Ten mature Standardbred mares (9–13 years, ~522 kg) were used to test the hypothesis that pelleted dietary supplementation would alter total plasma bicarbonate (tCO2) concentrations. All the mares used in this study were unconditioned, but were familiarized to the laboratory setting and running on a treadmill. Each of the ten mares was semi-randomly assigned one of four dietary treatments. The four treatments (oats as control and three pelleted feed supplements: Drive, Omolene and Strategy) were administered in a crossover fashion throughout a 4-week testing period. These products were chosen based on the frequency of their use by Standardbred/Thoroughbred owners and trainers in New Jersey. The horses underwent a simulated race test (SRT) on a treadmill (6% grade) at the end of each administration period. During the SRT, horses ran for 2 min at 4 m s− 1, 2 min at the speed previously shown to correspond to VO2max and 2 min at 4 m s− 1. Blood was collected before supplement treatment ( − 4 h), 10 min prior to exercise and at 0, 60 and 90 min post-exercise. Plasma concentrations of bicarbonate, sodium, potassium and chloride were measured using a Beckman ELISE analyser. The major finding of this study indicates that the plasma [tCO2], chloride and sodium concentrations were not altered by the dietary supplements studied (P>0.05). There were differences (P < 0.05) in plasma [tCO2] across sampling intervals ( − 4 h, − 10 min, +0 min, +60 min and +90 min) that were attributable to acute exercise (mean ± SE: 34.4 ± 0.9, 33.2 ± 1.1, 20.2 ± 0.8, 31.5 ± 0.8, 30.3 ± 1.6 mmol l− 1). There was a slight effect of treatment (P < − 0.05) on potassium levels. However, exercise was the main factor that caused substantial changes (P < 0.05) in the plasma tCO2, potassium, haematocrit and total protein concentrations. It was concluded that the pelleted diet supplements examined do not alter plasma [tCO2] in horses.

Nations intending to send teams to compete in the equestrian sports at the 2008 Olympic Games in August in Hong Kong were concerned that safe competition would not be possible in this environment. Our objective was to demonstrate that horses could safely compete in the Hong Kong climate, where identifying and treating dehydration and electrolyte losses would be especially important to horse welfare. We hypothesized that evaluating serial changes in body weight, urine specific gravity (USG), urine Na concentration (UNa) and urinary clearance of Na (CLNa) would allow us to identify dehydration and Na deficits. Seventeen horses were housed in air-conditioned stables maintained at 25°C. Vital signs and body weight were recorded twice daily. Twenty-four-hour water consumption, and number and duration of exercise periods, were recorded daily. Haematological and biochemical variables, USG, UNa and CLNa, were measured intermittently in subsets of horses. Environmental conditions were monitored daily. Fifteen horses completed the competition; vital signs and all mean values for haematological and biochemical variables (except a high mean total protein on day 1 after arrival) remained within reference ranges. Daily water intake was (mean ± SE) 38 ± 1.5 l (range 18–74 l). Mean change in body weight during the entire study was − 3 ± 2.4 kg (range − 17 to 14 kg). Horses spent at most 3.5 h outside and at least 20.5 h in the stables daily. The mean value for USG was 1.035 ± 0.0008 and 57% of determinations were >1.035. The mean UNa was 61 ± 8 mmol l− 1 and 57% of values were ≤ 20 mmol l− 1. The mean CLNa was 0.14 ± 0.0.04%, with 76% of determinations being ≤ 0.1%. An 88% completion rate demonstrated that safe competition was possible. Access to climate-controlled stables probably helped to minimize daily fluid and electrolyte losses, and facilitated recovery following exercise. A majority of USG values >1.035, UNa < 20 mmol l− 1 in 29% of determinations, and CLNa < 0.1% in 57% of determinations suggested that some horses may have had insufficient Na intake while in Hong Kong. Monitoring USG, UNa and CLNa may aid in identifying and treating fluid and Na deficits in competition horses.

In a previous study of young Norwegian–Swedish coldblooded trotters (NSCT), aged 17–24 months, a high proportion (>30%) of type I fibres in the gluteus medius was found in 33 of 141 horses. These findings were surprising and the purpose of the present study was to find an explanation for the high type I fibre proportion in these horses. Possible explanations might be an inaccuracy in the procedure of analysing the biopsy sample, inaccuracy in the method of sampling or a muscular disorder in these individuals. Further, the high type I fibre proportion might be age related. The accuracy of the procedure for determination of the fibre composition from a biopsy sample was tested by analysing the same biopsy sample at two different occasions in nine horses. Four of the nine horses had high type I fibre proportions on both occasions and the five others had proportions within the expected range on both occasions. The repeatability of the procedure was tested by an agreement analysis, where the agreement index (AI) is calculated. This analysis revealed an AI of 0.70, where an AI >0.5 shows a good repeatability. Eight of the nine horses were re-sampled at the age of 3 years. At this age, all horses had type I fibre proportions < 30%. The biopsy technique with an absolute depth of 4 cm might give a relatively more superficial sample of the muscle in larger horses, which may explain the age-related differences. However, in young horses, high proportions of type I fibre seemed to be found in the larger individuals. The light sedation given to the horses before sampling may also have influenced the relative sampling depth. Muscular disorders were ruled out as performances in the 3-year season did not differ between 33 horses with high type I fibre percentage and 106 horses with normal type I fibre percentage. In conclusion, the high proportion of type I fibres in some young NSCT was not caused by the analysing procedure or by muscular disorders, but is probably related to the sampling point within the muscle.

To determine the incidence of abnormal or delayed systolic blood pressure recovery (SBPR) in relation to the level of adiposity in the adult population; the risk of delayed SBPR in overweight/obese adults relative to their non-overweight/obese controls; and the best predictor of third-minute systolic blood pressure (SBP) ratio and delayed SBPR among four obesity indices – body mass index (BMI), waist circumference, waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR). Two hundred and ninety-six apparently healthy adults aged 18–48 years participated in the study. Anthropometric variables were measured, and subjects performed cycle ergometer exercise at 80% age-predicted maximum heart rate. Blood pressure (BP) and heart rate were measured before and during exercise. BP was further measured immediately after exercise and subsequently at 2 min intervals until recovery to resting position. The incidence and risk of delayed SBPR were higher in the overweight/obese individuals than those in the non-overweight/obese controls. Multivariable regression analyses revealed that BMI in males and WHtR and WHR in females had the strongest relationships (P < 0.05) with post-exercise SBPR. WHtR and BMI had the strongest associations with increased risk of delayed SBPR in the non-overweight/obese and the overweight/obese individuals, respectively. The present findings suggest that WHtR in the non-obese individuals and BMI in the overweight/obese individuals may be the best obesity variables for the prediction of abnormal post-exercise SBP response. Our findings further suggest that a reduction in body weight through healthy activities such as exercise may reduce the incidence and increased risk of delayed SBPR and its associated cardiovascular risks.

This study investigates the relationship between Thoroughbred yearling sale price and race performance at the age of three. Sales details of all yearlings sold at Tattersalls October Yearling sales (Newmarket, UK) and Goffs Yearling sales (County Kildare, Ireland) in 2004 and 2005 were collected. End-of-year Timeform ratings were used to measure racetrack performance at the age of three. Yearlings that did not meet the study's criteria were excluded from the statistical analysis, reducing the sample size from 5749 to 1735. Comparisons between Tattersalls and Goffs were made for sale prices and end-of-year Timeform ratings. Tattersalls had a greater average sale price (56 787.51 guineas) than Goffs (52 680.49 guineas). Average end-of-year Timeform ratings were extremely similar for those yearlings sold from Tattersalls (78) and Goffs (77). A very highly significant correlation between LOG yearling sale price and end-of-year Timeform rating at the age of three (r = 0.363, n = 1735, P < 0.001) was established. Yearling sale price accounted for 13.3% of the variation in end-of-year Timeform ratings at the age of three (P < 0.01). A regression equation was formulated, allowing end-of-year Timeform rating at the age of three to be predicted from yearling sale price.

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.

Foot impact force during running has been suggested as one of the important causes of haemolysis in runners. However, intravascular haemolysis has also been reported among athletes involved in sports in which foot impact does not occur. The purpose of our study was to analyse intravascular haemolysis in athletes during running and compare it with cycling. Twenty male long- and middle-distance runners volunteered to participate in this study. They were divided into two groups (group 1: running and group 2: cycling), with 10 participants in each group. Each athlete completed 1 h of running or cycling at their calculated target heart rate (60–70%). Venous blood samples were collected before and immediately after the running and cycling protocols. Unconjugated bilirubin (UBR; P < 0.01) and lactate dehydrogenase (LDH; P <0.05) levels were increased significantly after running, indicating the occurrence of haemolysis in this group of athletes. A significant variation was observed in the mean values of haematological variables between post-run (UBR: 1.40 ± 0.29, LDH: 225 ± 69.13, haemoglobin (Hb): 11 ± 1.09) and pre-run (UBR: 0.88 ± 0.31, LDH: 183 ± 40.42, Hb: 12.10 ± 1.19) during the running protocol. No significant differences in haematological variables were found between athletes who did cycling and non-exercising group participants. Our results indicate that intravascular haemolysis occurred significantly during running when compared with cycling. Hence, we conclude that the mechanical trauma due to footstrike is the major cause of intravascular haemolysis during running.

Studies investigating the role of oxidative stress in both the ageing process and osteoarthritis (OA) in human beings are limited by the unavailability of samples from healthy subjects. OA occurs naturally in the horse and has been used as a model of human OA. The objective of this study was to determine the effect of ageing and OA on the non-enzymatic synovial fluid antioxidant status of the horse. The concentrations of ascorbic acid, dehydroascorbate (DHA, oxidized ascorbic acid), uric acid, glutathione, α-tocopherol and thiobarbituric acid reactive substances (TBARS) were determined in paired synovial fluid and plasma samples from 25 horses aged between 3 and 25 years. Osteoarthritic lesions were scored from 0 (healthy) to 4 (severe OA). Glutathione was not detectable in synovial fluid. Neither plasma nor synovial fluid antioxidant concentrations were affected by age. Ascorbic acid concentrations in plasma correlated strongly with those in synovial fluid from both healthy (P < 0.001) and diseased joints (P = 0.003). Synovial fluid concentrations of ascorbic acid and uric acid were not influenced by OA compared with healthy joints. However, the concentration of DHA was slightly, but significantly, elevated in synovial fluid from joints with severe OA (95% CI: [2.2, 11.8] μmol l− 1; P < 0.001). OA is associated with only a mild oxidative burden, which does not appear to overwhelm the synovial fluid antioxidant capacity. Consequently, antioxidant supplementation is unlikely to have a beneficial effect in the treatment of OA.

The primary purpose of this study was to test the predictions of the dual-mode model using arm ergometry as the exercise modality. It was hypothesized that changes in affect during exercise would be greater in high (105% VT)- and low (80% VT)-intensity exercise conditions than in a control condition, while differences in affect would be observed between exercise conditions. Study participants were 24 physically active men. A within-subjects design was used. Affect was measured using the Activation–Deactivation Adjective Check List and the State Anxiety Inventory. Cognitive (i.e. self-efficacy and enjoyment) and physiological (i.e. heart rate, pain and perceived exertion) mediators of the exercise–affect relationship were also examined. Results showed that during exercise, changes in affect were greater in the exercise conditions than the control condition, and affective valence in the exercise conditions declined relative to the control condition. In partial support of the dual-mode model, self-efficacy mediated the relationship between below-VT exercise and affect, whereas pain mediated the relationship between above-VT exercise and affect. These findings highlight the importance of exercise intensity to the affective benefits of exercise.