Exercise physiology in horses involves the study of the physiological responses and adaptations of horses to physical activity. This field examines how exercise impacts various systems in the equine body, including the cardiovascular, respiratory, muscular, and metabolic systems. Researchers focus on understanding how these systems interact during different types and intensities of exercise, and how they contribute to performance and recovery. Key areas of interest include the assessment of aerobic and anaerobic capacity, muscle fiber composition, energy metabolism, and thermoregulation. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms of exercise physiology in horses, with an emphasis on performance optimization, training regimens, and the prevention of exercise-related disorders.
McGuigan MP, Wilson AM.A horse's legs are compressed during the stance phase, storing and then returning elastic strain energy in spring-like muscle-tendon units. The arrangement of the muscle-tendon units around the lever-like joints means that as the leg shortens the muscle-tendon units are stretched. The forelimb anatomy means that the leg can be conceptually divided into two springs: the proximal spring, from the scapula to the elbow, and the distal spring, from the elbow to the foot. In this paper we report the results of a series of experiments testing the hypothesis that there is minimal scope for muscle cont...
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...
McKeever KH.Surveys indicate that up to 15% of the equine population in the United States is older than 20 years of age, with many of these animals performing various athletic activities well into their 20s. As is the case with their human counterparts, these geriatric equine athletes have the ability to continue to perform in athletic events. Unfortunately, many horse owners continue to train their active older animals using exercise training protocols that, although appropriate for a younger animal, may not be appropriate for the older equine athlete. Studies in aged human beings have led to a fine-tuni...
Ainsworth DM, Appleton JA, Eicker SW, Luce R, Julia Flaminio M, Antczak DF.The effect of strenuous exercise on the mRNA concentrations of interleukin-12p35 subunit (IL-12p35), interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) in equine pulmonary and peripheral blood mononuclear cells (PBMCs) was investigated. We hypothesized that strenuous exercise would suppress the expression of IL-12p35, IFN-gamma and augment the expression of IL-4. Eleven horses were randomly divided into two groups, a stall-confined control group (n=5) and an exercise-conditioned treatment group (n=6). Bronchoalveolar and PBMCs were obtained from horses in the treatment group prior to the co...
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 ...
Cable CS, Ducharme NG, Hackett RP, Erb HN, Mitchell LM, Soderholm LV.To investigate whether upper airway sounds of horses exercising with laryngeal hemiplegia and alar fold paralysis have distinct sound characteristics, compared with unaffected horses. Methods: 6 mature horses. Methods: Upper airway sounds were recorded in horses exercising on a high-speed treadmill at maximum heart rate (HR(MAX)) under 3 treatment conditions (ie, normal upper airway function [control condition], and after induction of left laryngeal hemiplegia or bilateral alar fold paralysis) in a randomized crossover design. Fundamental frequency, spectrograms using Gabor transform, and inte...
Smith RK, Birch HL, Goodman S, Heinegård D, Goodship AE.Strain-induced tendinopathy is a common injury in both human and equine athletes, with increasing incidence associated with greater involvement in sport and an increasingly aged population. This paper reviews our studies on the abundant non-collagenous protein, cartilage oligomeric matrix protein (COMP), in equine tendons. Its variation between tendon type and site, age and exercise has provided an insight into how age and exercise influence tendon growth and maturation. Tendons can be broadly divided into two types, reflecting their different matrix composition and function: the energy-storin...
Kearns CF, McKeever KH.The purpose of this 8-wk study was to examine the effect of therapeutic levels of clenbuterol on aerobic performance and hemodynamics associated with exercise. Methods: Twenty-three unfit Standardbred mares were divided into four experimental groups, clenbuterol (2.4 microg x kg(-1) body weight twice daily) plus exercise (20 min at 50% O2max; CLENEX; N = 6), clenbuterol only (CLEN; N = 6), exercise only (EX; N = 5), and control (CON; N = 6). All horses performed an incremental exercise test (GXT) to measure maximal oxygen consumption (O2max), blood lactate concentration, total plasma protein c...
Kirschvink N, Fiévez L, Bougnet V, Art T, Degand G, Smith N, Marlin D, Roberts C, Harris P, Lekeux P.An oxidant/antioxidant imbalance in favour of oxidants has been identified as playing a decisive role in the pathogenesis of chronic inflammatory airway diseases. Nutritional antioxidant supplementation might reduce oxidative damage by enhancement of the antioxidant defence, thereby modulating inflammatory processes. In a placebo-controlled, blind study, it was tested whether a dietary antioxidant supplement administered for 4 weeks would improve lung function and reduce airway inflammation in heaves-affected horses. Eight horses in clinical remission of heaves were investigated at rest and af...
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...
van de Lest CH, Brama PA, van Weeren PR.This study aimed at the determination of the influence of exercise on the levels of a number of bone morphogenic enzymes in subchondral bone and at the comparison of these data with other (subchondral) bone-related parameters that have been investigated in the same experimental population.Forty-three foals were reared until weaning at 5 months of age under similar conditions, except for the type and amount of exercise. Fifteen foals remained at pasture (Pasture group and also control group), 14 foals were kept in box stalls (Box group) and 14 foals were kept in the same box stalls but were sub...
van Loon G, Fonteyne W, Rottiers H, Tavernier R, Deprez P.A five-year-old gelding suffered syncope at the end of a period of exercise. A 24-hour electrocardiogram recording revealed intermittent pauses in the sinus rhythm of up to 10 seconds, indicating sinus node disease; the pauses occurred repeatedly, particularly after exercise. A dual-chamber, rate-adaptive pacemaker was successfully implanted, which prevented excessive postexercise bradycardia and syncope, and allowed the horse to return to work.
Vervuert I, Coenen M, Wedemeyer U, Harmeyer J.Seven untrained Standardbred horses were used in a training programme of 6 weeks to evaluate the effects of exercise and training on bone metabolism. The horses were exercised on a treadmill according to a standardized exercise test (SET 1: six incremental steps, 5 min duration each; start 5 m/s, increase 1 m/s). SET 1 was followed by a training programme of 6 weeks. In alternating order: high-speed exercise (HSE): 15 min duration, start at VLa4, continuous increase in speed every 60 s by 0.3 m/s (14 incremental steps); low-speed exercise (LSE): constant velocity at VLa2.5, duration: approxima...
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...
Ohmura H, Hiraga A, Aida H, Kuwahara M, Tsubone H.To determine the effects of initial handling and training on autonomic nervous functions in young Thoroughbreds. Methods: 63 healthy Thoroughbreds. Methods: All horses were trained to be handled and initially ridden in September of the yearling year and then trained until the following April by conventional training regimens. To obtain the heart rate (HR), electrocardiograms were recorded in the stable before initial handling and training and following 7 months of training; variations in HR were then evaluated from the power spectrum in terms of the low frequency (LF; 0.01 to 0.07 Hz) power an...
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...
St Lawrence AC, Lawrence LM, Coleman RJ.Many studies have examined the effect of pre-exercise feeding on glucose and insulin responses of horses. The objective of this study was to determine whether exercise performed one hour prior to a meal would attenuate the glucose and insulin responses to a meal. Data collected from 8 mature geldings in a 2 period crossover design experiment were used to determine the postprandial glucose and insulin responses to a meal of oats offered 1 h postexercise. During each period, 4 horses received a test meal following a 14 h fast (NoEx) or a 14 h fast and exercise bout (PostEx) that consisted of 48 ...
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...
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...
Karlström K, Essén-Gustavsson B.An assumed link between red cell hypervolaemia, an excessive amount of training and impaired performance of hypervolaemic horses has led to a theory that the muscle fibres could be affected. Myosin heavy chain (MHC)-based fibre type composition in gluteus medius muscle of red blood cell normo- (NV) and hypervolaemic (HV) Standardbred trotters was evaluated using immunohistochemistry. Muscle biopsies were obtained from 13 NV and 16 HV horses. Serial transverse sections were cut and reacted with antibodies against different isoforms of the myosin heavy chains MHCI, MHCIIA and MHCIIX. Sections we...
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...
Durando MM, Reef VB, Birks EK.Thorough evaluation of myocardial function remains difficult to evaluate under exercising conditions. This study described right ventricular (RV) pressure dynamics during and immediately following exercise. Nine Thoroughbreds without evidence of cardiac disease completed treadmill exercise at 110% of the speed necessary to elicit VO2max while RV pressures were recorded. RV pressure dynamics were calculated at rest, maximal speed and at 10 s intervals for 2 min after exercise. Stress echocardiography was performed at rest and within 120 s after exercise. Mean dP/dtmax and dP/dtmin values were s...
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...
Davie AJ, Priddle TL, Evans DL.This study was undertaken to invesigate the application of submaximal field tests in assessment of performance. A submaximal field exercise test consisting of 2 bouts of pacing for 1600 m, with 5 min rest or walking between runs was performed on Standardbred racehorses at 2 training centres (A and B). Performance indices were compiled for each horse: number of race starts, number of race wins, number of race placings (1, 2 or 3), and lifetime earnings. Regression analysis was conducted to describe the relationship between plasma lactate concentrations and speed for tests one, 2 and pooled resu...
Hyyppä S, Höyhtyä M, Nevalainen M, Pösö AR.Iron is of key importance for aerobic metabolism, and natural feeds of the horse are fairly rich sources of iron. Accordingly, the known incidence of iron deficiency anaemia is apparently rare in performance horses; despite this, iron deficiency in performance horses continues to be of concern to trainers and veterinarians. Effects of exercise on plasma ferritin concentrations were therefore studied in Standardbreds, Finnhorses and half-bred riding horses. Blood samples were taken after a moderate exercise test on a racetrack, a competition exercise test on a treadmill and a race. Even moderat...
Piccione G, Assenza A, Borruso M, Fazio F, Caola G.In the sport field, non-esterified fatty acids (NEFA) are important for the physical performance during the aerobic exercise of short intensity and long duration. In man, rat, goat and in the sedentary horse studies on the chronometabolism showed the presence of a circadian rhythm of the plasmatic concentration of NEFA while data for the athletic horse are lacking. To define a chronogram helpful for a specific planning and the differentiation of the training programmme in the athletic horse, the circadian pattern of some fatty acids (NEFA, palmitic, stearic, oleic, linoleic and linolenic acids...
Hobbs SJ, Clayton HM.One of the goals of the neuromotor control system is to minimize the cost of locomotion by reducing mechanical energy losses. Collisional mechanics, which studies the redirection of the downwards motion of the center of mass (COM) by ground reaction forces (GRF) generated by the limbs, represents an important source of energy loss. The primary objective of this study was to compare collisional mechanics and the associated mechanical energy losses in horses performing diagonally-synchronized gaits over a range of speeds. It is to be expected that collisional energy losses will be high when the ...
Thevis M, Opfermann G, Krug O, Schänzer W.Isotope-dilution mass spectrometry has been employed successfully in numerous fields of analytical chemistry enabling the establishment of fast and reliable procedures. In equine sports, xanthine derivatives such as caffeine and theobromine are prohibited, and doping control laboratories analyze horse urine specimens regarding these illicit performance-enhancing drugs. Theobromine has to exceed a threshold level of 2 microg/mL, hence a robust and reliable quantitation is required. Stably deuterated theobromine and caffeine were synthesized by the reaction of xanthine or theobromine with iodome...
Marichal G, Trigo P, Soto C, Meikle A, Suárez G.The Raid Uruguayo (RAID) is an equestrian endurance competition. This study characterized the hydroelectrolytic parameters (Na, K, Cl, tCa, and iCa), hematocrit (Ht), total plasma protein (TPP), and blood pH from 900 equine athletes (finishers and non-finishers) competing over distances of 80 to 115 km under different climate conditions. Paired blood samples were taken prior to the start of the competition (sample 1) and at the end of the race or at the time of leaving the competition (sample 2). The association of the comfort index (CI: low, moderate, and high) with blood parameters was evalu...
Lindner A, Esser M, López R, Boffi F.In endurance racing the heart rate (HR) of horses in the veterinary gates has to reach a maximum set to continue racing. There is no literature on the relationship between resting HR (HRresting) and HR after exercise (HRrecovery). This relationship was examined in seven horses and the results were related to their v (speed at which the blood lactate concentration is 4 mmol/L). Horses were submitted to an exercise test to determine v. Thereafter, horses were exercised on a treadmill in randomized order for 10 and 60 min at different speeds. HR was measured before exercise and several times unti...
Nath LC, Forbes G, Elliott AD, Tomren V, Ryan A, Franklin SH.AliveCor is a smartphone electrocardiography device (iECG) providing automated heart rate (HR) and rhythm determination. Atrial fibrillation (AF) in horses often is paroxysmal and rapid ECG acquisition is needed for diagnostic confirmation. iECGs were collected post-race from 15 horses with AF and 64 horses in sinus rhythm (SR). Results of manual assessment were compared to 3 commercial algorithms for HR and rhythm. Agreement between manually derived HR (HRM ) and HR derived by the AliveECG Vet (HRVET ) and Kardia version-1 (KV1 HR) and Kardia advanced (KADV HR) algorithms was quantified by th...
Elgersma AE, Wijnberg ID, Sleutjens J, van der Kolk JH, van Weeren PR, Back W.Head and neck positions (HNP) in sport horses are under debate in the equine community, as they could interfere with equine welfare. HNPs have not been quantified objectively and no information is available on their head and neck loading. Objective: To quantify in vivo HNPs in sport horses and develop o a model to estimate loading on the cervical vertebrae in these positions. Methods: Videos were taken of 7 Warmbloods at walk on a straight line in 5 positions, representing all HNPs during Warmblood training and competition. Markers were glued at 5 anatomical landmarks. Two-dimensional angles a...
Nam GH, Ahn K, Bae JH, Cho BW, Park KD, Lee HK, Yang YM, Kim TH, Seong HH, Han K, Kim HS.In the mitochondrial matrix, the OXCT1 gene catalyzes the reversible transfer of coenzyme A from succinyl-CoA to acetoacetate in a reaction related to energy production from ketone bodies. Here, horse OXCT1 gene containing coenzyme A transferase domain was identified in the transcriptome analysis of cDNAs derived from skeletal muscles. Horse OXCT1 gene consisted of 1761 [corrected] nucleotide sequences with an open reading frame of 1560 nucleotides encoding a protein of 520 putative amino acid residues.The number of non-synonymous substitutions was lower than the number of synonymous substitut...
Boucher JH, Ferguson EW, Wilhelmsen CL, Statham N, McMeekin RR.The erythrocytes of 14 conditioned horses participating in a 157-km endurance ride (requiring 14-21 h) were examined before the ride, immediately upon entering the 44-91-, and 130-km rest stops, and at the finish. At the first rest stop (44 km), the mean erythrocyte count increased 41% (P less than 0.001), the mean hematocrit (Hct) increased 30% (P less than 0.001) and the mean hemoglobin (Hb) increased 33% ( P less than 0.001). Although subsequent mean erythrocyte counts, Hct, and Hb values remained significantly elevated above controls, the values decreased 9-9% from the 4-km values later in...
Jones S, Franklin S, Martin C, Steel C.There is limited knowledge of the breathing strategy and impact on the patency of the upper respiratory tract (URT) in swimming horses. Objective: To describe the respiratory responses and endoscopic appearance of the URT during tethered swimming in horses. Methods: Prospective descriptive study. Methods: Ten race-fit horses, with no history of URT obstruction, were examined during tethered swimming. Endoscopic examination, heart rate, sound recordings and above and below water video recordings were obtained. Plasma lactate concentration was measured before and 5 min after swimming and trache...
Sloet van Oldruitenborgh-Oosterbaan MM, Wensing T, Barneveld A, Breukink HJ.To determine whether a clinical examination was adequate to assess the fitness of horses in an endurance ride, and to characterise the relationship between a clinical assessment of the horse's fitness and its blood biochemistry, 23 horses were monitored before, during and after an 87 to 100 km endurance ride. Blood samples were taken before the ride, at three checkpoints on the ride, immediately after the ride and one day later for the determination of packed cell volume, total protein, lactate, glucose, non-esterified fatty acids, creatine phosphokinase, aspartate aminotransferase and plasma ...
Smarsh DN, Liburt N, Streltsova J, McKeever K, Williams CA.Many nutraceuticals are used as equine supplements without their efficacy having been scientifically tested. Black tea, cranberries, orange peel and ginger are a few of those nutraceuticals that warrant further study. Objective: To test the effects of single doses of black tea, cranberry, orange peel and ginger extract on markers of oxidative stress and antioxidant status following exercise in horses. Methods: In Study 1, 9 mature, healthy but unfit Standardbred mares were administered 2 l of a control (water), orange peel extract (30 g extract) or decaffeinated black tea extract (28 g extract...
Walmsley EA, Steel CM, Richardson JL, Hesse KL, Whitton RC.To describe the clinical presentation, ultrasound findings, management and outcome in horses with muscle tear injuries of the hindlimbs. Methods: Retrospective case series Procedure Medical records of eight horses were reviewed and information on signalment, history, presenting complaint, physical examination findings and further diagnostic tests were recorded. Diagnosis of muscle injury was determined by the presence of abnormal ultrasound findings, compared with the contralateral limb, and, when required, nuclear scintigraphy. Follow-up information was obtained via telephone interviews with ...
Salbaş E, Karahan AY.Newly created systems called hippotherapy simulators (HS) mimic the primitive movements of a live horse. As they are new systems, research examining their usefulness has been well received. The aim of this study is to research the effects of HS on disease activity, quality of life and muscle strength in patients with ankylosing spondylitis (AS). Unassigned: In a prospective, assessor-blinded, block-randomized trial, 48 AS patients were randomly assigned in a 1:1 ratio to receive either HS or conventional home (CH) exercise therapy. All Participants received 48 sessions, that is 4 sessions a we...
Fenger CK, McKeever KH, Hinchcliff KW, Kohn CW.To determine components of the increase in oxygen consumption (VO2) and evaluate determinants of hemoglobin saturation (SO2) during incremental treadmill exercise in unfit horses. Methods: 7 unfit adult mares. Methods: Horses performed 1 preliminary exercise test (EXT) and 2 experimental EXT. Arterial and mixed venous blood samples and hemodynamic measurements were taken during the last 30 seconds of each step of the GXT to measure PO2, hemoglobin concentration ([Hb]), SO2, and determinants of acid-base state (protein, electrolytes, and PCO2). Results: Increased VO2 during exercise was facilit...
Essén-Gustavsson B, Jensen-Waern M.Glycogenolysis and lipolysis are essential for energy production in muscle during prolonged exercise but less is known about the role of amino acid metabolism. The aim was to study the effect of an endurance race on pro- and macroglycogen, triglycerides and amino acid concentrations in muscle and on selected blood parameters, especially the amino acid response in the blood during the recovery phase. Seven endurance-trained horses completed a race covering 100-120 km. Blood samples were collected one day before the race, after the finish and 1 and 8 days after the race. Needle biopsy specimens ...
Ramón T, Prades M, Armengou L, Lanovaz JL, Mullineaux DR, Clayton HM.Athletic taping is used frequently by human athletes to stabilise, maintain or strengthen soft tissue structures, but empirical evidence supporting any changes in equine kinematics is lacking. Objective: To assess the effects of athletic taping of the fetlock applied by an experienced athletic trainer on forelimb mechanics in healthy horses. Objective: That athletic taping of the distal forelimb reduces 1) hyperextension of the fetlock joint during stance, 2) flexion of the fetlock joint during swing and 3) ground reaction forces during stance. Methods: Ground reaction force and kinematic data...
Sosa León LA, Hodgson DR, Rose RJ.We examined the gastric emptying (GE) of oral rehydration solutions (ORS) at rest and after exercise in four Standardbred horses. In one study isotonic, cold isotonic (5 degrees C), isotonic containing glucose and hypertonic fluid were tested at rest. In another study, isotonic fluid was given following a bout of treadmill exercise at 70 per cent VO2 max until exhaustion or at rest. In both studies, a single dose of 8 litres was given via nasogastric tube. GE and electrolyte concentrations (Na+, K+ and Cl-) of the stomach content were measured at 15 minutes intervals for one hour. In both stud...
Portier K, de Moffarts B, Fellman N, Kirschvink N, Motta C, Letellierw C, Ruelland A, van Erck E, Lekeux P, Couder J.Fatty acid supplementation could modulate erythrocyte membrane fluidity in horses at rest and during exercise, but information is lacking on the effect of exercise. Objective: To assess the effect of exercise with, and without, an oral antioxidant supplementation enriched with n-3 fatty acids on erythrocyte membrane fluidity (EMF) and fatty acid composition in eventing horses. Methods: Twelve healthy and regularly trained horses were divided randomly into 2 groups: group S received an oral antioxidant cocktail enriched in n-3 fatty acid (alphatocopherol, eicosapentaenoic acid [EPA] and docosah...
Takahashi T, Matsui A, Mukai K, Ohmura H, Hiraga A, Aida H.It is important to know the effects of the inclination of a slope on the activity of each muscle, because training by running on a sloped track is commonly used for Thoroughbred racehorses. The effects of incline (from -6 to +6%) on the forelimbs and hind limbs during walking and trotting on a treadmill were evaluated by an integrated electromyogram (iEMG). The muscle activities in the forelimbs (5 horses) and hind limbs (4 horses) were measured separately. Two stainless steel wires were inserted into each of the brachiocephalicus (Bc), biceps brachii (BB), splenius (Sp), and pectoralis descen...
Davis MS, Lockard AJ, Marlin DJ, Freed AN.In human subjects that exercise strenuously in cold weather, there is evidence that hyperventilation with cold air leads to peripheral airway cooling, desiccation and mucosal injury. Our hypothesis was that hyperventilation with cold air can result in penetration of unconditioned air (air that is not completely warmed and humidified) into the peripheral airways of exercising horses, resulting in peripheral airway mucosal injury. To test this hypothesis, a thermister-tipped catheter was inserted through the midcervical trachea and advanced into a sublobar bronchus in three horses that cantered ...
Vervuert I, Coenen M, Wedemeyer U, Harmeyer J.Seven untrained Standardbred horses were used in a training programme of 6 weeks to evaluate the effects of exercise and training on bone metabolism. The horses were exercised on a treadmill according to a standardized exercise test (SET 1: six incremental steps, 5 min duration each; start 5 m/s, increase 1 m/s). SET 1 was followed by a training programme of 6 weeks. In alternating order: high-speed exercise (HSE): 15 min duration, start at VLa4, continuous increase in speed every 60 s by 0.3 m/s (14 incremental steps); low-speed exercise (LSE): constant velocity at VLa2.5, duration: approxima...
Shappell KK, Derksen FJ, Stick JA, Robinson NE.Effects of ventriculectomy and prosthetic laryngoplasty on upper airway flow mechanics and blood gas tensions in exercising horses with induced left laryngeal hemiplegia were assessed. Five adult horses were trained to stand, trot (4.5 m/s), and gallop (7.2 m/s) on a treadmill (6.38 degrees incline). Inspiratory and expiratory airflows (VImax, VEmax, respectively) were measured using a 15.2-cm diameter pneumotachograph in a face mask. Inspiratory and expiratory transupper airway pressures (PuI, PuE, respectively) were determined as pressure differences between barometric pressure and lateral t...
Bayly WM, Schultz DA, Hodgson DR, Gollnick PD.Experiments were undertaken to determine whether respiratory masks worn by horses exercising strenuously on a treadmill may interfere with normal gas exchange. Four collection systems, two flow-through systems and two incorporating one-way valve systems with subject-generated airflow were studied. Six horses performed standard treadmill exercise tests consisting of a 2-min warm up followed by galloping 1 min each at 8,9, and 10 m/s. Each horse exercised six times while wearing each of the four respiratory masks. Each flow-through system was used twice with flow rates of 2,360 and 3,840 l/min f...
Gonzalez ML, Jacobs RD, Ely KM, Johnson SE.Postexercise skeletal muscle repair is dependent on the actions of satellite cells (SCs). The signal(s) responsible for activation of these normally quiescent cells in the horse remain unknown. The objective of the experiment was to determine whether submaximal exercise or tributyrin (TB) supplementation is sufficient to stimulate SC activation. Adult geldings were fed a control diet (n = 6) or a diet containing 0.45% TB (n = 6). After 30 d, the geldings performed a single bout of submaximal exercise. Middle gluteal muscle biopsies and blood were collected on days -1, 1, 3, and 5 relative to e...
Khumsap S, Clayton HM, Lanovaz JL.To measure the effect of subject velocity on hind limb ground reaction force variables at the walk and to use the data to predict the force variables at different walking velocities in horses. Methods: 5 clinically normal horses. Methods: Kinematic and force data were collected simultaneously. Each horse was led over a force plate at a range of walking velocities. Stance duration and force data were recorded for the right hind limb. To avoid the effect of horse size on the outcome variables, the 8 force variables were standardized to body mass and height at the shoulders. Velocity was standard...
Graham-Thiers PM, Bowen LK.Feeding management in horses suggests feeding horses in advance of exercise, particularly the grain portion of the diet. Plasma amino acids () peak at 3 to 6 h postfeeding depending on the AA. The timeframe between feeding and exercise may affect the availability of AA during and after exercise. The purpose of this study was to observe the differences in plasma AA in horses fed prior to exercise or after exercise. Eight light type horses were fed a diet with adequate protein and AA for horses in light to moderate exercise. After an adjustment period, horses completed a standardized exercise te...
Geser-von Peinen K, Latif SN, Wiestner T, Bitschnau C, Renk B, Weishaupt MA.With the intention of limiting the weight on horses' backs and guaranteeing maximal freedom of movement, commonly used racing saddles are small and have minimal cushioning. Poor saddle cushioning may limit performance or even affect soundness of the back. The aim of this study was to measure the pressure under an average racing saddle ridden by a jockey at racing speed. Saddle pressure using a medium-sized racing saddle (length 37 cm, weight 450 g) was measured in five actively racing Thoroughbred horses. All horses were trained at the same facility and ridden by their usual professional jocke...
Waller A, Lindinger MI.In human and animal clinical practice, multi-frequency bioelectrical impedance analysis (MF-BIA) is increasingly used as a diagnostic tool to assess hydration of intra-and extracellular fluid compartments. Accurate determination of changes in hydration status within individuals over time has remained problematic due to the requirement for complete impedance-frequency relationships at the time points of interest. Objective: To use MF-BIA in 13 Standardbred racehorses and 7 'endurance' research horses to determine if MF-BIA could be used to track changes in total body water (TBW), intracellular ...
Santamaría S, Bobbert ME, Back W, Barneveld A, van Weeren PR.To quantify variation in the jumping technique within and among young horses with little jumping experience, establish relationships between kinetic and kinematic variables, and identify a limited set of variables characteristic for detecting differences in jumping performance among horses. Methods: Fifteen 4-year-old Dutch Warmblood horses. Methods: The horses were raised under standardized conditions and trained in accordance with a fixed protocol for a short period. Subsequently, horses were analyzed kinematically during free jumping over a fence with a height of 1.05 m. Results: Within-hor...
