This study examined how horse age and gender, rider gender and individual event affected the performance of horses competing at six selected pre-novice events. Dressage accounted for 63% of penalties accumulated whilst 27.9% of penalties were from the cross-country phase and 9.1% from the show jumping phase. The data highlighted differences in the distribution of penalties between events. Male riders scored 4.5 penalties (P<0.001) less than female riders for cross-country jumping. Mares and geldings showed a very small variation (0.8 penalties) in final mean score for competition; however, stallions' mean score was 12.2 points (P<0.01) lower than mares' and 11.4 points (P<0.001) lower than geldings'. Seven-year-olds scored the fewest mean final penalty points when compared with all other age groups (P<0.001). The strongest correlations were between dressage penalty score and final placing at event, r=0.911 (P<0.01), whilst the weakest was observed between cross-country penalties and final penalty score, r=0.091 (P<0.01). It can be concluded that environmental factors exert a significant influence upon scoring at the pre-novice eventing level, both within phases of competition and over the whole competition.

Genes undoubtedly play a role in the development of a successful athlete. This view has flourished on anecdotes such as the observation of a child who displays the same aptitude for a particular sport as one of their parents, or a pair of sisters who both excel in the same discipline. However, the conclusions made from this type of observation have an obvious limitation: that similar environmental factors may be just as responsible as genetic inheritance in explaining the passage and sharing of talent between family members. Here, we review briefly the salient data showing that genes do play a role in athletic performance, and although the data examining the effect of specific genes are limited, we present data examining the role of the angiotensin-converting enzyme gene in human physical performance.

Routine study of three-dimensional (3D) tarsal kinematics is hampered by errors due to the displacement of skin surface-tracking markers relative to the underlying bones. Reliable kinematics can be obtained with bone-fixed markers, but an accurate, non-invasive method would have more applications. Simultaneous kinematic data from skin-based and bone-fixed markers attached to the tibia and third metatarsus were collected from three trotting subjects. The motion of the skin-based markers was extracted relative to the underlying bone motion tracked using the bone-fixed markers. The 3D skin displacement patterns for the skin-based markers were parameterized using a truncated Fourier series model. These displacements were expressed in terms of the local coordinate system for each bone. Skin displacement artefacts were observed in all three axes of each bone segment, with the largest displacements occurring at the proximal tibia. The mean skin displacement amplitudes in the tibia were 6.7%, 3.2% and 10.5% of segment length, and for the third metatarsus were 2.6%, 1.4% and 3.8% of segment length, for the craniocaudal, mediolateral and longitudinal segment axes, respectively. Skin displacement patterns could be expressed concisely using the Fourier series model. Displacements were also consistent between subjects, which should allow them to be used as a basis for developing a correction procedure for 3D tarsal joint kinematics.

The objective of this study was to apply postural sway analysis to measure balance deficits after intravenous administration of detomidine. Six healthy horses were treated intravenously with detomidine (10 μg kg−1, 20 μgkg−1) and saline in random order, with three days between treatments. Postural sway was measured immediately after administration and at 15 min intervals until 120 min had elapsed. Horses stood squarely with all four hooves on a force platform, while the location of the centre of pressure (COP) was recorded continuously for 10 s at 1000 Hz. Five 10 s recordings were analysed and average values calculated for mediolateral COP range of motion, craniocaudal COP range of motion, mean COP radius, COP area and mean COP velocity. All COP variables increased immediately after sedation, but generally returned to normal limits within 15 and 30 min of detomidine administration at 10 and 20 μg kg−1, respectively. The head was lowered for at least 90 min after administration. Balance is affected by detomidine and normal balance is regained later after a higher dose. Procedures requiring balance should not be performed within 15–30 min of detomidine administration. COP variables are a good indicator of the effect of sedation on postural sway, but head position is not.

The aim of this study was to investigate rider muscle activity in relation to horse movement. Electromyographic (EMG) activity of 12 upper-body muscles was recorded simultaneously with the horse's footfall timing for six riders, riding the same horse at trot. Data for five strides were analysed for each rider. Rectus abdominis, upper trapezius, middle trapezius, flexor carpi radialis, biceps brachii, triceps brachii and middle deltoid muscles had constant patterns with two peaks occurring in the same phase of the stride in all riders. Peak EMG values in the upper trapezius and middle trapezius occurred in early stance, and were considered to stabilize the rider's neck and scapula during impact of the diagonal limbs. The rectus abdominis showed peak EMG activity in mid-stance to stabilize the trunk and enable the rider to follow the horse's movement by swinging the pelvis forward as the horse's body reversed direction from downward to upward motion. The triceps brachii, which was active during late stance, and the biceps brachii, which was activated early in stance, stabilized the rider's hands and maintained contact with the bit. Teres major, extensor carpi ulnaris and serratus anterior muscles had a small range of activity (33, 26 and 37%, respectively), consistent with tonic activation or were inactive, suggesting that their function may be related to general postural control.

Physiological studies of elite and sub-elite black South African runners show that these athletes are typically about 10–12 kg lighter than white athletes and that they are able to sustain higher exercise intensities for longer than white runners. Such superior performance is not a result of higher V O2max values and hence cannot be due to superior oxygen delivery to the active muscles during maximal exercise, as is predicted by the traditional cardiovascular/anaerobic/catastrophic models of exercise physiology. A marginally superior running economy is also unlikely to be a crucial determinant in explaining this apparent superiority. However, black athletes are able to sustain lower rectal and thigh, but higher mean skin, temperatures during exercise. Furthermore, when exercising in the heat, lighter black athletes are able to maintain higher running speeds than are larger white runners matched for running performance in cool environmental conditions. According to the contrasting theory that the body acts as a complex system during exercise, the superiority of black African athletes should be sought in an enhanced capacity to maintain homeostasis in all their inter-dependent biological systems despite running at higher relative exercise intensities and metabolic rates. In this case, any explanation for the success of East African runners will be found in the way in which their innate physiology, training, environment, expectations and genes influence the function of those parts of their subconscious (and conscious) brains that appear to regulate the protection of homeostasis during exercise as part of an integrative, complex biological system.

This study aimed to produce a weight-independent algorithm for determination of body surface area (BSA; cm2) to within 5% accuracy of the directly determined value in selected horses and ponies under field conditions. Quantification of BSA in equines has applications in the fields of energy budgeting, growth, thermoregulation, conformation and drug kinetics. A simple algorithm for determining BSA to ±5% accuracy was produced for Shetland ponies, Shire horses, Welsh Mountain Section A ponies and Hanoverian mature horses and foals. The accuracy of the method was ±8% for Welsh Mountain-type ponies and Hanoverian two-year-olds. The data were produced by tiling of the shoulder region on one side of the animal with chalk and adapting a simple geometrical integrative technique. Linear anthropometric measurements were of limited use in predicting BSA in that they produced algorithms of ±5% accuracy for ponies of uniform conformation only (Welsh Mountain Section A ponies). The relevant equations were:for Arab-based breeds (Welsh Mountain-type and Section A ponies and Hanoverian horses and foals) andfor UK native breeds (Shetland ponies and Shire horses), where ‘surface area of shoulder region on one side’ was defined by the anterior margins of the supraspinatus and deep pectoral, and the posterior margin of the triceps muscles. This tiling procedure fulfilled the aim of the study and also provided quantitative information on proportional differences in areas of body regions between and within these selected breeds.

The present study tested the hypothesis that multi-frequency bioelectrical impedance analysis (MFBIA) can be used to provide reasonable estimates of body mass, total body water (TBW), extracellular fluid volume (ECFV) and plasma volume (PV) at rest, during exercise-induced dehydration and subsequent recovery. Seven exercise-conditioned horses were administered indicators for measurement of resting TBW, ECFV and PV. MFBIA measurements at 24 frequencies between 5 and 280 kHz were obtained at rest, during prolonged submaximal exercise and for up to 13 h of recovery with food and water provided. Impedance–frequency response curves were described by a double-exponential decay equation from which coefficients were used, together with height and length, to generate predictive equations for estimating body mass, TBW, ECFV and PV. Predictive equations for body mass, ECFV and PV provided reasonable estimates of the parameter at rest and during exercise and recovery that were within 6% of absolute values determined using indicators. Despite the inherent error in estimating absolute volumes, the technique allowed accurate (within 1%) determination of the change in compartment volumes within individual horses over time. The number of frequencies at which impedance was measured could be reduced to seven without sacrificing the accuracy of the impedance–frequency relationships or the predictive equations – this enabled a 70% reduction in data-acquisition time (to ∼35 s) for each MFBIA measurement series. It is concluded that MFBIA can be used in individual horses to track changes in compartmental hydration status resulting from dehydration and rehydration.

This study explored the relationship between speed-of-sound (SOS) measurements and the material properties of metacarpal bones in order to validate a device that uses linear unicortical transmission of ultrasound. SOS, ultimate tensile strength and modulus of elasticity were determined at nine experimental sites. Measurements of SOS and bone mineral density were collected at three of the nine experimental sites. Twenty-five equine metacarpal (MC3) bones were used. Micro-computerized tomography was used to validate testing protocols. SOS measurements were highly site- and horse-dependent. One or more statistically significant correlations were found with ultimate tensile strength, modulus of elasticity and bone mineral density in four of the nine experimental sites. A previously described pattern of high lateral and medial cortical stiffness and SOS was found in the mid-diaphysis that correlated with bone mineral density (r2=0.25, P<0.01) and modulus of elasticity (r2=0.14, P<0.05). SOS and ultimate tensile strength correlated strongly in the distal dorsal metacarpus (r2=0.47, P<0.001). Lateral and medial distal-level sites just above the fetlock joint had a variable amount of cancellous bone, reducing the ultimate strength of these sites. The study indicates that quantitative ultrasound is sensitive to differences in the quality of equine metacarpal bone, so this technique may be useful for monitoring adaptation to exercise and bone development.

East African athletes now dominate international distance running events from the 800 m to the marathon. Explanations for their phenomenal success have included optimal environmental conditions for developing distance running performance, psychological advantage and advantageous physiological characteristics. It is well established that genetics plays a role in determining inter-individual differences in exercise performance and adaptation to training stimuli. It is not known, however, to what extent inter-population differences (i.e. between ‘races’ and/or ethnic groups) in exercise performance can be attributed to genetics. There have been considerations that ‘black’ athletes are genetically adapted towards performance, given the concurrent success of athletes of West African ancestry in sprint events. However, the current notion of ‘race’ is not universally accepted, and genetic differences within and between populations are not clearly delineated by geographical or ethnic categorizations. Recent findings from mitochondrial DNA show that the populations from which Ethiopian athletes are drawn have not been isolated populations and are not genetically distinct from other Ethiopians. Y-chromosome analysis of the same population shows concurrent results, although some differences are present between athletes and the general Ethiopian population, suggesting an influence of the Y chromosome on athlete status in Ethiopia. It is concluded that there may be a role for genetics in the success of East African athletes; however, any genetic component to their success is unlikely to be limited to East Africans and is more likely to be found in other populations. At present it is unjustified to implicate a role for genetics in the success of East African runners when no genes have been identified as being important to their performance.

This study investigated the effect of training and exercise intensity on blood antioxidant markers in six healthy Standardbred horses. Markers studied were uric acid (UA), ascorbic acid (AA), α-tocopherol, vitamin A (Vit A), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione – reduced (GSH) and oxidized (GSSG), glutathione redox ratio (GRR), copper (Cu), zinc (Zn) and selenium (Se). The horses performed a standardized exercise test (SET) when they were untrained (T0), after 4 weeks of light training (T4) and after 8 weeks of interval training (T12). Forty-eight hours after SET T4 and SET T12, a SET with run up to fatigue (TTF4 and TTF12) was performed. Maximal oxygen consumption (V˙O2max) was determined within 3–5 days after TTF4 and TTF12. At each test (SET T(i) and TTF(i)), venous blood was sampled at rest (R), peak-exercise (Emax), 15 (E15) and 60 (E60) min after the test. UA, AA and GRR were increased significantly by the exercise, whereas GSH and Vit A were decreased significantly (P<0.05). Training-related increases (T0 vs. T4 vs. T12) were observed for UA, SOD, GPx and Se, whereas GSH, α-tocopherol and Zn decreased (P<0.05). Exercise intensity (TTF(i) vs. T(i)) increased UA and AA significantly and decreased GSH significantly (P<0.05). A significant correlation between ΔSOD and ΔV˙O2max (r=0.86, p<0.05) determined at SET T4 and SET T12 was found. Taken together, these results indicate that training and exercise intensity significantly influence blood antioxidant markers in healthy Standardbred horses.

We hypothesized that hyperlipidaemia, diabetes and diabetic dyslipidaemia increase the contractility of coronary arteries in swine, and that exercise would prevent this enhanced contractility. We further hypothesized that this enhanced contractility is associated with elevated potassium (K+) channel activity, consistent with the idea that certain disease states, as in hypertension, result in a compensatory upregulation in K+ channels. Swine were assigned to one of the following groups: control, standard chow (C; n=6); hyperlipidaemic, high-fat chow (H; n=5); diabetic, standard chow (D; n=7); diabetic, high-fat chow (‘diabetic dyslipidaemic’, DD; n=12); or exercise-trained DD (DDX; n=9). High-fat chow consisted of standard pig chow with added cholesterol (2%) and coconut oil. Endothelium-denuded segments from D, DD and DDX animals showed enhanced contractility to prostaglandin F2α (PGF2α) compared with C, while segments from H, D and DD showed enhanced contractility to endothelin-1 (ET-1) compared with C and DDX (P<0.05). The enhanced contractility was not accompanied by differences in K+ channel contribution to force reduction. There was no effect of the treatments on expression of the endothelin receptor A or endothelin receptor B. A possible mechanism for the enhanced vasoreactivity of coronary arteries of H, D and DD swine is an alteration in the signalling pathways of ET-1- and PGF2α-induced contraction. Exercise prevented the increase in contractility to ET-1, but not to PGF2α, reinforcing the concept of vasoconstrictor specificity.

Scientific investigation of racial athletic aptitude has been preceded by a century of pseudo- and quasi-scientific speculations on this topic. For this reason, physiological and anatomical research on African runners is performed in a social context that is still permeated by folkloric ideas about racial differences, some of which pertain to athletic performance. A powerful stereotype of ‘tropical nature’ and its ‘superabundant’ vitality has influenced non-African thinking about African athletic potential. The idea that evolutionary adaptation in Africa is a particularly severe version of natural selection has had a similar effect on Western thinking about African runners. Romantic ideas about African athletic aptitude may, therefore, be understood as modern versions of the doctrine of black ‘hardiness’ that survives in contemporary biomedicine in various forms.

Exercise is associated with an increase in the production of oxidants that may be instrumental in the development of exertional rhabdomyolysis. We speculated that participation in a long-distance sled race would alter antioxidant capacity of dogs, in conjunction with increases in indices of rhabdomyolysis. The objective was to determine the effect of participation in a long-distance sled dog race on antioxidant capacity and plasma creatine kinase (CK) activity in sled dogs. This was a prospective, longitudinal study on a convenience sample of 57 Alaskan sled dogs participating in a 1600 km sled dog race. Blood samples were collected before racing (31 dogs) and after racing (39 dogs) for measurement of plasma vitamin E concentration; CK, aspartate aminotransferase (AST) and caeruloplasmin (CER) activity; and red-blood-cell (RBC) glutathione peroxidase (GPX) and superoxide dismutase (SOD) activity. CER and GPX activities after the race were 26% and 14% lower, respectively, than before racing whereas CK and AST were 300% and 170% greater. There was no change in plasma vitamin E concentration or RBC SOD activity. We conclude that completion of a long-distance sled dog race involving prolonged and repeated submaximal exercise results in a reduction in enzymatic antioxidant activity in the blood of sled dogs.

Kenyan runners, and especially those originating from the Kalenjin tribe, have dominated international middle- and long-distance running for over 40 years, prompting significant interest in the factors contributing to their success. Proposed explanations have included environmental factors, psychological advantage and favourable physiological characteristics, which may be genetically conferred or environmentally determined. Running is inherent within local Kenyan tradition and culture, and the Kenyan way of life, which involves many outdoor activities and pastimes in addition to mostly unfavourable living conditions, is conducive to enhanced distance running performance. Despite economic deprivation, Kenya has produced world and international running champions repeatedly over the past few decades; these champions have become role models for the younger generations, who take up running in the hope of a better future for themselves. Favourable environmental conditions such as altitude, diet and anthropometry, in addition to the motivational and socio-economic factors mentioned above, have all been proposed as possible reasons for the unsurpassed achievements of Kenyan distance runners. However, the fact that the majority of internationally successful runners originate from a small tribe that accounts for approximately 3% of the total Kenyan population also points to a possible genetic component. Whether this is subject to influence from other co-factors, such as altitude or training effects acquired during childhood, remains as yet unresolved.