Few studies exist regarding the physiological responses of equestrian riders during actual or simulated competition. Interest has proliferated in recent years on the responses of riders, which is mainly due to the fatal tragedies that occurred in eventing in the late 1990s. More emphasis is also being placed on the importance of riders, fitness in order to improve athletic performance at the international level. The aim of the present study was to investigate the fitness and exercise capacity of female equestrian athletes, and to relate this to the metabolic requirements of dressage (DR), showjumping (SJ) and cross-country (XC) phases of the one-day event. Sixteen female collegiate riders (age = 24.5 ± 7.7 years; height = 166.6 ± 3.8 cm; weight = 60.4 ± 6.0 kg) competed in a simulated Horse Trials Pre-Novice competition riding either their own horse or one familiar to them. Anthropometric data were obtained for each rider (body mass index (BMI) = 21.7 ± 1.9; % body fat (BF) = 23.4 ± 5.3; lean body mass (LBM) = 48.5 ± 3.6). Each subject successfully completed all three phases of the event. There was a progressive increase in oxygen consumption (VO2) during the three phases (DR, SJ and XC) from a mean value of 20.4 ± 4.0 ml kg− 1 min− 1 (DR), 28.1 ± 4.2 ml kg− 1 min− 1 (SJ) to 31.2 ± 6.6 ml kg− 1 min− 1 (XC) (P < 0.001). Heart rate data showed a similar trend from a mean value of 157 ± 15 beats min− 1 (DR), 180 ± 11 beats min− 1 (SJ) to 184 ± 11 beats min− 1 (XC) (P < 0.001). Mean lactate concentration increased progressively from resting values: rest 2.5 ± 1.3 mmol, DR 4.8 ± 1.8 mmol, SJ 7.8 ± 2.4 mmol and XC 9.5 ± 2.7 mmol (P < 0.001). Urine osmolality was significantly (P < 0.001) increased from a pre-competition mean of 0.488 ± 0.270 mOsmol l− 1 to a post-competition mean of 0.684 ± 0.230 mOsmol l− 1. Mean hand grip strength was observed to decrease significantly (P < 0.01) from a pre-value of 32.3 ± 6.3 kg to a post-value of 29.8 ± 5.5 kg. Mean weight loss pre- to post-competition was 1.6 ± 1.1% body weight (P < 0.01). In conclusion, the study emphasises the variability in metabolic cost between riders performing in the same simulated competition but riding different horses, and highlights the difference in metabolic demand between the different phases.

The gaits of the dressage horse have been described, but less information is available regarding the transitions between gaits. The objective was to describe and compare temporal variables during transitions from trot to halt (TH) and halt to trot (HT) in horses competing in different levels of dressage competitions. The experimental hypothesis was that a higher level of training is associated with the ability to make more direct transitions with fewer non-trot steps. Video recordings of TH and HT transitions were made during novice (n = 15 horses), medium (n = 15 horses) and advanced (n = 15 horses) dressage competitions and were analysed to determine the timing of footfalls and lift-offs. Duty factors, diagonal dissociations and suspension durations were calculated for eight diagonal steps preceding and following the halt. The steps were classified as trot or non-trot based on diagonal synchrony of the footfalls. Statistical analysis using a general linear model ANOVA with Tukey B post hoc tests indicated that advanced horses changed their limb coordination patterns more abruptly, and that they maintained positive diagonal dissociation and a suspension phase in the steps in closer proximity to the halt than the novice horses. There was no preference between left/right and fore/hind limbs in the order of limb placements in the TH transition. The first limb to move off from the halt was always a forelimb, with a significant preference for the right forelimb in the advanced horses.

This study tested two hypotheses. First, that moderate exercise would alter maternal and foetal heart rate (HR) in the horse. Second, that pregnancy would alter the HR, plasma cortisol and plasma lactate response to moderate exercise in mares. Six unfit, pregnant Standardbred mares (6–19 years) underwent two incremental graded exercise tests (GXT). The first GXT was performed at approximately 9 months of gestation, which represents c. 80% of the total pregnancy time, and the second GXT at approximately 6 months post-parturition. During the GXT, mares ran on a treadmill up a fixed 6% incline completing three 1 min steps at velocities of 4, 6 and 7 m s− 1. Maternal HR was obtained via both electrocardiograph (ECG) and the ventricular waveform obtained from a micromanometer catheter. Data were recorded at rest, at 4, 6 and 7 m s− 1 of the GXT and at 0, 1, 2, 3, 4 and 5 min post-GXT. Foetal HR rate was measured via ECG before, immediately after and at 1, 2, 3, 4 and 5 min post-GXT. Radioimmunoassay (RIA) kits were used to measure plasma cortisol concentration in samples collected before the GXT, immediately after exercise and after 5 min of recovery. Plasma lactate concentrations (LA) were measured at rest, at 4, 6 and 7 m s− 1 and at 5 min post-GXT. Plasma cortisol concentrations were measured using RIA and the samples collected at rest, immediately after and at 5 min post-GXT. Exercise caused no change (P>0.05) in foetal HR. Maternal HR, plasma LA and plasma cortisol concentration were greater (P < 0.05) during the post-parturient GXT compared with the pre-parturition GXT. Body weight (mean ± SE) was lower after parturition (570 ± 20 vs. 505 ± 22 kg; P < 0.05). Consequentially, there were differences (P < 0.05) in work rate (watts) at each step of the GXT (1557 ± 53 vs. 1381 ± 60; 2339 ± 80 vs. 2071 ± 90; and 2571 ± 121 vs. 2416 ± 105 W). These data suggest that mares benefit from greater cardiovascular efficiency during pregnancy. Additionally, the lack of a change in foetal HR suggests that the unborn foal is not stressed during moderate maternal exercise.

Previous studies of the effect of age on maximal aerobic capacity (maximal rate of oxygen consumption, VO2max) in horses have only grouped horses (young, middle-aged and old) for statistical analysis. Those experiments were not designed to determine a break point due to age. The purpose of this study was to utilize data collected over the last 15 years to test the nature of the association between age and VO2max, and secondarily, to determine whether there is a ‘breakpoint’ in the age-related decline in aerobic capacity. Data were acquired from 50 unfit Standardbred mares ranging in age from 4 to 29 years, and were used in a retrospective regression analysis in order to characterize the age-related decline in VO2max. All VO2max values were measured using the same incremental graded exercise test protocol. The data were analyzed using a curvilinear regression analysis predicting VO2max from age, and the break point was determined using univariate simple contrasts. There was a significant decline in VO2max with age (R2 = 0.554; P < 0.001). The data analysis demonstrated a notable downturn in cardiopulmonary function between the ages of 18 and 20 years (P < 0.001). Such results indicate similar responses to age between humans and horses. These results have implications for improving training methods in active older horses.