week for three weeks. These horses had been splenectomized over 1 year previously to avoid confounding effects from the mobilization of splenic red blood cell reserves. Each horse performed three maximal exercise tests (one per month) on an inclined (4°) treadmill to the limit of tolerance; two control trials and one f...
Manohar M.Previous studies of pulmonary vascular pressures have utilised gradual incremental step exercise protocols, but in competitive racing at the track, horses perform rapid acceleration high-intensity exercise. The rate of rise in pulmonary vascular pressures under conditions of quick onset high-intensity exercise is unknown. Catheter mounted manometers, whose in vivo signals were matched with pressure signals obtained via transducers connected to fluid-filled lumens from same cardiovascular sites, were used to compare right heart and pulmonary vascular pressures in 8 healthy Thoroughbreds perform...
Geor RJ, McCutcheon LJ, Hinchcliff KW, Sams RA.In several species, physical conditioning (training) provokes a large shift in substrate utilisation during submaximal exercise. Few studies in horses have quantitatively examined these effects. Therefore, the effects of exercise training on plasma glucose kinetics during submaximal exercise were examined in 7 horses (5 Thoroughbred, 2 Standardbred; age 3-9 years) that had been paddock-rested for at least 6 months. Two days after determination of maximum aerobic capacity (VO2max), horses ran on a treadmill (4 degree incline) at 55% of VO2max (UT) for 60 min or until fatigue and then completed ...
Arfuso F, Giannetto C, Giudice E, Fazio F, Panzera F, Piccione G.The aim of this study was to assess whether acid-base profile exhibits changes in regularly trained show jumping horses undergoing increasing exercise workloads. Seven female Italian saddle horses were subjected to three different physical exercise trials of increasing workload identified as three exercise phases (EPs). During EPI horses were subjected to a standardized exercise test consisting of 15 minutes of treadmill, during EPII horses were subjected to a show jumping test (height, 0.9-1.1 m; course length, 300 m), during EPIII horses underwent two jumping sessions carried out over two...
Bowers JR, Slocombe RF.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...
Treiber KH, Hess TM, Kronfeld DS, Boston RC, Geor RJ, Friere M, Silva AM, Harris PA.Glucose regulation is critical for health and exercise performance. Objective: To quantify the effects of exercise and diet on insulin sensitivity (SI), glucose effectiveness (Sg), acute insulin response to glucose (AIRg) and disposition index (DI) in horses. Methods: This study applied the minimal model of glucose and insulin dynamics to exercise-trained Arabian geldings during rest or constant moderate-intensity exercise after 8 weeks adaptation to feeds high in sugar and starch (SS, n = 6) or fat and fibre (FF, n = 6). Horses underwent 2 frequently sampled i.v. glucose tolerance tests (FSIG...
Buchholz BM, Murdock A, Bayly WM, Sides RH.The antifibrinolytic, 6-aminohexanoic acid, also named aminocaproic acid (ACA), has been used empirically as a treatment for exercise-induced pulmonary haemorrhage (EIPH) on the unsubstantiated basis that transient coagulation dysfunction may contribute to its development. Objective: To assess the effect of ACA on bronchoalveolar lavage fluid (BALF) erythrocyte counts in horses performing treadmill exercise at an intensity greater than that needed to reach maximal oxygen consumption. Methods: Eight Thoroughbreds were exercised to fatigue 3 times on a 10% inclined treadmill at a speed for which...
Willemen MA, Savelberg HH, Bruin G, Barneveld A.Toe weights are applied to influence the stride characteristics of trotters. The quantitative effect of 88-g toe weights on the stride characteristics of Standardbred trotters was evaluated in a kinematic study using a CODA-3 analysis system. Six trotters were studied at a speed of 11 m/s on a treadmill. Temporal gait variables, joint angles, and the trajectories of the forelimb hoof were calculated. The stride patterns of the individual trotters were assessed by a judge and compared to the CODA-output. Those trotters with poor flexion of the carpal joint during the swing phase or with insuffi...
Kang H, Zsoldos RR, Skinner JE, Gaughan JB, Mellor VA, Sole-Guitart A.The frequent monitoring of a horse’s body temperature post strenuous exercise is critical to prevent or alleviate exertional heat illness (EHI) from occurring. Percutaneous thermal sensing microchip (PTSM) technology has the potential to be used as a means of monitoring a horse’s body temperature during and post-exercise. However, the accuracy of the temperature readings obtained, and their relationship to core body temperature are dependent on where they are implanted. This study aimed to document the relationship between core body temperature, and temperature readings obtained using PTSM...
Kohn CW, Hinchcliff KW, McKeever KH.Six healthy Thoroughbred mares were trained to run on a high-speed treadmill and were conditioned for approximately 5 weeks. Each horse performed 6 identical standardised exercise tests (SET) 5 to 7 days apart. Each SET was performed under different ambient laboratory conditions: low temperature/low humidity (LL) 20.2 degrees +/- 0.6 degree C, 53.6 +/- 4.1%; low temperature/high humidity (LH) 19.7 +/- 0.6 degrees C, 86.7 +/- 4.2%; medium temperature/low humidity (ML) 24.6 +/- 0.2 degrees C, 58.7 +/- 3.7%; medium temperature/high humidity (MH) 24.7 +/- 0.3 degrees C, 87.5 +/- 1.4%; high tempera...
Hodgson DR, Rose RJ, DiMauro J, Allen JR.The effects of training on skeletal muscle composition were studied in four Standardbred geldings given a seven week submaximal treadmill training programme. Before the start of training, muscle biopsies were collected from the left middle gluteal muscle for the determination of muscle fibre types, oxidative capacity and capillary numbers using histochemical techniques. The concentrations of citrate synthase, 3-hydroxyacyl-CoA dehydrogenase (HAD), lactate dehydrogenase and total muscle glycogen were measured using fluorometric methods. Muscle biopsy samples were repeated after one, three, five...
Sloet van Oldruitenborgh-Ooste , Barneveld A, Schamhardt HC.To evaluate the effects of uphill trotting on stride characteristics, 6 well trained Dutch Warmblood horses trotted at 4 m/s on a horizontal and on an inclined (6%) treadmill. This was done under 3 different conditions, unloaded, mounted by an experienced 90 kg rider and loaded with 90 kg of lead, to study whether extra weight provoked more or different alterations than the incline per se. In all 3 test situations (unloaded, mounted and lead-loaded), heart rates were significantly higher on the inclined treadmill than on the horizontal treadmill. Stride duration tended to increase on the incli...
Erickson BK, Erickson HH, Coffman JR.Intravenous frusemide (1.0 mg/kg bwt) or phentolamine (0.33 mg/kg bwt) was given to 7 horses 1 h before exercise and their effects on pulmonary artery and aortic pressure changes during strenuous exercise were examined. Short-term near-maximal treadmill exercise (10 m/sec, 3 degrees incline) produced increases in heart rate, mean pulmonary artery pressure (PAP), mean aortic pressure (AP), and packed cell volume (PCV). Frusemide did not affect heart rate, PAP or PCV during exercise. Frusemide significantly decreased mean AP by 10 to 15 mmHg during exercise. Phentolamine produced an increase in ...
Garrett KS, Woodie JB, Embertson RM.Assessment of arytenoid movement has traditionally been performed using upper airway (UA) endoscopy. However, recent work suggests that laryngeal ultrasonography may provide additional complementary information. Objective: To determine the value of laryngeal ultrasonography for the diagnosis of recurrent laryngeal neuropathy in the horse. Objective: Horses with abnormal arytenoid movement (AM) during treadmill UA endoscopy would have increased echogenicity of the left cricoarytenoideus lateralis muscle (CALM) and smaller left CALM and vocalis size while horses with normal AM during treadmill U...
Vengust M, Stämpfli H, De Moraes AN, Teixeiro-Neto F, Viel L, Heigenhauser G.Carbonic anhydrase (CA) catalyses the hydration/dehydration reaction of CO(2) and increases the rate of Cl(-) and HCO(3)(-) exchange between the erythrocytes and plasma. Therefore, chronic inhibition of CA has a potential to attenuate CO(2) output and induce greater metabolic and respiratory acidosis in exercising horses. Objective: To determine the effects of Carbonic anhydrase inhibition on CO(2) output and ionic exchange between erythrocytes and plasma and their influence on acid-base balance in the pulmonary circulation (across the lung) in exercising horses with and without CA inhibition....
Art T, Duvivier DH, van Erck E, de Moffarts B, Votion D, Bedoret D, Lejeune JP, Lekeux P, Serteyn D.In equine sports medicine, VO2 has been measured exclusively with stationary systems, in laboratories equipped with a treadmill. Measurement during exercise in field conditions has not previously been reported because of the lack of portable equipment designed for horses. Objective: A commercially available portable metabolic measurement system, based on breath-to-breath gas analysis and flow spirometry, was adapted to the horse's physiology and morphology (Cosmed K4b2 and Equimask) and its validity tested by (1) repeatability of the measures and (2) comparing metabolic data to those obtained ...
