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.
van den Broek M, Chan ZYS, De Bruyne C, Garcia-Alamo K, Skotarek Loch S, Pfau T.Increased risk of musculoskeletal injury in galloping racehorses has been linked to decreased stride length and reduced speed over consecutive races prior to the injury. As racetrack curvature influences horses' maximal speed, we hypothesized it also affects stride parameters. During training sessions, twenty-eight wagon-pulling Thoroughbred Chuckwagon horses were equipped with Global Navigation Satellite System (GNSS) loggers, allowing for identification of speed, stride length (SL) and stride frequency (SF), and average speed, SL and SF were calculated for consecutive 100 m sections. Effects...
Bao Y, Wang T, Adina W, Yao R, Chu H, Yao X, Meng J, Wang J, Ren W, Zeng Y.This study aimed to investigate how different training outcomes affect the gut microbiota composition in racehorses. Twenty-six Yili horses underwent a 9-month conditioning training regimen under uniform husbandry and management conditions. Post-training, the horses were divided into an excellence group (D. Y group) and a general group (D. P group) based on their athletic performance, with the top 10 performers constituting the D. Y group and the bottom 10 the D. P group. Cardiac morphology and function were quantitatively assessed via echocardiography, and metagenomic sequencing was performed...
Brito G, Damián JP, Trigo P, Ruprechter G.The Raid Hípico Uruguayo (RHU) is the oldest equestrian endurance sport in Uruguay. A high percentage of horses fail to complete RHU rides. Therefore, the aim of this study was to investigate whether weather conditions (comfort index [CI]), horse experience, and ride distance affect horse performance (finishing ride [FR] or nonfinishing ride [NFR]) in the RHU. An additional objective was to determine whether finishing the ride affects the hematological and biochemical parameters of the horses. This study involved 17 RHU rides over distances of 60-90 km and 284 horses. Blood samples were tak...
Littiere TO, da Costa GB, de Sales NAA, de Carvalho JRG, Rodriguez IDM, Ramos GV, de Lacerda-Neto JC, Ferraz GC.Maximal lactate steady state (MLSS) and its predictive thresholds, including the lactate threshold (LT), are widely used to estimate endurance capacity, prescribe training, and assess the effects of training. The human literature identified approximately twenty-five methods to predict the MLSS. This communication compares the concordance between the two D methods and the MLSS. Under laboratory conditions, ten teaching horses underwent a submaximal graded exercise test (GXT) on a treadmill to obtain their lactate-velocity curves (LVC). They performed three to five 30-min continuous running sess...
Wang T, Li M, Ren W, Meng J, Yao X, Chu H, Yao R, Zhai M, Zeng Y.Yili horses undergo coordinated physiological adaptations across systems in response to customized training. This study aimed to clarify the molecular mechanisms of these adaptations by integrating analyses of cardiac function and multi-omics (lipidomics, transcriptomics, miRNomics). We collected whole blood samples from ten Yili horses before and after 12 weeks of specialized racing training to perform these analyses. Results showed training induced adaptive cardiac remodeling, with substantial increases in LVIDd and LVIDs. At the molecular level, this was accompanied by extensive blood lipid...
Zuluaga-Cabrera AM, Barbosa da Costa G, Martinez ID, Arias MP.Colombian Paso horses (CPs) excel in gait competitions due to their endurance, speed, and precision, which demand a high level of cardiorespiratory fitness. However, their training regimes often lack scientific support, and few studies have linked physiological parameters to optimal training zones. This study aimed to estimate the aerobic lactate threshold (LTaer) using mathematical methods and to correlate it with heart rate (HR) zones and blood lactate. Eighteen CPs were evaluated and classified into trained (GT) and untrained (GD) groups. All animals underwent a field-based incremental exer...
Giannone C, Atallah E, Dalla Costa E, Benetti E, Santolini E, Tassinari P, Bovo M.Technology for monitoring behaviour and health of horses has evolved significantly, presenting new opportunities and challenges in equine management and healthcare. This scoping review consolidates recent findings on wearable sensors and non-contact technologies, discussing their benefits and limitations. Among these advancements, heart rate monitors stand out as a key point in equine monitoring. By tracking heart rate variability, devices help monitor cardiac autonomic regulation, optimise training regimens and allow early detection of cardiac issues, although accuracy can be compromised by i...
Wang T, Huang J, Ren W, Meng J, Yao X, Chu H, Yao R, Zhai M, Zeng Y.This study aimed to investigate the regulatory mechanisms underlying the relationship between cardiac structure and function and plasma metabolic characteristics in Yili horses participating in an 80-km endurance, by integrating echocardiography, lipidomics, and energy metabolomics analyses. Twenty four competing Yili horses were selected and divided based on competition outcomes: Pre-Completion Group: PCG ( = 6); Post-Completion Group: PoCG ( = 6); Overtime Completion Group: OCG ( = 6); and Non-Completion Group: NCG ( = 6). Cardiac structural and functional parameters were assessed via echoca...
Wang T, Yang X, Ren W, Meng J, Yao X, Chu H, Yao R, Zhai M, Zeng Y.Exercise performance is a critical trait for evaluating the economic and breeding value of working and athletic horses, with cardiac structure and function serving as essential physiological determinants of athletic capacity. This study aimed to investigate the multi-omics response mechanisms associated with varying degrees of cardiac remodeling under identical exercise intensity. Twenty 2-year-old Yili horses were selected and categorized based on echocardiographic parameters into a high cardiac remodeling group (BH; EDV > 500 mL, SV > 350 mL, EF > 66%) and a low cardiac remodeling group (BL;...
Aarts RM, Smit IH, Ferraz GC, Rhodin M, Serra Braganca FM, Hernlund E.Assessment of equine metabolic and locomotory responses to quantified levels of physical exercise is needed to support the creation of tailored protocols for optimal training adaptation. The locomotory response to exercise in horses is not fully understood. Objective: To investigate the effect of a standardised exercise test (SET) on upper-body and limb kinematics and stride-to-stride variability in Standardbred Warmblood trotters. Methods: Experimental repeated-measures field study. Methods: Thirteen Standardbred trotters, equipped with nine inertial measurement units (IMUs), performed an inc...
Mainguy-Seers S, Grondin SM, Lavoie JP.Airway dysfunction in severe equine asthma (SEA) often results in early retirement or euthanasia of affected horses. Exercise-induced bronchodilation occurs in horses with SEA after intense treadmill exercise, but the effects of a lighter, field-applicable, training regimen remain largely unexplored. Objective: To evaluate the impact of submaximal aerobic exercise on airway obstruction during exacerbation of SEA. Methods: The preliminary phase explored the effects of a 25-min standardised exercise on the lung function of eight SEA horses. As notable bronchodilation occurred, the results were c...
Rump-Dierig I, Giers J, Frenzel C, Stöckle S, Gehlen H.This study examines seasonal changes in muscle and heart parameters in eventing horses over the course of a competition season. Blood levels of the enzymes creatine kinase (CK) and aspartate aminotransferase (AST) as well as the heart muscle-specific concentration of cardiac troponin I (cTnI) were measured before (pre), 30 min (p30) and 24 h (p24) after competitions. Creatine kinase (CK: median pre-competition = 175 U/L, 30 min post = 221 U/L, 24 h post = 140 U/L), aspartate aminotransferase (AST: pre = 319 U/L, p30 = 335 U/L, p24 = 333 U/L), and cardiac troponin I concentration (cTnI: pre = 0...
St George L, Nankervis K, Walker V, Maddock C, Robinson A, Sinclair J, Hobbs SJ.Despite growing evidence on the adaptive movement patterns that horses adopt during water treadmill (WT) exercise, underlying adaptations in muscle activity remain uninvestigated. This feasibility study aimed to develop a method for the synchronous measurement of muscle activity and movement of horses during WT exercise. Combined surface electromyography (sEMG) (2000 Hz) from selected hindlimb (biceps femoris, gluteus medius, tensor fasciae latae) and epaxial (longissimus dorsi) muscles, and three-dimensional kinematic (200 Hz) data from the back and pelvis of one (n = 1) horse were collected ...
Wang T, Yang X, Ren W, Meng J, Yao X, Chu H, Yao R, Zhai M, Zeng Y.Training not only enhances the athletic performance of horses but also improves cardiac structure and function, strengthens cardiovascular adaptability, and reduces the risk of cardiovascular diseases. However, the consequences of training on equine cardiac structure and function remain unclear. This study investigated the morphological, functional, genetic, and metabolic changes in the hearts of Yili horses divided into three groups: high athletic performance (agility group, AG), low athletic performance (ordinary group, OG), and untrained (untrained group, UN). The results showed remodeling ...
Purnama MTE, Fikri F, Çalışkan H, Wicaksono AP.Racehorses endure high physical demands, which often result in musculoskeletal pain, fatigue, and reduced performance. Although conventional therapies are effective, competition-related drug regulations restrict their use. Acupuncture, rooted in Traditional Chinese Veterinary Medicine, has gained interest as a non-pharmacological alternative for managing pain, enhancing recovery, and promoting overall welfare in equine athletes. This review aims to critically evaluate the current evidence on the efficacy of acupuncture in racehorses, focusing on musculoskeletal pain management, post-exercise r...
Hammack SM, Moshage SG, Kersh ME, McCoy AM.To quantify circulating levels of myokines with a known role in bone remodeling (receptor activator of nuclear factor κ B ligand [RANK-L], matrix metalloproteinase 2 [MMP-2], and irisin) in foals in response to exercise and over the first year of life. Unassigned: 12 foals were enrolled in the study; 6 underwent an 8-week exercise program, and 6 were nonexercised controls. Blood samples were collected between 2 and 11 months of age. Receptor activator of nuclear factor κ B ligand, MMP-2, and irisin were quantified using equine-specific ELISAs. Unassigned: RANK-L, MMP-2, and irisin did not ch...
Sande A, Santosuosso E, Scharf JE, Shoemaker SJ, Temple S, Hemmerling K, Kell T, Leguillette R, Bayly WM.To compare maximal lactate steady-state (MLSS) speeds determined using a treadmill-dependent invasive reference method (RM) with 2 noninvasive methods based on heart rate variability-focused analysis of exercise ECGs. Unassigned: This was a randomized, blinded study using 7 fit Thoroughbreds. A standardized incremental exercise treadmill test (SET) where blood lactate concentration ([La]) was measured after every step facilitated calculation of speeds at which [La] was 1.5, 2.0, and 2.5 mmol/L. The RM required steady-state exercise (SS) at each of these speeds for 25 minutes or until [La] incr...
Training on deep sand is commonly employed in endurance horses, but its physiological adaptation remains poorly characterized. This study aimed to characterize locomotor adaptations during a 7 km controlled-speed canter on deep sand in eighteen endurance horses, to identify heart rate variability (HRV) components, and to investigate changes in hematological variables before and after exercise. Stride frequency (SF) and stride length (SL), HRV, and hematological profiles were recorded during exercise and recovery with a fitness tracker. Associations between maximum speed and locomotor parameter...
Jeong S, Bond S, Bayly W, Sole-Guitart A.To quantify the impact of experimentally induced dorsal nasopharyngeal collapse (NPC) on respiratory performance parameters and assess the efficacy of laser fenestration of the dorsal pharyngeal recess as a treatment option for experimentally induced NPC. Methods: Experimental interventional study. Methods: Six adult Standardbreds (one with naturally occurring disease). Methods: After an 8 week conditioning program, baseline parameters (V̇Omax, pharyngeal pressure, peak airflows, upper airway resistance) and dynamic endoscopy videos were collected in a high-speed treadmill test (T1). Dorsal N...
Park T, Hong S, Murray L, Lee J, Shah A, Mesa JC, Lee H, Couetil L, Lee CH.Continuous physiological monitoring is well-established in human healthcare for early disease detection and management. However, translation of these technologies to large animals such as equines remains underdeveloped due to anatomical constraints, dense hair coat coverage, and requirements for unimpeded mobility. Equines, particularly racehorses, are prone to asthma and cardiovascular abnormalities, with nearly 80 % affected by mild to moderate asthma, impacting performance and long-term health. Despite the need for continuous monitoring, existing solutions require shaving hairs, often lack...
Saitua A, Pérez-Umbría J, García-Álamo K, Muñoz A.Dynamic mobilization exercises (DME) are an effective strategy to prevent musculoskeletal injuries and promote back health in sport horses. Previous studies focused mainly on multifidus muscle cross-sectional area, with limited data on locomotion and adaptation timing. This study evaluated locomotor changes using accelerometry, over 8 weeks of DME application in 14 sedentary horses: a DME group ( = 8) performing 10 different DME (3 neck flexions, 1 neck extension and 3 lateral bending exercises to each side), 5 repetitions of each DME per session, 3 sessions/week, and a control group ( = 6), t...
Söderroos D, Stefánsdóttir GJ, Ragnarsson S, Gunnarsson V, Jansson A.Weight-carrying capacity is important in riding horses both for performance and welfare, yet there is no standardized method to estimate individual horses' weight-carrying capacity. This study investigated the correlation between the physiological response during a (i) standardized incremental exercise test (SET) on a treadmill and a (ii) ridden incremental weight-carrying exercise test (WET). Sixteen horses (15 ± 3 years) performed both tests, including four steps with increased speed or weight load, respectively. Body weight ratio (BWR) in the WET was 20%, 25%, 30%, and 35% in each st...
Huang Q, Ren W, Shan D, Su Y, Li Z, Li L, Wang R, Ma S, Wang J.This study aimed to compare blood samples from Yili horses with outstanding and average performance in 5000 m races through transcriptome sequencing, identify key differentially expressed genes, lncRNAs, and circRNAs, as well as related enriched pathways, and elucidate their regulatory networks. This study used six healthy four-year-old Yili stallions as subjects, divided into an excellent group (E group, = 3) and an ordinary group (O group, = 3) based on their 5000-m race performance. Blood RNA-Seq technology was used to analyze differentially expressed mRNAs, lncRNAs, and circRNAs. A total...
Frontiers in geneticsOctober 1, 2025
Volume 16 1676558 doi: 10.3389/fgene.2025.1676558
Ma S, Ren W, Li Z, Li L, Wang R, Su Y, Huang Q, Dehaxi S, Wang J.Equine athletic performance is modulated by both genetic and epigenetic mechanisms. As dynamic regulators of gene expression, MicroRNAs (miRNAs) play a central role in the physiological response to exercise-induced stress18. This study focused on the top three elite Yili horses from a 5000-m race, collecting peripheral blood samples pre-race (group B) and post-race (group A). A longitudinal comparative analysis integrating miRNA omics profiling and target gene functional enrichment was performed. Nineteen miRNAs exhibited significant differential expression (10 upregulated, 9 downregulated), w...
Kapusniak A, Lara NM, Hitchens PL, Bailey S, Nath L, Franklin S.Artificial intelligence (AI) is increasingly used to enhance electrocardiogram (ECG) interpretation in human medicine. In equine athletes, exercise-associated arrhythmias are common and linked to sudden cardiac death at rates higher than in humans. However, ECG interpretation in horses remains time-consuming and subjective, with the clinical relevance of mild rhythm disturbances often unclear. Objective: Evaluate the application of AI to ECG interpretation for arrhythmia detection, with emphasis on current and potential use in athletic species, particularly horses. Methods: About 17 studies we...
Allen TS, Johnson S.The physical stresses on equine athletes are unique and differ across various disciplines. Recognizing these differences is essential for early detection of injuries and effective management of the competition horse's health. Equine sports medicine involves specific challenges and risks that can be reduced through proper care, careful attention to technique, and a deep understanding of the demands of each sport. Proper training, regular monitoring, and sport-specific expertise are crucial in preventing injuries and ensuring optimal performance. By focusing on these aspects, veterinarians and t...
Ergin HK, Bekdik İK, van den Hoven R, Onmaz AC.Dimethylglycine (DMG) may help delay muscle fatigue and prevent exercise-induced muscle damage in athletic animals. This study investigated the effects of intravenous and oral DMG on physiological, hematological, biochemical, blood gas, and oxidative stress parameters in exercising horses. In this study, 30 Turkish Arab saddle horses were randomly divided into three groups. Group A horses were injected intravenously with 15 mL (1500 mg) of a 10 % DMG twice daily for three days. Group B horses received 1500 mg DMG powder orally twice daily for three days, and group C (control) horses we...
Avison A, Goderre BG, Pyle WG, Physick-Sheard PW.Sudden cardiac death is common in racehorses. Factors associated with the QT interval that could predispose to fatal cardiac arrhythmias are unknown. Cardiac restitution, expressed as a ratio of QT/TQ, has been used in humans to assess arrhythmia risk but has not been described in horses during maximal intensity exercise. Objective: Describe factors associated with the QT interval and cardiac restitution ratio (CRR) in clinically normal Standardbred racehorses under race-day conditions. Methods: Archival electrocardiograms from 42 Standardbred horses during live racing in Ontario. Methods: Obs...
Aarts RM, Siegers EW, Serra Braganca FM, van Weeren PR.The need for comprehensive equine welfare assessments has become particularly evident amid ongoing debates about the social licence to operate in equestrian sports. During exercise, multiple physiological systems, principally the cardiovascular, respiratory, muscular, thermoregulatory, endocrine, and locomotory systems, undergo complex adaptations. To monitor and determine equine welfare, an approach that focuses on the quantitative monitoring of both physiological and psychological parameters to determine and understand the impact of equestrian sports on horses is essential. Existing and emer...
Witkowska-Piłaszewicz O, Nowicka-Kazmierczak M, Pietrzak P, Marycz K.Skeletal muscle satellite cells ( SCs), essential for muscle regeneration, are a valuable model for studying exercise-induced stress relevant to human athletes. This study examined the effects of two natural compounds-chlorogenic acid (CGA) and isovanillic acid 3-O-sulfate (IVAS)-increasingly recognized as components of modern, nature-based recovery strategies. Their combination (Hybrid) was also tested on equine model of skeletal muscle satellite cells (ESCs) exposed to heat shock (40 °C, 1 h), mimicking exercise stress. Cells were treated with CGA (0.005%), IVAS (0.0005%), or both for 24...
Minetti AE.By refining a previously published model, a simple equation for the estimation of the mechanical internal work during locomotion is presented. The only input variables are the progression speed, the stride frequency and the duty factor, i.e. the fraction of the stride duration at which a foot is in contact with the ground. The inclusion of this last variable, easily measurable, allows to obtain a single equation for both walking and running. The model predictions have been compared with the mechanical internal work experimentally obtained on humans in several conditions: speeds (range 0.8-3.3 ...
Kirschvink N, de Moffarts B, Lekeux P.Since "free radical research" started in 1954, understanding the role of oxidants and antioxidants in physiological and pathological conditions has increased continuously. Oxidants are essentially generated by metabolic enzymes, inflammatory cells and mitochondrial electron leakage; they are indispensable for the cellular redox regulation and may, under certain conditions, have a pro-inflammatory stimulatory role. Endogenous and exogenous antioxidants counterbalance the oxidative processes and so maintain the oxidant/antioxidant equilibrium. Excessive oxidant generation or antioxidant insuffic...
Weishaupt MA, Wiestner T, Hogg HP, Jordan P, Auer JA.The study was performed to obtain a detailed insight into the load and time shifting mechanisms of horses with unilateral weight-bearing forelimb lameness. Reversible lameness was induced in 11 clinically sound horses by applying a solar pressure model. Three degrees of lameness (subtle, mild and moderate) were induced and compared with sound control measurements. Vertical ground reaction force-time histories of all four limbs were recorded simultaneously on an instrumented treadmill. Four compensatory mechanisms could be identified that served to reduce structural stress, i.e. peak vertical f...
Warner SM, Koch TO, Pfau T.Assessing back movement is an important part of clinical examination in the horse and objective assessment tools allow for evaluating success of treatment. Objective: Accuracy and consistency of inertial sensor measurements for quantification of back movement and movement symmetry during over ground locomotion were assessed; sensor measurements were compared to optical motion capture (mocap) and consistency of measurements focusing on movement symmetry was measured. Methods: Six nonlame horses were trotted in hand with synchronised mocap and inertial sensor data collection (landmarks: T6, T10,...
Patterson-Kane JC, Rich T.Superficial digital flexor tendon (SDFT) injury in equine athletes is one of the most well-accepted, scientifically supported companion animal models of human disease (i.e., exercise-induced Achilles tendon [AT] injury). The SDFT and AT are functionally and clinically equivalent (and important) energy-storing structures for which no equally appropriate rodent, rabbit, or other analogues exist. Access to equine tissues has facilitated significant advances in knowledge of tendon maturation and aging, determination of specific exercise effects (including early life), and definition of some of the...
Buchner HH, Savelberg HH, Schamhardt HC, Merkens HW, Barneveld A.A kinematic analysis was carried out to compare treadmill and overground locomotion in horses at the trot. Stride variables and limb and trunk movements of 10 Dutch Warmblood horses were measured using the CODA-3 gait analysis system. Overground recordings were made on a rubber ground surface and on an asphalt track. Treadmill recordings were taken after a controlled habituation programme and at the same velocities as measured overground. On asphalt, a shorthened stride duration and a decreased vertical displacement of the withers were found compared with those on rubber ground. On the treadmi...
Capomaccio S, Vitulo N, Verini-Supplizi A, Barcaccia G, Albiero A, D'Angelo M, Campagna D, Valle G, Felicetti M, Silvestrelli M, Cappelli K.The horse is an optimal model organism for studying the genomic response to exercise-induced stress, due to its natural aptitude for athletic performance and the relative homogeneity of its genetic and environmental backgrounds. Here, we applied RNA-sequencing analysis through the use of SOLiD technology in an experimental framework centered on exercise-induced stress during endurance races in equine athletes. We monitored the transcriptional landscape by comparing gene expression levels between animals at rest and after competition. Overall, we observed a shift from coding to non-coding regio...
Eivers SS, McGivney BA, Fonseca RG, MacHugh DE, Menson K, Park SD, Rivero JL, Taylor CT, Katz LM, Hill EW.Intense selection for elite racing performance in the Thoroughbred horse (Equus caballus) has resulted in a number of adaptive physiological phenotypes relevant to exercise; however, the underlying molecular mechanisms responsible for these characteristics are not well understood. Adaptive changes in mRNA expression in equine skeletal muscle were investigated by real-time qRT-PCR for a panel of candidate exercise-response genes following a standardized incremental-step treadmill exercise test in eight untrained Thoroughbred horses. Biopsy samples were obtained from the gluteus medius before, i...
Wagner PD, Gillespie JR, Landgren GL, Fedde MR, Jones BW, DeBowes RM, Pieschl RL, Erickson HH.Arterial hypoxemia has been reported in horses during heavy exercise, but its mechanism has not been determined. With the use of the multiple inert gas elimination technique, we studied five horses, each on two separate occasions, to determine the physiological basis of the hypoxemia that developed during horizontal treadmill exercise at speeds of 4, 10, 12, and 13-14 m/s. Mean, blood temperature-corrected, arterial PO2 fell from 89.4 Torr at rest to 80.7 and 72.1 Torr at 12 and 13-14 m/s, respectively, whereas corresponding PaCO2 values were 40.3, 40.3, and 39.2 Torr. Alveolar-arterial PO2 di...
O'Meara B, Bladon B, Parkin TD, Fraser B, Lischer CJ.There is limited information regarding the number of races and the period for evaluation of outcome which is critical for assessment of SDF tendonitis treatments. Objective: To evaluate the re-injury rate and racing performance of Thoroughbred racehorses that sustain SDF tendonitis in relation to matched controls in terms of number of races post treatment and maximum racing performance ratings before and after injury. Methods: Clinical records and racing histories of 401 racehorses with a first occurrence of SDF tendonitis diagnosed by ultrasonography. Controls were of the same age, sex and we...
Harrison SM, Whitton RC, Kawcak CE, Stover SM, Pandy MG.Storage and utilization of strain energy in the elastic tissues of the distal forelimb of the horse is thought to contribute to the excellent locomotory efficiency of the animal. However, the structures that facilitate elastic energy storage may also be exposed to dangerously high forces, especially at the fastest galloping speeds. In the present study, experimental gait data were combined with a musculoskeletal model of the distal forelimb of the horse to determine muscle and joint contact loading and muscle-tendon work during the stance phase of walking, trotting and galloping. The flexor te...
Starke SD, Willems E, May SA, Pfau T.Trotting a horse in circles is a standard and important part of the subjective equine lameness examination, yet objective data on this form of locomotion are sparse. The aim of this study was to investigate the effect of trotting in a circle on head and trunk movement symmetry. Vertical movements of the head, withers, os sacrum and left and right tuber coxae were measured using inertial sensors as 12 sound horses were trotted on a hard surface in a straight line and in a circle on both reins. Seven asymmetry measures and hip hike were calculated for each horse for at least nine strides of comp...
Pfau T, Stubbs NC, Kaiser LJ, Brown LE, Clayton HM.To determine whether body lean angle could be predicted from circle radius and speed in horses during lunging and whether an increase in that angle would decrease the degree of movement symmetry (MS). Methods: 11 medium- to high-level dressage horses in competition training. Methods: Body lean angle, head MS, and trunk MS were quantified during trotting while horses were instrumented with a 5-sensor global positioning system-enhanced inertial sensor system and lunged on a soft surface. Speed and circle radius were varied and used to calculate predicted body lean angle. Agreement between observ...
Votion DM, Gnaiger E, Lemieux H, Mouithys-Mickalad A, Serteyn D.Within the animal kingdom, horses are among the most powerful aerobic athletic mammals. Determination of muscle respiratory capacity and control improves our knowledge of mitochondrial physiology in horses and high aerobic performance in general. Results: We applied high-resolution respirometry and multiple substrate-uncoupler-inhibitor titration protocols to study mitochondrial physiology in small (1.0-2.5 mg) permeabilized muscle fibres sampled from triceps brachii of healthy horses. Oxidative phosphorylation (OXPHOS) capacity (pmol O(2) • s(-1) • mg(-1) wet weight) with combined Complex...
Cayado P, Muñoz-Escassi B, Domínguez C, Manley W, Olabarri B, Sánchez de la Muela M, Castejon F, Marañon G, Vara E.It is recognised that the amount of psychological stress that an animal encounters determines the degree of response of the hypothalamic-pituitary-adrenal (HPA) axis. In human athletes, the added emotive stress of competition is an important element in the adrenal response. The aim of this study was to examine the effect of show-jumping as well as dressage on stress levels by comparing horses' stress response at a horse show compared to their familiar home. Methods: Fifty-one horses involved in competition were used. EDTA blood samples were collected before exercise, upon arrived to the school...
Thorpe CT, Riley GP, Birch HL, Clegg PD, Screen HRC.Tendon is composed of rope-like fascicles, bound together by interfascicular matrix (IFM). Our previous work shows that the IFM is critical for tendon function, facilitating sliding between fascicles to allow tendons to stretch. This function is particularly important in energy storing tendons, which experience extremely high strains during exercise, and therefore require the capacity for considerable inter-fascicular sliding and recoil. This capacity is not required in positional tendons. Whilst we have previously described the quasi-static properties of the IFM, the fatigue resistance of the...
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...
Stellingwerff T, Decombaz J, Harris RC, Boesch C.Interest into the effects of carnosine on cellular metabolism is rapidly expanding. The first study to demonstrate in humans that chronic β-alanine (BA) supplementation (~3-6 g BA/day for ~4 weeks) can result in significantly augmented muscle carnosine concentrations (>50%) was only recently published. BA supplementation is potentially poised for application beyond the niche exercise and performance-enhancement field and into other more clinical populations. When examining all BA supplementation studies that directly measure muscle carnosine (n=8), there is a significant linear correlation...
Dunnett M, Harris RC.The aim of this work was to test the hypothesis that in vivo carnosine biosynthesis is dependent upon endogenous beta-alanine availability, by studying the effect of sustained dietary beta-alanine supplementation in the horse on the carnosine concentration in types I, IIA and IIB skeletal muscle fibres. The diets of 6 Thoroughbred horses were supplemented 3 times/day with beta-alanine (100 mg/kg bwt) and L-histidine (12.5 mg/kg bwt) for a period of 30 days. Percutaneous biopsies of the m. gluteus medius from a depth of 6 cm were taken on the days immediately before and after the supplementatio...
Witkowska-Piłaszewicz O, Maśko M, Domino M, Winnicka A.In horse racing the most acceptable way to objectively evaluate adaptation to increased exertion is to measure lactate blood concentration. However, this may be stressful for the horse, therefore, a simple, noninvasive procedure to monitor race progress is desirable. Forty Thoroughbreds attended race training, with blood samples collected at rest, immediately after, and 30 min after exercise. The lactate concentration was determined 60 s after blood collection using an Accusport. Thermal imaging of the neck and trunk areas was performed following international veterinary standards from a dista...
Jones JH, Longworth KE, Lindholm A, Conley KE, Karas RH, Kayar SR, Taylor CR.This study investigated mechanisms used by horses and steers to increase O2 uptake and delivery (VO2) from resting to maximal rates and identified the mechanisms that enable horses to achieve higher maximal rates of O2 consumption (VO2max) than steers. VO2 and circulatory variables were measured while Standardbred trotting horses and steers (450-kg body mass) stood quietly and ran on a treadmill at speeds up to those eliciting VO2max. As VO2 increased in both species, heart rate and circulating hemoglobin (Hb) concentration increased, thereby increasing O2 delivery by the circulation, while ca...
Ricard A, Robert C, Blouin C, Baste F, Torquet G, Morgenthaler C, Rivière J, Mach N, Mata X, Schibler L, Barrey E.Endurance horses are able to run at more than 20 km/h for 160 km (in bouts of 30-40 km). This level of performance is based on intense aerobic metabolism, effective body heat dissipation and the ability to endure painful exercise. The known heritabilities of endurance performance and exercise-related physiological traits in Arabian horses suggest that adaptation to extreme endurance exercise is influenced by genetic factors. The objective of the present genome-wide association study (GWAS) was to identify single nucleotide polymorphisms (SNPs) related to endurance racing performance in 597 Ara...
Starke SD, Witte TH, May SA, Pfau T.Gait analysis using small sensor units is becoming increasingly popular in the clinical context. In order to segment continuous movement from a defined point of the stride cycle, knowledge about footfall timings is essential. We evaluated the accuracy and precision of foot contact timings of a defined limb determined using an inertial sensor mounted on the pelvis of ten horses during walk and trot at different speeds and in different directions. Foot contact was estimated from vertical velocity events occurring before maximum sensor roll towards the contralateral limb. Foot contact timings mat...
Munsters CC, Visser KE, van den Broek J, Sloet van Oldruitenborgh-Oosterbaan MM.A good horse-rider 'match' is important in the context of equine welfare. To quantify the influence of repetition and horse-rider matching on the stress of horses encountering challenging objects, 16 Warmblood horses were ridden in a test-setting on three occasions. On each occasion the horse was ridden by a different rider and was challenged by three objects (A-C). Heart rate (HR), heart rate variability (HRV) of horse and rider, and behaviour score (BS) of the horse were obtained for each object and as a total for each test. The horse-rider interaction was evaluated with each combination and...
Hodgson DR, McCutcheon LJ, Byrd SK, Brown WS, Bayly WM, Brengelmann GL, Gollnick PD.Horses were exercised at 40, 65, and 90% of their maximum O2 uptake (VO2max) until moderately fatigued (approximately 38, 15, and 9 min, respectively) to assess heat loss through different routes. Approximately 4,232, 3,195, and 2,333 kcal of heat were generated in response to exercise at these intensities. Of this, approximately 7, 16, and 20% remained as stored heat 30 min postexercise. Respiratory heat loss, estimated from the temperature difference between blood in the pulmonary and carotid arteries and the cardiac output, was estimated to be 30, 19, and 23% of the heat produced during exe...
Morrice-West AV, Hitchens PL, Walmsley EA, Stevenson MA, Whitton RC.Musculoskeletal injuries (MSI) in racehorses are commonly due to bone fatigue, a function of the number of cycles (strides) and the magnitude of load applied to the limb. These parameters can be estimated using speed and distance, with greater than 6000 m/month at a gallop (>14 m/s), in combination with canter distances greater than 44,000 m/month, reported to increase fracture risk. Despite their importance, there are limited data on the distances and speeds horses are exposed to during training. Objective: Estimate training volume at different speeds undertaken by Australian Thoroughbr...
McGivney BA, Eivers SS, MacHugh DE, MacLeod JN, O'Gorman GM, Park SD, Katz LM, Hill EW.Selection for exercise-adapted phenotypes in the Thoroughbred racehorse has provided a valuable model system to understand molecular responses to exercise in skeletal muscle. Exercise stimulates immediate early molecular responses as well as delayed responses during recovery, resulting in a return to homeostasis and enabling long term adaptation. Global mRNA expression during the immediate-response period has not previously been reported in skeletal muscle following exercise in any species. Also, global gene expression changes in equine skeletal muscle following exercise have not been reported...
Lavoie JP, Cesarini C, Lavoie-Lamoureux A, Moran K, Lutz S, Picandet V, Jean D, Marcoux M.There is limited information relating bronchoalveolar lavage (BAL) cytology and cytokine messenger ribonucleic acid (mRNA) expression in racehorses with inflammatory airway disease (IAD). HYPOTHESIS AND OBJECTIVE: We hypothesize that cytokine expression in BAL cells would correlate with cytology. Thus, we evaluated the mRNA expression of selected cytokines in BAL cells in racehorses with exercise intolerance and lower airway inflammation. Methods: Thirty-one client-owned Standardbred racehorses with exercise intolerance. Methods: Prospective, observational study. Cells were obtained by BAL, an...
Plancade S, Clark A, Philippe C, Helbling JC, Moisan MP, Esquerré D, Le Moyec L, Robert C, Barrey E, Mach N.An integrated analysis of gut microbiota, blood biochemical and metabolome in 52 endurance horses was performed. Clustering by gut microbiota revealed the existence of two communities mainly driven by diet as host properties showed little effect. Community 1 presented lower richness and diversity, but higher dominance and rarity of species, including some pathobionts. Moreover, its microbiota composition was tightly linked to host blood metabolites related to lipid metabolism and glycolysis at basal time. Despite the lower fiber intake, community type 1 appeared more specialized to produce ace...
Byrd SK, McCutcheon LJ, Hodgson DR, Gollnick PD.This study examined the effects of acute high-intensity exercise on the rate and capacity of Ca2+ uptake and Ca2+-stimulated adenosinetriphosphatase (ATPase) activity of the sarcoplasmic reticulum and the reversibility of these effects. Thoroughbred horses were run at maximal O2 uptake on a high-speed treadmill until fatigued. Muscle temperatures and biopsy samples were collected at rest, immediately after exercise, and 30 and 60 min after exercise. Blood samples were collected at rest and 5 min after exercise. Muscle and blood (lactate concentration) were three- and fivefold greater than pre-...
