Review Article
Overtraining syndrome in horses
- C M McGowan, D J Whitworth
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- 01 May 2008, pp. 57-65
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Overtraining is a significant cause of poor athletic performance in both human and equine athletes. In humans, overtraining syndrome has been defined as an imbalance between training and recovery manifesting as a syndrome of chronic fatigue and poor performance that may be accompanied by physiological and psychological changes. A similar syndrome has been described in horses using both cross-sectional observations and longitudinal studies with progressively increasing training loads until signs of overtraining were observed. The original cross-sectional studies of overtraining in horses linked the syndrome to increased red cell volume. However, more recent longitudinal studies revealed that overtraining is not always associated with increased red cell volume. Once other causes of poor performance have been ruled out, overtraining syndrome should be suspected in horses with evidence of sustained decreased performance in association with one or more physiological or psychological (behavioural) signs. While no single physiological marker is able to identify the syndrome, accompanying physiological signs in horses may include a decrease in body weight, elevated heart rates during exercise, lower plasma cortisol response to exercise, or elevated muscle enzymes or gamma glutamyl transferase concentrations. Behavioural signs were consistent and an early marker of overtraining syndrome in longitudinal studies in horses, and more research on developing behavioural scores to assist in early detection of overtraining syndrome in horses -as has been achieved for humans- is warranted. Two successful models of overtraining syndrome in horses have been developed, both of which appear to meet the criteria of overtraining syndrome rather than overreaching. Overtraining syndrome in horses is real, reproducible and future research should ensure the criteria for diagnosis of overtraining syndrome are met.
Short Communication
Comparison between a sensor (3D accelerometer) and ProReflex motion capture systems to measure stride frequency of horses on a treadmill
- Kathryn Nankervis, Diana Hodgins, David Marlin
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- 01 November 2008, pp. 107-109
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The most popular techniques used for studying equine kinematics are videographic recording combined with the analysis using a commercial software package or optoelectronic systems based on emission and detection of infrared or visible light. Such systems can be expensive, complicated to use and their use may be restricted to indoor use (in the case of infrared systems) or a limited number of strides when used outdoors. Recently, there has been considerable interest in monitoring motion using inertial measuring systems. The purpose of the present study was to determine the accuracy of the Pegasus system (European Technology for Business Ltd., Codicote, UK), which determines stride frequency directly when mounted on the withers. Eight horses of different breeds and sizes (447–588 kg) were studied at walk, trot and two speeds at canter on a treadmill. Simultaneous measurements of stride were made using the Pegasus and ProReflex motion capture systems. Mean stride frequencies (n = 8 horses) for the ProReflex and Pegasus systems at walk (0.86 ± 0.05 and 0.87 ± 0.05 strides per second, respectively), trot (1.36 ± 0.07 and 1.36 ± 0.07 strides per second, respectively) and canter (7 m s− 1: 1.92 ± 0.05 and 1.92 ± 0.05 strides per second, respectively; 8 m s− 1: 1.93 ± 0.05 and 1.94 ± 0.05 strides per second, respectively) were not significantly different (P>0.05). The mean difference between the two systems for all four speeds was − 0.002 strides per second (lower 95% CI: − 0.016; upper 95% CI: 0.011; P = 0.309). In conclusion, the differences between stride frequency measurements made with the Pegasus and ProReflex systems in horses exercising at walk, trot and slow canter on a treadmill are < 1% and not likely to be of physiological significance.
Innovative exercise device that simulates horseback riding: cardiovascular and metabolic responses
- Mandeep Dhindsa, Jill N. Barnes, Allison E. DeVan, Nantinee Nualnim, Hirofumi Tanaka
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- 01 February 2008, pp. 1-5
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An innovative exercise machine, which mimics the movement of horseback riding, has been made available in the market. As an initial step in characterizing this device, we determined the cardiovascular and metabolic responses to exercise. Twenty apparently healthy subjects rode the device (Equus) on day 1. The upper body exercises were added on day 2, to see whether cardiac and metabolic demands were further elevated (Equus+aerobics). After 10 min of continuous exercise, oxygen consumption increased significantly. In the Equus+aerobics condition, increase in oxygen consumption was significant as early as 4 min into the graded exercise test. Overall oxygen consumption was greater in the Equus+aerobics condition than in the Equus condition (P < 0.05). Oxygen consumption returned to baseline levels within 1 h after the Equus (190 ± 58–188 ± 50 ml min− 1) and Equus+aerobics (198 ± 54–194 ± 43 ml min− 1) conditions. Heart rates increased gradually during the graded exercise tests in both conditions (64 ± 11–78 ± 15 and 65 ± 11–83 ± 12 bpm in the Equus and Equus+aerobics conditions, respectively). Both systolic and diastolic blood pressure (BP) increased significantly 6 min into the graded exercise tests and remained elevated throughout exercise in both the conditions. There were no significant differences in BP responses between the two conditions. These results indicate that the cardiac and metabolic stresses achieved with this exercise device are small.
Research Paper
Effects of pre-exercise intrapulmonary blood inoculation on equine pulmonary function during supramaximal exercise
- Shaun A. McKane, Warwick M. Bayly, Raymond H. Sides, Janene K. Kingston, Ronald F. Slocombe
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- 01 February 2008, pp. 7-13
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This study was designed to determine the effect of 200 ml of autologous blood instilled in the lungs of healthy horses had on gas exchange, maximal oxygen consumption and breathing mechanics during supramaximal exercise, as a model of exercise-induced pulmonary haemorrhage (EIPH). The subjects were six healthy well-conditioned Thoroughbred horses. On four occasions over a 6-week period, six horses were subjected to two bouts of exercise to fatigue per day, each at speeds equated with an oxygen requirement that was 110% of . Prior to the second bout of exercise on each day, the horses underwent bilateral bronchoscopy during which either nothing (control), or 200 ml of saline, plasma or blood was inoculated into the distal airways, divided equally between each lung. Run time to fatigue, and measurements of pulmonary gas exchange and breathing mechanics were made and analysed for the effects of the four treatments (control, saline, plasma and blood). Inoculation of blood significantly reduced pulmonary oxygen exchange, and run time to fatigue. Plasma inoculation caused intermediate effects, adversely affecting arterial oxygen tension but without significantly reducing or run time to fatigue. Saline treatment had no effect. None of the treatments had an effect on ventilatory mechanics. The results of this study suggest that volumes of blood in the order of 200 ml can impair gas exchange and interfere with the ability of horses to exercise at supramaximal intensities. Blood volumes of this magnitude are readily evident endoscopically, and probably reflect a moderate-to-severe level of EIPH, in contrast to previously published studies where the unilateral instillation of 100 ml of blood or less did not affect performance.
The influence of horse gender on eventing competition performance
- T C Whitaker, O Olusola, L Redwin
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- 01 May 2008, pp. 67-72
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The study undertook comparative analysis of horse gender and eventing performance. Limited previous research has investigated the impact horse gender may have on performance. However, many competitors have a preference for one gender over another (normally geldings). The study sampled five levels of the sport (intro, pre-novice, novice, intermediate and advanced) and investigated dependent variable penalty scores within the dressage, show jumping and cross-country phases; additionally, final penalty score, rank in competition and lifetime score were analysed. Results indicated the effect of gender to be limited. Issues relating to sample size, data structure and scoring mechanisms are discussed further.
Short Communication
The effects of training aids on the longissimus dorsi in the equine back
- Suzanne Cottriall, Pattama Ritruechai, James M Wakeling
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- 01 November 2008, pp. 111-114
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This study aimed to determine whether training aids (side reins and a Pessoa) increased the use of the longissimus dorsi when horses are being lunged. Horses were lunged on a circle under four different conditions on the left and right reins in walk and trot, and electromyographic (EMG) and speed measurements were taken using surface EMG at T16 and GPS, respectively. The EMG intensity was substantially greater for the longissimus dorsi on the inside of the circle. Differences occurred in both the timing and the intensity of the EMG between the conditions. At walk, the EMG intensity was the greatest for the control condition and at trot the EMG intensity was the greatest for the control and Pessoa control conditions. It is concluded that the training aids of side reins and a Pessoa do not increase the use of the longissimus dorsi to stabilise the back.
Research Paper
Current management and training practices for UK dressage horses
- J M Walters, T Parkin, H A Snart, R C Murray
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- 01 May 2008, pp. 73-83
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There are many instructional texts for dressage management and training, but little scientific knowledge of these practices. It was hypothesized that there would be an effect of horse competition level on management and training. The objectives were to record rider, horse, management and training information from UK dressage horses and to investigate relationships between the variables. A questionnaire-based study was undertaken in all the UK-registered dressage horses. Data from 2554 respondents showed most riders in groups 7/6 with horses competed at novice medium and trained one level higher. Horses were 164–171 cm and warmbloods were the predominant breed. Age and time in competition increased in training and competing from Preliminary to Prix St George. Horses competed twice per month except at Grand Prix (once per month). Most horses had 15–30 h turnout per week. Ninety-five per cent of horses received non-dressage exercise; hacking was the most common, then lunging and jumping. Non-elite horses were significantly more likely to be hacked/jumped than elite. Horses received dressage training three to four times a week, mean warm-up of 16 min and cool-down 11 min at all levels. Mean training duration was 36 min: 21% walk, 45% trot and 32% canter. Preliminary, Novice, Intermediare I and Grand Prix horses trotted most and cantered least in training. Overall, time spent in transitions (30–39%), specific movements (30–39%), working paces (40–49%), collected (10–19%) and extended (0–9%) varied between levels; elite horses spent more time in collected and less time in working than non-elite. Overall, there were differences in training and management practices between competition levels. This information provides baseline data on which to provide future advice.
Small changes in exercise, not nutrition, often result in measurable changes in bone
- B D Nielsen, H S Spooner
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- 01 February 2008, pp. 15-20
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Skeletal injuries in the equine athlete are a tremendous concern with both economic and animal welfare implications. As a result, much research has focused on improving bone quality through nutritional and exercise interventions. With the recent utilization of biochemical markers, changes in bone metabolism can be monitored. This study examined and compared the response of bone markers and estimates of bone mineral content, in studies with nutritional interventions, with those utilizing exercise interventions. The post hoc analyses suggest that nutritional interventions result in less change to bone markers and bone mineral content than exercise treatments. Of the bone markers examined, osteocalcin correlates most strongly to estimates of bone quality while keratin sulphate, an indicator of cartilage turnover, showed the least correlation. Comparing the results of this study with other published studies, similar findings were observed, suggesting that small alterations in exercise play a greater role in affecting measurable changes in bone metabolism and quality of the equine athlete than do small changes in nutrition.
Inflammatory responses to three modes of intense exercise in Standardbred mares – a pilot study
- E D Lamprecht, C A Bagnell, C A Williams
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- 01 November 2008, pp. 115-125
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The objective of this study was to compare exercise-induced inflammatory responses in horses undergoing three different treadmill exercise tests. Mares completed a graded exercise test (GXT), an interval exercise test (IET) and a repeated sprint exercise test (RSET). Blood and synovial fluid samples were taken 24 h before (PRE) exercise, 20–30 min, 2 and 24 h following exercise (REC). Blood was analysed for total protein, haematocrit and total nitrite concentration. Pro-inflammatory and anti-inflammatory cytokine transcripts were measured in whole blood using quantitative real-time polymerase chain reaction. Synovial fluid was analysed for total nitrite. Mares spent more time at greater than 90% of their maximum heart rate during the RSET than they did for either the GXT or IET. There was an effect of exercise test (P < 0.0001) and exercise test by sample interaction (P = 0.010) for plasma total nitrite. Pro-inflammatory cytokine transcripts and plasma total protein were elevated (P < 0.05) after exercise and there was a higher (P < 0.0001) nitrite concentration in tibiotarsal joints compared with radiocarpal joints. As hypothesised, the higher-intensity exercise test (RSET) resulted in greater nitric oxide responses as well as markers of exercise intensity compared with less intense exercise tests (IET, GXT).
Evidence supporting exercise-induced pulmonary haemorrhage in racing greyhounds
- T S Epp, B Szladovits, A Buchannan, L Gates, P McDonough, D J Padilla, J Smart, H H Erickson, D C Poole
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- 01 February 2008, pp. 21-32
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Exercise-induced pulmonary haemorrhage (EIPH) is a major health concern in performance horses, but the presence and severity of this condition in racing greyhounds has received little attention. While equids and greyhounds share many physiological attributes, there are important structural and functional differences that may help protect greyhounds from EIPH. We tested the hypothesis that greyhounds performing a simulated 503 m race would experience EIPH and that the time course of recovery would be similar to the horse, even though the severity or relative extent as indexed by the concentration of red blood cells [RBCs] in bronchoalveolar lavage (BAL) fluid would be lower in comparison with that demonstrated previously in horses. Greyhound dogs (n = 6) raced on two occasions (separated by 7 weeks) and BAL was performed 1 week before, 2 h after and each week for 4 weeks following each race to examine the [RBC], concentration of white blood cells [WBCs], WBC differentials and haemosiderophages in the lungs. Racing increased 10 min post-exercise venous blood [lactate] to 18.6 ± 0.4 mmol l− 1. No epistaxis or pink froth was observed at the nose or mouth of any of the dogs. The [RBC] in the BAL fluid was increased significantly 2 h post-race (baseline = 109.6 ± 11.7 × 103; post-race = 292.3 ± 69.9 × 103 RBC ml− 1 BAL fluid, P < 0.05) and returned to baseline 1 week post-race (149.2 ± 46.2 × 103 RBC ml− 1 BAL fluid, P>0.05 versus baseline). The number of haemosiderophages was not different for any of the measurement periods. The [WBC] in the BAL fluid decreased from baseline and race values at 2, 3 and 4 weeks post-exercise (all P < 0.05). Alveolar neutrophil concentrations were also decreased from baseline and immediate post-race values for 4 weeks post-race. The increased [RBC] in the BAL fluid post-exercise is consistent with the presence of EIPH in these greyhounds. However, the relative extent of EIPH in greyhounds (as indexed by [RBC] in the BAL fluid), as compared with that in the horse, was mild, and the lack of elevation of WBC suggests that, unlike their equine counterparts, inflammatory airway disease was absent.
Effect of water temperature on heart rate of horses during water treadmill exercise
- K J Nankervis, S Thomas, D J Marlin
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- 01 November 2008, pp. 127-131
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While there have been several studies of heart rates (HRs) of horses during exercise in water, the effect of exercise in water of different temperatures has not been reported. While the increase in HR during exercise is primarily related to the intensity of exercise and therefore metabolic rate, increasing body temperature can also contribute to elevations in HR separate to muscle metabolic activity per se. When exercising in water, as the thermal conductivity is greater than that of air, the temperature of the water can have a marked influence on body temperature and heat exchange compared with exercise in air. The aim of the present study was to investigate the effect of water temperature on HR of horses walking for 16 min on a water treadmill in water up to the height of the scapulohumeral joint. Eight horses were studied in three separate exercise tests in water at 13, 16 and 19°C in a randomised order in an ambient temperature between 4 and 10°C. HR was recorded continuously throughout exercise. Mean HR over the 16 min exercise period was the lowest in 13°C water (79 ± 6 bpm), intermediate in 16°C water (89 ± 7 bpm) and the highest in 19°C water (92 ± 5 bpm). A one-way ANOVA and post hoc least significant difference test comparing mean HRs at each temperature showed that there was a significant difference between HRs in water at 13 and 16°C (P < 0.0001) and in water at 13 and 19°C (P < 0.0001), but not between water at 16 and 19°C (P>0.05). Individual HRs for horses during the first minute of exercise in water of 13°C were significantly different from those in water at 16°C (P < 0.0001) and 19°C (P < 0.0001). The gradients of the log HR–time relationships showed a significant difference between exercise in the latter part of exercise in 19°C when compared with 13°C (t = 34.0, P < 0.05) and 16°C (t = 67.4, P < 0.05), suggesting that cardiovascular drift is likely when exercising in temperatures of 19°C and above. In conclusion, to the best of our knowledge, this is the first study to describe the effect of water temperature in the range of 13–19°C on the HR of horses during water treadmill exercise. Further studies to investigate the effect of different water depth and temperature combinations are indicated.
Feeding management practices and supplement use in top-level event horses
- A O Burk, C A Williams
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- 01 May 2008, pp. 85-93
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The objective of this study was to characterize the nutrition and feeding management practices, including concentrate and supplement use, of three-day event horses prior to and during high-level competition. Subjects were horses competing in one of two divisions at the Jersey Fresh Three-day Event in Allentown, NJ, in 2006 and/or 2007. Body weight and condition score of horses, and feeding management surveys, were completed prior to the start of competition with weight of hay and concentrate taken in 2007. Two sample t-tests were used to compare the data between divisions within each year of the study. For both years, the majority of horses were of the male gender and Thoroughbred breed, aged 11.1 ± 0.3 years. There were no differences between divisions within the year for any of the variables measured. The average numbers of supplements fed on a regular basis to horses competing in the 2006 Concours Complet d'Equitation International (CCI**), 2006 CCI***, 2007 CCI** and 2007 CCI*** events were 4.2 ± 0.4, 4.2 ± 0.3, 4.2 ± 0.5 and 4.3 ± 0.7, respectively. In both years, the most administered type of oral supplement was electrolytes, followed by plain salt and oral joint compounds. The majority of horses in both years did not have any change in their forage and concentrate feeding prior to being transported to the show facility. Feeding practices before and after cross-country varied between years and divisions, but most horses had feed withheld for about 2–4 h prior to the event. The majority of feeding management practices followed research-driven recommendations. However, the relatively high average supplement use per horse raises questions about over-supplementation and/or nutrient interactions in these horses.
Potassium-free electrolytes and calcium supplementation in an endurance race
- T M Hess, K M Greiwe-Crandell, J E Waldron, C A Williams, M A Lopes, L S Gay, P A Harris, D S Kronfeld
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- 01 February 2008, pp. 33-41
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Some of the clinical signs seen in horses during endurance races may result from increases in neuromuscular excitability and are related to plasma [K+] and [Ca++]. The present study aimed to test the following hypotheses: (1) Potassium supplementation will affect plasma [K+] and may result in clinical signs related to neuromuscular hyperexcitability during an 80 km endurance ride. (2) Plasma [Ca++] will reflect dietary cation–anion balance (DCAB) and calcium intake. Feeding with a high DCAB and high dietary calcium content (1.5% total calcium of daily ration) diets would lead to higher plasma [Ca++] during an endurance race than on feeding high DCAB diets with a moderate dietary calcium content (1% of total calcium of daily ration). The current study was undertaken during the 80 km endurance research ride in 2002 in Virginia, USA. Forty volunteer rider–horse pairs participated in the race. During the race, electrolyte mixtures with (EM+K) and without (EM − K) potassium were supplied to 18 and 22 horses, respectively. After the race, the horses receiving EM − K during the race were supplied with a recovery formula containing potassium (EM-REC). The horses were fed in addition to their own forage (hay and pasture) either their own commercial concentrate (CC; 1% calcium, n = 11) or one of two research-supplied concentrates during 3 months preceding the research ride, one concentrate rich in sugar and starch (SS; 2% calcium, n = 15) and the other rich in fat and fibre (FF; 2% calcium, n = 14). Peripheral blood samples were taken the day before, within 3 min of the arrival at the vet checks at 27, 48 and 80 km, and after 3 h of recovery. Plasma samples were analysed for pH, haematocrit (Hct), [Na+], [K+], [Cl− ], [Ca++], [Mg++], total protein (TP) and albumin [alb]. Effects of sampling times, treatments and interactions were evaluated by ANOVA in a mixed model with repeated measures and applied to the 25 horses that completed 80 km. Eliminated horses had their blood sampled before entering the elimination vet check and 3 h after elimination, and were compared with finishing horses by t-test. As the ride progressed, significant increases were found in plasma pH, [Na+], , [TP], [alb], Hct and osmolality; and decreases in [K+], [Mg++], PCO2, [Ca++] and [Cl− ]. Horses supplied with potassium-free, sodium-rich electrolyte formulae (EM − K) had 12.5% lower (P = 0.001) mean plasma [K+], 7.8% lower (P = 0.024) TP and 8.4% lower (P = 0.004) albumin at 80 km, and at 3 h after the race they had 6.8% lower (P = 0.045) TP, when compared with EM+K supplemented horses. Horses fed with SS and FF had higher [Ca++] at 27 (P = 0.027), 56 (P = 0.006) and 80 km (P = 0.022) when compared with horses fed with CC. The lower [K+] in the EM − K group, and the higher [Ca++] in the SS- and FF-supplemented horses may help prevent increases in neuromuscular excitability and related clinical signs. The lower TP and albumin indicate less dehydration in the EM − K group and could help prevent related disorders.
Effects of conjugated oestrogens and aminocaproic acid upon exercise-induced pulmonary haemorrhage (EIPH)
- T S Epp, K L Edwards, D C Poole, H H Erickson
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- 01 May 2008, pp. 95-103
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Aminocaproic acid (ACA) and Premarin® (PRE) are used to treat exercise-induced pulmonary haemorrhage (EIPH) at the racetrack based upon their putative coagulation effects. We hypothesized that neither ACA nor PRE would reduce EIPH because the literature does not substantiate coagulation deficits being manifested in EIPH. Six Thoroughbreds were run from 4 m s− 1 until fatigue (1 m s− 1s × 1 min increments; 6° inclined treadmill) after being treated with placebo, PRE (25 mg) or ACA (5 g) at 2-week intervals in a randomized crossover design. Coagulation and exercise-related variables were measured at rest and maximal effort. EIPH and inflammation were quantified via bronchoalveolar lavage fluid (BALF) 30–60 min post-exercise. EIPH was not altered by either treatment (3.8 ± 1.7 (placebo), 4.6 ± 3.2 (ACA) and 2.4 ± 1.2 (PRE) × 106 RBC ml− 1 BALF; p = 0.12), nor was coagulation. However, inflammation was decreased (5.9 ± 0.9 (placebo), 4.4 ± 0.9 (ACA) and 4.2 ± 0.4 (PRE) × 105 WBC ml− 1 BALF; both p < 0.05). There was a trend for decreased time-to-fatigue (720 ± 27 (placebo), 709 ± 24 (ACA) and 726 ± 28 (PRE) s; p = 0.09 for placebo vs. ACA) and a reduction in plasma lactate (19.5 ± 3.0 (placebo), 14.7 ± 1.0 (ACA) and 17.6 ± 2.5 (PRE) mmol l− 1; p < 0.05 for placebo vs. ACA) following ACA administration. ACA and PRE were not effective in reducing EIPH, and ACA may be detrimental to performance. However, both may mitigate exercise-induced pulmonary inflammation.
Effects on fluid balance, digestion and exercise response in Standardbred horses fed silage, haylage and hay
- S Muhonen, J E Lindberg, J Bertilsson, A Jansson
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- 01 November 2008, pp. 133-142
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The objectives were to investigate the effects on fluid balance, digestion and exercise response in Standardbred horses in race training when feeding silage, haylage or hay-only diets. In experiment (exp) 1, five Standardbred geldings were fed forage-only diets: hay (82% dry matter, DM) and silage (45% DM) for 23 days in a crossover design. Total collection of faeces and urine was performed. In exp 2, six Standardbred geldings were fed forage-based diets: haylage (68% DM) and silage (41% DM) for 17 days in a crossover design. On day 17, an incremental interval exercise test was performed on an oval racetrack. In exp 1, horses drank more on the hay than on the silage diet, but total water intake (drinking+water in feed) was higher and resting values of total plasma protein (TPP) was lower on the silage diet. Total water output per day did not differ and therefore the estimated evaporation was larger on the silage than the hay diet. The apparent digestibility was higher on the silage than the hay diet. In exp 2, heart and respiratory rate, TPP and lactate and blood pH did not differ between the haylage and silage diets during and after the exercise test. In conclusion, feeding silage did not affect faecal water content, but apparent digestibility and estimated evaporative fluid loss were higher on the silage diet compared with the hay diet. The silage did not adversely affect the response to intensive exercise compared with haylage. However, the estimated higher evaporative fluid loss on the silage diet compared with the hay diet might cause an unnecessary challenge during more prolonged exercise.
Research Note
Horse warm-up regimes at two different competitive levels of show jumping: a pilot study
- T C Whitaker, A Mills, L J Duxbury
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- 01 May 2008, pp. 105-106
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Warm-up prior to equestrian competition is considered an essential element of preparation. Little work has been previously published regarding warm-up practices within equine competition in relation to either reducing risk of injury and/or improved performance. This pilot study undertook a comparative investigation into the differences in warm-up practices at two distinctly different levels of show jumping competition. The study indicates that significant differences (P < 0.001) are apparent between the total time spent warming up between the levels of competition. Additionally, differences between various specific elements of warm-up were observed between the two levels.
Research Paper
Comparison of a joint coordinate system versus multi-planar analysis for equine carpal and fetlock kinematics
- M C Nicodemus, H M Clayton, J L Lanovaz
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- 01 February 2008, pp. 43-55
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A kinematic multi-planar analysis (MPA) reduces a subject's three-dimensional motion to two-dimensional projections onto planes defined by a fixed global coordinate system (GCS). An alternative to this kinematic method is a joint coordinate system ( JCS) that describes the three-dimensional orientation of the segments comprising the joint with respect to each other so that the JCS moves dynamically with the horse's anatomy. Therefore, the objectives of this study were to locate where differences may occur between the joint motion measurements made using MPA and those made using JCS and to document why these differences in measurements may occur. A Peruvian Paso was recorded during six walking trials using 60 Hz video camcorders. Skin markers tracked the movements and defined the anatomical axes of antebrachial, metacarpal and proximal phalangeal segments. A JCS was established between the two segments comprising the carpal and fetlock joints to measure flexion/extension, internal/external rotation and adduction/abduction at each joint. The MPA model used two markers aligned on the long axis of each segment and measured flexion/extension angles projected onto the sagittal plane of the coordinate system and adduction/abduction angles projected onto the frontal plane of the coordinate system. Carpal and fetlock flexion/extension angles for the walk were similar for the JCS and MPA (peak absolute difference: carpal joint = 7 ± 4° and fetlock joint = 7 ± 2°), indicating that sagittal plane analysis using MPA is adequate when flexion and extension are the only measurements being made provided the horse's plane of motion is aligned with the plane of calibration. There were relatively larger differences in carpal and fetlock adduction/abduction angles measured using an MPA compared with a JCS. Peak absolute difference between the JCS and MPA adduction/abduction angles occurred at 53% of the stride for the carpus (17 ± 4°) and at 61% of the stride for the fetlock (123 ± 25°). Analysis of the reasons for these differences indicated that the accuracy of frontal plane analysis to measure adduction/abduction is limited by its inability to correct for out-of-plane rotations along the long axis of the segments comprising the joint.
Is the second week post-race an adequate period to assess the effect of a long-term conditioning on digestive physiology in competing endurance horses?
- A G Goachet, C Philippeau, M Varloud, V Julliand
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- 01 November 2008, pp. 143-151
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In human athletes, the physiological effects of physical activity on digestion could differ depending on whether it is a bout of exercise or a long-term conditioning. When the aim is to investigate the effect of long-term endurance training on the digestive physiology in competing horses, animals need to be at complete rest during the digestibility and mean retention time (MRT) measurements. We hypothesized that the resting period allowed to horses post-race, and particularly the second week following an endurance race, could be an adequate period to assess digestive physiology and that measurements would still be representative of the pre-competition status. Nutrient total tract apparent digestibility, total MRT and faecal microbial composition and activity measured before a 90 km endurance race were compared with the data obtained post-race, during the second week of the resting period. No differences in the digestibility coefficients, MRT, faecal pH, lactate concentrations and bacterial counts were observed before and after the endurance race. The propionate proportion was higher and the (C2+C4):C3 ratio was lower during the second week post-race than before the race. Carrying out measurements during the second week post-race provides data close to the pre-race status, and avoids an a disturbed training schedule and unnecessary stress before the race in competing endurance horses.
Pre-competitive levels of arousal and self-confidence among elite and non-elite equestrian riders
- Inga A Wolframm, Dominic Micklewright
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- 01 November 2008, pp. 153-159
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Research into other sports has shown that excessive levels of anxiety can undermine motor function during performance. This study aims to investigate the effects of anxiety and self-confidence on equestrian performance. Forty riders (12 male, 28 female; 15 elite, 25 non-elite; 12 dressage, 17 showjumping, 11 eventing) completed the Revised Competitive Sport Anxiety Inventory 2 (CSAI-2R), which measures the levels of somatic and cognitive anxiety (arousal) as well as levels of self-confidence. Two-way between-subjects MANOVA tests were used to examine competence-by-discipline interactions and gender-by-discipline interactions in CSAI-2R scores. Post hoc analysis was conducted using one-way univariate ANOVA tests. Spearman's rank correlation tests were conducted between each of the CSAI-2R subscales according to competence, discipline and gender. Most important findings include lower somatic arousal and higher self-confidence in elite compared with non-elite riders, with 15.2 ± 4.4 vs. 19.0 ± 5.0, F1,34 = 5.8, P < 0.05; 31.5 ± 4.8 vs. 25.1 ± 7.4, P < 0.01, respectively. Negative correlations between cognitive arousal and self-confidence were found among elite riders, non-elite riders, showjumpers and female riders (r = − 0.69, P < 0.005; r = − 0.41, P < 0.05; r = − 0.52, P < 0.05; r = − 0.33, P < 0.05). Greater riding-specific skills in the elite rider may result in increased self-confidence. Lower levels of somatic anxiety may further increase fine motor skills in elite riders. Practical implications are that non-elite riders would benefit from sport psychological interventions increasing levels of self-confidence and reducing symptoms of somatic arousal to improve performance.
Regional variation in the flexural properties of the equine hoof wall
- A M Goodman, L Haggis
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- Published online by Cambridge University Press:
- 01 November 2008, pp. 161-168
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The equine hoof wall is a hard, keratinous structure that transmits forces generated when the hoof connects the ground to the skeleton of the horse. During locomotion the hoof capsule is known to deform, resulting in an inward curvature of the dorsal wall and expansion of the heels. However, while researchers have studied the tensile and compressive properties, there is a lack of data on the flexural properties of the hoof wall in different locations around the hoof capsule. In this study, the flexural properties and hydration status of the hoof wall were investigated in two orthogonal directions, in different locations around the hoof capsule. The hoof was divided into three regions: the dorsal-most aspect (toe), the medial and lateral regions (quarters) and the heels caudally. Beams were cut both perpendicular (transverse) and parallel (longitudinal) to the orientation of the tubules. Differences in the mechanical properties were then investigated using three-point bending tests. There were considerable differences in the flexural properties around the hoof capsule; transverse beams from the heel were 45% more compliant than those from the toe region. This corresponded with changes in the hydration of the hoof wall; beams from the heel region were more hydrated (28.2 ± 0.60%) than those from the toe (24.2 ± 0.44%; P < 0.01). Regional variation in the water content is thought to help explain differences in the flexural properties. Mechanical data are further discussed in relation to variation in the structure and loading of the hoof wall.