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.
Eaton MD, Evans DL, Hodgson DR, Rose RJ.We examined the effect of treadmill speed and incline on O2 uptake (VO2), CO2 production, heart rate (HR), plasma lactate concentration, economy of locomotion, stride frequency, and stride length. A further aim was to examine the relationships between HR and VO2 and lactate and VO2 and whether these relationships vary with alterations in treadmill incline. The experiment was a latin square design, using five horses and five treadmill inclines (0, 2.5, 5.0, 7.5, and 10.0%). Fit Thoroughbred horses exercised for 4 min at 3 m/s at 0% slope, after which the treadmill was set to the allocated incli...
Buchner HH, Savelberg HH, Schamhardt HC, Barneveld A.The kinematic pattern of mild bilateral lameness was studied by inducing a supporting limb lameness in both fore-limbs of 11 sound Dutch Warmblood horses. The kinematics of the horses were recorded while they trotted (3.5 m/s) on a treadmill. The locomotion analysis system CODA-3 was used to determine the temporal stride patterns, limb movements as well as head and trunk movement patterns. The transient lameness model, by which pressure-induced pain is evoked on the hoof sole, was used. Differences between left and right limbs as well as between the sound and the lame condition were tested usi...
Sloet van Oldruitenborgh-Oosterbaan MM, Barneveld A.Six Dutch warmblood horses, ridden by an experienced rider, cantered 3320 m at a speed adapted to the individual horse's anaerobic threshold, under four different conditions: 1, on a firm shell track with the speed varying from 6.5 to 9.4 m/s; 2, on a horizontal treadmill at the same speeds and for the same duration as in test 1; 3, on a horizontal treadmill for the same duration as in tests 1 and 2, but at a 10 per cent higher speed; and 4, on a treadmill at the same speed and for the same duration as in test 1, but at an inclination of 1 to 2 per cent adjusted individually to obtain heart ra...
Maisi P, Paananen M, Koivunen AL.Seventeen trotters, eight healthy and nine with a mild respiratory disease, underwent a submaximal treadmill exercise. Heart rate, breathing frequency, intrapleural pressure difference (IP difference) as well as haematocrit and concentration of lactic acid in blood were monitored before exercise, during exercise and during recovery. The activities of beta-glucuronidase and plasmin, total proteolytic activity and trypsin inhibitory capacity were measured from the tracheal fluid before and after exercise. IP difference significantly increased during exercise and returned to normal values within ...
Taylor LE, Ferrante PL, Kronfeld DS, Meacham TN.Seven Arabian horses performed a standard incremental exercise test on a high-speed treadmill at 6% slope then were randomly assigned to two diets, a control diet of ground hay and concentrates and a similar diet with 10% added fat (by weight). Horses were sprint-trained 4 d/wk, and two additional exercise tests were performed at 5-wk intervals. Heart rates and rectal temperatures were monitored and venous blood samples were collected at rest and at each speed increment. Whole blood was analyzed for glucose, lactate, and hemoglobin concentrations, and plasma was analyzed for pH, pCO2, albumin,...
Back W, Schamhardt HC, Hartman W, Bruin G, Barneveld A.The gait of 24 horses was recorded on a treadmill when they were trotting at 4 m sec-1, first when they were four months old and again when they were 26 months. The data recorded at four months were used to predict the locomotion of the adult horses, and the predictions were assessed against the data recorded at 26 months. The locomotion of the foals and the adults appeared to be closely related, when the differences in segment length and joint angles due to growth were taken into account. The duration of swing, the total range of protraction and retraction, and the maximum tarsal flexion coul...
Pan LG, Forster HV, Wurster RD, Brice AG, Lowry TF.In three previously reported studies, we had documented that the normal exercise hyperventilation in ponies is accentuated by carotid body denervation (CBD), not affected by hilar nerve pulmonary vagal denervation (HND), and mildly attenuated by spinal cord ablation of the dorsal lateral columns at L2 (SA). In the present study, we hypothesized that if redundancy of control existed in exercising ponies, then multiple denervations of theoretically important pathways in the same animal might attenuate the ventilatory response to exercise in a way not predictable by the individual lesion experime...
Gottlieb-Vedi M, Persson S, Erickson H, Korbutiak E.The purpose of this study was to determine if training with short intervals at the velocity producing a lactate level of 4 mmol/l (VLA4) is sufficient to induce adaptations and better exercise tolerance. Five Standardbred mares (4-8 years) were interval trained on a treadmill 3 days a week for 12 weeks and subsequently detrained for 4 weeks. Standardized exercise tests were performed before, during and after the training period and muscle biopsies were taken. Measurements were made of heart rate, oxygen consumption, stride frequency, blood volume and blood lactate. Plasma volume was reduced af...
Kokkonen UM, Hackzell M, Räsänen LA.To study the exercise-induced changes in atrial natriuretic peptide (ANP), a hormone with cardiovascular and renal effects, an incremental submaximal exercise test on a high-speed treadmill was carried out with Standardbred and Finnhorse trotters, the former bred for speed and the latter originally for heavy work. Standardbreds performed the 2 min exercise intervals at speeds of 6, 7, 8, 9 m s-1 and Finnhorses, according to their training status, at 5, 6, 7, 8 m s-1, 4, 5, 6, 7 m s-1 or 5, 6, 7 m s-1. Steady-state heart rate (HR) was reached within each 2 min interval. The increase in HR was l...
Eaton MD, Evans DL, Hodgson DR, Rose RJ.Thoroughbred horses have a high aerobic capacity, approximately twice that of elite human athletes. Whereas the aerobic capacity of horses can be accurately measured, there have been no measurements of anaerobic capacity. The aim of this study was to determine whether maximal accumulated O2 deficit (MAOD) could be measured in horses and used as an estimate of anaerobic capacity, as in human athletes. Six fit Thoroughbred horses were used with the exercise protocol utilizing a treadmill set at a 10% incline. O2 uptake VO2 was measured via an open-flow system for seven submaximal speeds (3-9 m/s...
Gauvreau GM, Staempfli H, McCutcheon LJ, Young SS, McDonell WN.A standardized treadmill test was used to compare metabolic and ventilatory measurements between 10 standardbred racehorses. The horses were divided into two groups: group A (n = 5) had mean racing speeds of 4.4 s faster than group B (n = 5) over a 1-mi. distance. Each horse was fitted with a venous catheter and connected to a valved gas-collection system. The exercise test consisted of 1-min incremental workloads ranging from 4.0 to 12.0 m/s at a treadmill incline of 3 degrees. Group A had significantly higher (P < 0.05) measurements of maximal O2 consumption (VO2max), O2 pulse, and tidal ...
Kannegieter NJ, Dore ML.Endoscopy of the upper respiratory tract was performed in 100 horses during high speed treadmill exercise. Reasons for endoscopy were a history of an abnormal noise during exercise in 75 horses, poor performance in 17 horses and to evaluate the results of upper respiratory tract surgery in 8 horses. Of the 75 horses with a history of an abnormal noise during exercise the cause was determined in 67 (89%). Endoscopic abnormalities were detected at rest in 40 of these 75 horses (53%). In these 40 horses, a similar diagnosis as to the cause of the abnormal noise was made at rest and during exercis...
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....
Schott HC, Hodgson DR, Bayly WM.The effects of exercise on urinary excretion of red blood cells, pigments (haemoglobin and myoglobin) and protein were studied in 8 mares performing treadmill exercise at speeds eliciting 40, 60 and 95% of the maximal oxygen consumption (VO2max). Gross haematuria and pigmenturia were observed in all horses during exercise at the 2 higher intensities, while these findings were detected in only one of 8 mares during exercise at 40% of the VO2max. For the remaining 7 mares exercised at 40% of the VO2max, increased urinary excretion of red blood cells (RBCs) and pigments was evident after centrifu...
Back W, Schamhardt HC, Savelberg HH, van den Bogert AJ, Bruin G, Hartman W, Barneveld A.Kinematic data of the equine hind limb are presented graphically and related to functional aspects of the hind limb in locomotion. The trot of 24 two-year-old Dutch Warmblood horses was recorded at 4 m/s on a high-speed treadmill using kinematic analysis equipment. Joint angle-time, angle-angle, stick and marker diagrams were used to present graphically the data following standardised procedures. As the kinematic data were expressed with reference to the joint angles of the horse standing squarely and were time-standardised to the duration of the stride cycle, mean joint curves for the total g...
Mitten LA, Hinchcliff KW, Pate JL, Kohn CW, McKeever KH.Exertion has an effect on plasma, serum, and/or urine prostanoid concentrations in many species. We investigated the effect of exercise intensity on plasma prostaglandin concentrations during and after exercise in horses. Six Thoroughbreds completed 4 trials: 3 exercise trials (low-, medium-, and high-speed) and 1 nonexercise (control) trial on a high-speed treadmill. Blood samples were collected from a jugular catheter before, during, and after exercise. The PCV and blood lactate, plasma protein, plasma prostacyclin (6-keto-PGF1 alpha), thromboxane B2 (TXB2), and prostaglandin E2 (PGE2) conce...
Ehrlich PJ, Seeherman HJ, Morris E, Kolias C, Cook WR.The effect of left recurrent laryngeal neuropathy (LRLN) on the metabolic cost of locomotion (MCL) and peak aerobic power (VO2peak) was evaluated in four trained Thoroughbred racehorses. Oxygen consumption (VO2), carbon dioxide production (VCO2), venous lactate concentrations (LAC), and heart rate (HR) were measured during a treadmill exercise test (TET). Each horse performed the exercise test four times, alternating between normal upper airway function and reversibly induced LRLN. Subcutaneous infusion of 2% mepivicaine, a local anesthetic, into the region were the left recurrent laryngeal ne...
Back W, Schamhardt HC, Savelberg HH, van den Bogert AJ, Bruin G, Hartman W, Barneveld A.The kinematics of 24 two-year-old Dutch Warmblood horses were recorded at the trot (4 m/s) on a high-speed treadmill to study the coordination of joints within the equine forelimb. Joint angle-time, angle-angle, stick, and marker diagrams were used to show forelimb motion graphically. Because the kinematic data referred to the joint angles of the horse standing squarely and were time-standardised to the duration of the stride cycle, mean joint curves could be calculated for the total group. The motion of each segment in the equine forelimb during a complete stride is described and its function...
Holcombe SJ, Beard WL, Hinchcliff KW, Robertson JT.The effect of transection of the sternothyroideus and sternohyoideus muscles on upper airway mechanics was investigated in exercising horses. Upper airway mechanics of six Standardbred horses were measured at rest and during exercise before and 24 h and 2 wk after sternothyrohyoid myectomy. Transnasal tracheal and pharyngeal catheters connected to differential pressure transducers were used to measure tracheal and pharyngeal pressures. A pneumotachograph mounted on the rostral end of an airtight face mask was used to measure airflow. Horses ran at 50, 75, and 100% of maximal O2 consumption on ...
Art T, Franchimont P, Lekeux P.Ten horses underwent a standardised strenuous treadmill exercise test, before, during and after which measurements were made of plasma beta-endorphin and cortisol concentrations, blood lactate, glucose, haemoglobin and pH, the activities of creatine kinase, lactate dehydrogenase and aspartate amino-transferase, and heart rate, oxygen uptake and expired minute volume. The correlations between the exercise-induced response of beta-endorphin and the changes observed in the other physiological measurements were examined. There was a large variation in the beta-endorphin response of the horses to e...
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...
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...
Manohar M, Goetz TE, Hutchens E, Coney E.Right atrial, pulmonary artery, pulmonary capillary, pulmonary artery wedge, and systemic blood pressures of strenuously exercising horses increase markedly. As a consequence, myocardial metabolic O2 demand in exercising horses must be high. Experiments were, therefore, carried out on 9 healthy, exercise-conditioned horses (2.5 to 8 years old; 481 +/- 16 kg) to ascertain the regional distribution of myocardial blood supply in the atria and ventricles at rest and during exercise. Blood flow was measured, using 15-micron-diameter radionuclide-labeled microspheres that were injected into the left...
Mueller PJ, Jones MT, Rawson RE, van Soest PJ, Hintz HF.Oxygen consumption (VO2) and concentration of venous blood metabolites were measured in donkeys trained to run and to pull loads on a treadmill. VO2 in two donkeys running at maximal speed on a 9.8% slope was 110 +/- 2 ml.min-1.kg-1, approximately 22 times preexercise VO2. Average heart rate at maximal VO2 (VO2max) was 223 +/- 2 beats/min, five times the preexercise heart rate. Blood lactate increased 14-fold, and blood glucose did not change (P > 0.05). Animals running up a 4% incline and incremental draft loading of five donkeys walking on the level were also studied. The total energy cost o...
Linford RL.Quantitated locomotion analysis is increasingly being used during assessment and treatment of gait disorders in human beings. Locomotion analysis is also thought to have potential for enhancing the assessment of lameness in horses. Availability of high-speed video recording systems has simplified the process of quantitated locomotion analysis; however, the high cost of such systems has limited their use for routine clinical assessment in horses. The temporal resolution of 500- to 1,000-images/s (Hz) recording systems is beyond what has been considered necessary for precise quantitation of shor...
Kayar SR, Hoppeler H, Jones JH, Longworth K, Armstrong RB, Laughlin MH, Lindstedt SL, Bicudo JE, Groebe K, Taylor CR.The mean minimal transit time for blood in muscle capillaries (tc) was estimated in six species, spanning two orders of magnitude in body mass and aerobic capacity: horse, steer, dog, goat, fox and agouti. Arterial (CaO2) and mixed venous (CvO2) blood O2 concentrations, blood hemoglobin concentrations ([Hb]) and oxygen uptake rates were measured while the animals ran on a treadmill at a speed that elicited the maximal oxygen consumption rate (VO2max) from each animal. Blood flow to the muscles (Qm) was assumed to be 85% of cardiac output, which was calculated using the Fick relationship. Total...
Evans DL, Silverman EB, Hodgson DR, Eaton MD, Rose RJ.The relationship between gait and the respiratory response to exercise was examined in five standardbred racehorses which exercised on a treadmill at a pace and a gallop. After an initial warm-up, respiratory rate and stride frequency were measured after one and two minutes of treadmill exercise at 80 per cent of maximal oxygen consumption (VO2max), after one minute at 100 per cent VO2max and after two minutes at 100 per cent VO2max (galloping horses only). Exercise at 100 per cent VO2max continued until the horses showed signs of fatigue. Arterial blood was collected during exercise and when ...
Hjertén G, Drevemo S.The initial forelimb loading of a horse trotting at 3.7 ms-1 on a treadmill was studied by use of an instrumented shoe, accelerometers and high-speed cinematography. At the beginning of the stance phase the forelimb was loaded successively from the hoof. This is suggested to be an important factor for effective shock force absorbency in the extremities. Shearing forces may appear in the carpus before the onset of the longitudinal loading of the limb. These forces are proposed to depend on speed, locomotion pattern and the friction and hardness of the surface. It is suggested that shearing forc...
Howard RD, McIlwraith CW, Trotter GW, Powers BE, McFadden PR, Harwood FL, Amiel D.Bilateral osteochondral defects (10 mm2 x 3 mm deep) were created on the distal articular surface of the radial carpal bone of ten, 2- to 3-year-old horses. One defect of each horse was repaired, using a sternal cartilage autograft (treated), and the other was left untreated (control). The horses were exercised on a high-speed treadmill at incrementally increased speed and duration over the course of 12 months. Horses were evaluated arthroscopically at 6 to 7 weeks, and clinical examinations were conducted weekly at exercise. Twelve months after surgery, carpuses of each horse were radiographe...
King CM, Evans DL, Rose RJ.Various cardiorespiratory and metabolic indices were assessed during treadmill exercise in Thoroughbred and Standardbred racehorses with T wave changes in 4 or more leads on the electrocardiogram or second-degree atrio-ventricular (AV) block, and in horses that had no abnormalities on clinical examination, resting electrocardiography or upper respiratory tract endoscopy. No significant differences in heart rate, plasma lactate concentration, arterial blood gases, oxygen uptake, run time, peak velocity, or blood and red cell volumes were found between normal horses and horses with T wave change...
Marlin DJ, Scott CM, Mills PC, Louwes H, Vaarten J.The administration of 41 of an isotonic, plasma-like oral rehydration solution (ORS) with an osmotic skeleton and 41 of water (water; no osmotic skeleton), were evaluated in five thoroughbred horses. Solutions were administered by nasogastric tube 4 h after feeding. Uptake of deuterium, concentrations of plasma sodium, potassium, chloride, glucose, total protein and packed cell volume, pH, PCO2, HCO3-, total CO2, actual base excess, standard base excess, plasma volume and weight loss were assessed both at rest, and during and after exercise on a treadmill. Each horse underwent four experimenta...
Rugh KS, Garner HE, Miramonti JR, Hatfield DG.Myocardial and haemodynamic responses to strenuous treadmill exercise were monitored with chronically implanted instrumentation in seven physically untrained ponies. In two other ponies, haemodynamics were monitored using a conventional catheter technique. During exercise (mean +/- sem heart rate = 203 +/- 3 beats/min), left ventricular peak systolic ahd end-diastolic blood pressure significantly increased from 125 +/- 2 to 208 +/- 6 mmHg and from 29 +/- 1 to 58 +/- 3 mmHg, respectively (P less than 0.05). Peak positive first derivative of left ventricular pressure (dP/dt) was also increased s...
Fey K.Horses are obligate nasal breathers and depend on patency of their nasal passages. Several dynamic obstructive diseases in the pharyngeal and laryngeal area can be differentiated by high speed treadmill endoscopy and may be responsible for impaired exercise tolerance in the equine athlete. The anatomical specialty of guttural pouches predisposes the horse to species-specific diseases.
Burn JF, Portus B, Brockington C.The equine carpus has a well-defined limit to joint extension at approximately 180 degrees . During locomotion however, the carpus hyperextends during stance phase. Hyperextension is resisted by the carpal bones and ligaments, and it has been proposed that large increased hyperextension might relate to potentially damaging stress levels in the carpus. The aim of this study was to investigate the relationship between peak hyperextension of the carpus (PCE) and speed during locomotion on the level and on an incline. Five Thoroughbred horses were exercised on a treadmill at speeds between 1.8 and...
Powers SK, Beadle RE, Lawler J, Thompson D.The O2 deficit-O2 debt relationship in ponies was examined at two levels of treadmill exercise. Five healthy ponies exercised for 8 min at two work rates (WR):(1) 50 m/min at 6% grade and (2) 70 m/min at 12% grade. The O2 deficit and O2 debt were calculated using open-circuit measurement of pulmonary gas exchange during the transition from rest to steady-state exercise and during recovery from exercise. The O2 deficit was significantly lower (P less than 0.05) than the O2 debt at each of the two work rates. The means (+/- SEM) for the deficit and the O2 debt, respectively, in liters were: (1) ...
Manohar M, Duren SE, Sikkes BP, Day J, Baker JP.Tracheal, bronchial, and renal flow were studied in 8 healthy ponies at rest and during exercise performed on a treadmill at a speed setting of 20.8 km/h and 7% grade (incline) for 30 minutes. Blood flow was determined with 15-microns-diameter radionuclide-labeled microspheres that were injected into the left ventricle when the ponies were at rest, and at 5, 15, and 26 minutes of exertion. Heart rate and mean aortic pressure increased from resting values (40 +/- 2 beats/min and 124 +/- 3 mm of Hg, respectively) to 152 +/- 8 beats/min and 133 +/- 4 mm of Hg at 5 minutes of exercise, to 169 +/- ...
Gottlieb-Vedi M, Essén-Gustavsson B, Lindholm A.Five Standardbred trotters performed treadmill exercise with incrementally increasing trotting velocities for 2 min intervals in three different tests until fatigue. Each test was performed with draught loads of either 10, 20 or 30 kilopond (kp). Each trotting interval was followed by 2 min periods at a walk without draught load. Recordings were made of heart rate (HR), respiratory rate (RR), plasma lactate (PLA) and stride frequency (SF) at the end of each trotting interval. The HR increased to average values of 191 +/- 10,203 +/- 10 and 214 +/- 7 bpm and PLA increased to 3.8 +/- 0.7, 7.3 +/-...
Treiber KH, Geor RJ, Boston RC, Hess TM, Harris PA, Kronfeld DS.Advances in modeling and tracer techniques provide new perspective into glucose utilization and potential consequences to health or exercise performance. This study used stable isotope and compartmental modeling to evaluate how adaptation to a feed high in sugar and starch (SS) compared with a feed high in fat and fiber (FF) affects glucose kinetics at rest and during exercise in horses. Six trained Arabians adapted to each feed underwent similar tests at rest and while running approximately 4 m/s on a treadmill. For both tests, horses received 100 micromol/kg body weight [6,6-(2)H]glucose thr...
The Journal of nutritionDecember 1, 1993
Volume 123, Issue 12 2152-2157 doi: 10.1093/jn/123.12.2152
Lawrence L, Soderholm LV, Roberts A, Williams J, Hintz H.Four standardbred horses were used in a Latin square design experiment to evaluate the effects of feeding status on metabolic response to exercise. Horses were deprived of food overnight and then fed 0 (control condition), 1, 2 or 3 kg of corn grain approximately 2.5-3 h before exercise. The exercise test consisted of a warm-up phase (heart rate mean = 144 beats/min) followed by 800 m of walking and then a high intensity work bout for 1600 m (heart rate mean = 206 beats/min). All tests were conducted on a high speed equine treadmill on which the horses had been previously conditioned. During e...
Bröjer J, Jonasson R, Schuback K, Essén-Gustavsson B.The purpose was to investigate the degradation of proglycogen and macroglycogen in skeletal muscle during intense exercise. Ten Standardbred trotters performed a maximal treadmill exercise test comprising a warm-up period, an exercise period, starting at 7 m/s with increments of 1 m/s every 60 s until the onset of fatigue (mean +/- s.d. 246 +/- 32 s) and a walking recovery period. Muscle biopsies were taken at rest, immediately after exercise and 15 min postexercise. The exercise caused a marked anaerobic metabolism as shown by the decrease in both muscle ATP and creatine phosphate and increas...
McKeever KH, Scali R, Geiser S, Kearns CF.The purpose of the present study was to determine whether the training-induced hypervolaemic response seen in the horse is associated with aldosterone-mediated renal mechanisms affecting sodium conservation during the first days of training. Five healthy, Standardbred mares (weight 450-500 kg, age 4-8 years) that were unfit, but accustomed to running on the treadmill, were used to test the hypothesis that repeated submaximal exercise would alter plasma aldosterone (ALDO) concentration and renal excretion of electrolytes in horses within the first 3 days of training. The experiment consisted of...
Bröjer JT, Essén-Gustavsson B, Annandale EJ, Valberg SJ.To determine concentrations of proglycogen (PG), macroglycogen (MG), glucose, and glucose-6-phosphate (G-6-P) in skeletal muscle of horses with polysaccharide storage myopathy (PSSM) before and after performing light submaximal exercise. Methods: 6 horses with PSSM and 4 control horses. Methods: Horses with PSSM completed repeated intervals of 2 minutes of walking followed by 2 minutes of trotting on a treadmill until muscle cramping developed. Four untrained control horses performed a similar exercise test for up to 20 minutes. Serum creatine kinase (CK) activity was measured before and 4 hou...
Bayly WM, Slocombe RF, Weidner JP, Schott HC, Hodgson DR.The influences of facial airflow, exercise and wearing a facemask on gas exchange and upper airway (Pu), transpulmonary (PTP) and transdiaphragmatic (PTD) pressures were investigated in 6 horses performing an incremental exercise test on an inclined (10%) treadmill. The test consisted of a 2 min walk followed by two 2 min exercise bouts at intensities which produced 40% and 80% of maximal oxygen consumption. Horses performed the test 4 times, once for each of 4 protocols, which involved not wearing a facemask (A), wearing a mask with either no biased flow through it (B), with an expiratory bia...
Holcombe SJ, Berney C, Cornelisse CJ, Derksen FJ, Robinson NE.To determine the effect of a commercially available nasal strip on airway mechanics in exercising horses. Methods: 6 horses (5 Standardbreds and 1 Thoroughbred). Methods: Horses exercised on a treadmill at speeds corresponding to 100 and 120% of maximal heart rate with and without application of a commercially available nasal strip. Concurrently, tracheal pressures, airflow, and heart rate were measured. Peak inspiratory and expiratory tracheal pressures, airflow, respiratory frequency, and tidal volume were recorded. Inspiratory and expiratory airway resistances were calculated by dividing pe...
Rankins EM, Salem K, Manso Filho HC, Malinowski K, McKeever KH.Clenbuterol (β agonist) is a commonly administered bronchodilator in race and performance horses. While long-term administration can alter exercise performance and muscle properties, little is known about its effects on these parameters following short-term administration. A single dose of clenbuterol (0.80 µg/kg) was expected to alter muscle activity of the extensor carpi radialis, semitendinosus, and longissimus dorsi during submaximal exercise. Eight mature Standardbred horses exercised for 2 minutes at 5 m/s on a high-speed treadmill following clenbuterol dosing (clenbuterol) or no dosin...
Beard WL, Holcombe SJ, Hinchcliff KW.To determine the effect of a tongue-tie on upper airway mechanics in clinically normal horses exercising on a treadmill following sternothyrohyoid myectomy. Methods: 6 Standardbreds. Methods: Upper airway mechanics were measured with horses exercising on a treadmill at 5, 8, and 10 m/s 4 weeks after a sternothyrohyoid myectomy was performed. Pharyngeal and tracheal inspiratory and expiratory pressures were measured by use of transnasal pharyngeal and tracheal catheters connected to differential pressure transducers. Horses were fitted with a facemask and airflow was measured by use of a pneumo...
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...
Erickson BK, Forster HV, Pan LG, Lowry TF, Brown DR, Forster MA, Forster AL.We investigated changes in arterial PCO2 (PaCO2) and pulmonary ventilation (VE) in normal, carotid chemoreceptor-denervated, and hilar nerve-denervated ponies during intravenous lactic acid infusion at rest and treadmill exercise at 1.8 mph-5% grade (mild) and 1.8 mph-15% grade (moderate). Lactic acid, (0.5 M) infusion of 0.10, 0.13, and 0.20 ml.min-1.kg-1 at rest and mild and moderate exercise increased arterial [H+] linearly throughout the 10 min of acid infusion. At 10 min of infusion, arterial [H+] had increased approximately 20 nmol/l (0.2 pH units) for each condition and group. Under mos...
Wijnberg ID, van Dam KG, Graaf-Roelfsema Ed, Keizer HA, van Ginneken MM, Barneveld A, Breda Ev, van der Kolk JH.Too intensive training may lead to overreaching or overtraining. To study whether quantitative needle electromyography (QEMG) is more sensitive to detect training (mal)adaptation than muscle enzyme activities, 12 standardbred geldings trained for 32 wk in age-, breed-, and sex-matched fixed pairs. After a habituation and normal training (NT) phase (phases 1 and 2, 4 and 18 wk, respectively), with increasing intensity and duration and frequency of training sessions, an intensified training (IT) group (phase 3, 6 wk) and a control group (which continued training as in the last week of phase 2) w...
Fretheim-Kelly Z, Fjordbakk CT, Fintl C, Krontveit R, Strand E.Bits have often been incriminated as a cause of upper respiratory tract obstruction in horses; however, no scientific studies are available to confirm or refute these allegations. Clinical signs of dynamic laryngeal collapse associated with poll flexion (DLC) are induced when susceptible horses are ridden or driven into the bit. Objective: To determine whether use of Dr Cook's™ Bitless Bridle, instead of a conventional snaffle bit bridle, would reduce the severity of DLC in affected horses measured objectively using inspiratory tracheal pressures. Methods: Intervention study using each horse...
Foreman JH, Grubb TL, Benson GJ, Frey LP, Foglia RA, Griffin RL.This study was designed to characterise the acid-base and electrolyte effects of shortening the distance required during steeplechase (Phase B) in the face of hot and humid weather conditions during a treadmill-simulated Speed and Endurance test. Eight conditioned Thoroughbred horses underwent 3 randomised permutations of a standardised exercise test on a high speed treadmill. Each test consisted of trotting at 3.7 m/s for 10 min (Phase A); galloping at 11 m/s (Phase B) for 4 (cool laboratory conditions), 3 (hot and humid), or 2 (hot and humid) min; trotting at 3.7 m/s for 30 min (Phase C); an...
Fitzharris LE, Franklin SH, Allen KJ.There is very limited published information on the prevalence and significance of abnormal breathing patterns adopted during canter/gallop. Objective: The aim of this study was to report the prevalence of abnormal breathing patterns during canter/gallop and to investigate whether these may be associated with dynamic upper respiratory tract (URT) obstructions. Methods: Retrospective analysis of clinical records. Methods: Simultaneous audio and URT videoendoscopy recordings from 365 horses referred for treadmill evaluation were analysed. Results: Thirty percent of horses had an abnormal breathin...
Glycogen in skeletal muscle is a major source of energy during exercise and an important determinant of endurance capacity, so that its measurement may provide a meaningful marker of athletes' preparation and a possible predictor of performance, both in humans and in equines. Gold standard of glycogen concentration measurement is the histochemical and biochemical analysis of biopsy-derived muscle tissue, an invasive and potentially injuring procedure. Recently, high-frequency ultrasound (US) technology is being exploited in human sports medicine to estimate muscle glycogen content. Therefore, ...
Lindberg JE, Essén-Gustavsson B, Dahlborn K, Gottlieb-Vedi M, Jansson A.High starch intakes increase the risk for metabolic disorders and therefore alternative feedstuffs are of interest. High-fat oat varieties have a lower starch and higher energy content than regular oats and may therefore be useful in this context. Objective: Feeding high fat oats causes no adverse effects on the response to exercise and that the total amount of oats offered could be reduced compared to feeding with regular oats. Methods: Twelve Standardbred trotters were fed regular oats (diet C), high-fat oats (F), and a mixture (50:50) of C and F (M), together with haylage (30:70), in a Lati...
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...
Back W, van den Bogert AJ, van Weeren PR, Bruin G, Barneveld A.To get an in-depth insight into the ontogeny of the equine locomotor apparatus, the locomotion of 28 Dutch Warmblood foals was recorded at the walk, trot and canter on a treadmill using a CODA-3 apparatus. A great similarity in joint angle-time diagrams was found, although considerable differences in kinematic gait parameters of individual foals could be detected. These results contribute to an objective comparison of the locomotor performance of foals.
Stapley ED, Stutzman BE, Manfredi JM.The stirrup iron has the potential to modify the forces experienced by a horse and rider during ridden exercise. A range of stirrup designs are available, but no previous studies have investigated if these modifications influence riders' position and interaction with the horse. Novel flexible (F) or flexible and rotatable (FR) irons versus traditional (T) stirrups may positively impact the welfare and performance of the horse and rider. Four riders rode using the three stirrup types (T, F, and FR). Hip, knee, and ankle angles and toe position from film, and the normal force exerted bilaterally...
Smith JM, Meyers KM, Barbee DD, Schott H, Bayly WM.To determine whether plasma von Willebrand factor (vWf) concentration changes in horses during and after treadmill exercise. Methods: 5 mature, fit Thoroughbreds. Methods: A blood sampling catheter was placed in the right jugular vein. A warm-up period was followed by a 3-minute rest period. Horses were galloped at racing pace until fatigued (about 2 minutes). Blood samples were collected prior to warm-up, during the postwarm-up rest period, 1 minute into the run, at cessation of the run, and 5 to 120 minutes after cessation of the run. vWf activity was measured by ELISA and corrected for plas...
Borgia LA, Valberg SJ, McCue ME, Pagan JD, Roe CR.To evaluate effects of fats with odd and even numbers of carbon atoms on muscle metabolism in exercising horses with polysaccharide storage myopathy (PSSM). Methods: 8 horses with PSSM (6 females and 2 males; mean +/- SD age, 6.3 +/- 3.9 years). Methods: Isocaloric diets (grain, triheptanoin, corn oil, and high-fat, low-starch [HFLS] feed) were fed for 3 weeks each; horses performed daily treadmill exercise. Grain was fed to establish an exercise target, and HFLS feed was fed as a negative control diet. Daily plasma samples were obtained. For each diet, a 15-minute exercise test was performed,...
McDonough P, Kindig CA, Hildreth TS, Behnke BJ, Erickson HH, Poole DC.Maximal cardiac performance is improved in man during upright compared to supine exercise. Whether cardiac performance in quadrupeds is dependent upon body position is unknown. Therefore, we undertook the present investigation to determine if peak cardiac output (Qpeak) would be influenced by body inclination in the Thoroughbred horse. To test the hypothesis, four Thoroughbred horses performed an incremental exercise protocol (speed increased by 1 m/s/min to fatigue) on both a level (L) and inclined (I: 6 degrees) treadmill. Specifically, we hypothesised that Qpeak would be increased on the in...
