At the International Conference on Equine Exercise Physiology (ICEEP7), about 70 people attended the workshop on workload and conditioning guided by the authors. Most of the audience were involved in Thoroughbred or Standardbred racing, and only a limited number of people were mainly involved in FEI equestrian disciplines (sport horses). The workshop and this review article address the measurement of workload and conditioning of the Thoroughbred racehorse. It was proposed that workload could be quantified using a few selected parameters commonly recorded in the racing industries, such as velocity and distance, to generate a cumulative workload index. The review of conditioning focuses on the Thoroughbred racehorse and examines what can be modified with training, how training programmes should be designed based upon scientific methods and how training programmes should be routinely designed in current practice. It would appear that, in general, the methods used in practice for training Thoroughbred racehorses are quite similar to those used in a set of recent scientific studies, particularly in young (2–3-years-old) Thoroughbreds. Nevertheless, both the length of the training programme and the total amount of exercise are usually shorter/lower than ideal in order to maximize physiological adaptations within the animal's body. In planning the training programme, it is very important to recognize that different adaptations occur at different rates, and this will affect the relative amount of training that should be applied to achieve specific adaptations.

Feeding regimens for horses are usually based on perceived workload (PW) together with body condition. This can lead to inappropriate energy intake and, in particular, excess weight. Therefore, a more detailed understanding of the factors influencing individual energy needs under practical field conditions would be valuable. The purpose of this study was to evaluate to what extent the variations in actual versus PW may influence the estimated energy intake required to maintain body weight (BW) in individual animals. Eight mature, experienced riding school horses, chosen at random and maintaining a constant BW, were observed in standard flat work lessons with four different instructors at an equine training college. Heart rate (HR) and the structure of the lessons were recorded. Relative workload (RW) was determined for each horse by dividing its average HR per lesson by its estimated maximum HR (HRmax). PW was estimated by each instructor for each horse using a scale of 1–5. One-way ANOVA and t-test were used to determine the differences and Spearman's and Pearson's correlations were used to determine the correlations. The mean estimated RW was 39.1% of the estimated HRmax ( ± 5.7%) and was not significantly different between instructors (P>0.05). Rider weight as a percentage of BW showed a weak but statistically significant positive correlation with mean HR (r2 = 0.14, P < 0.05). Estimated energy intake was negatively correlated with BCS (r2 = 0.65, P < 0.001) and differed significantly (P < 0.05) between light (BW = 455–532 kg) horses (mean 0.18 ± 0.04 MJ kg− 1 BW) and heavy (BW = 622–660 kg) horses (mean 0.15 ± 0.03 MJ kg− 1 BW). No difference was found in estimated energy intake between different workloads (flat work only or flat work and jumping) (P>0.05). When BW was compared with estimated energy intake, no relation was found either (P>0.05). These results suggest that the amount of energy needed to maintain BW in individual horses cannot necessarily be estimated simply on the basis of the intensity and the duration of structured exercise. Other factors including age, individual digestive and metabolic efficiency, body condition and possibly the energy utilized through non-structured activity (e.g. box walking) may need to be taken into account.

Regular monitoring of the heart rate (HR):speed relationship may help evaluate response to training and aid in the early detection of problems. This relationship is normally determined using a treadmill or via a ridden test conducted outside on a track. Simple practical alternative methods to obtain this relationship without access to a treadmill or a track could be of value in the field. To evaluate whether the HR:speed relationship could be determined via an indoor ridden test or a lunge test, HR was monitored on two occasions at least 3 h apart, in 12 adult horses (mixed breed) in a familiar environment during a 5 or 7 m radius circle lunge (unridden) test (5LT or 7LT) and an incremental (ridden) test (RT) on the same day. The RT comprised two ridden laps of the perimeter of a 60 × 40 m indoor school at walk, three laps at trot, three at medium canter and four at fast canter (all on the right rein). The speed of each lap was recorded. The LT comprised lunging for 2 min on each rein at walk, trot and canter. Speed was determined from the number of laps completed and measurement of the distance travelled. HR and speed were highly correlated in both lunge and ridden tests (both r = 0.99 ± 0.01). V140 on the ridden test (5.2 ± 0.6 m s− 1) was significantly greater than on the pooled lunge test data (4.4 ± 0.6; P < 0.0001). There was a negative correlation between recovery HR at 2 min following either the LT or RT and V140 (P < 0.05). The slope of the HR versus speed relationship and V140 were not different between RT and 7LT, but were significantly different from those of the 5LT (P < 0.05). V140 was always lower on the lunge tests compared with the ridden test. This suggests that, in this study, lunging without a rider increased the metabolic demand above that for being ridden at a similar speed. V140 determined by the 7LT gave the closest approximation to the V140 determined by the RT. The HR:speed relationship can be obtained either from riding an incremental test in an indoor school or from an unridden lunge test.

Osteocalcin (OC), bone fraction of alkaline phosphatases (BAP) and hydroxyproline (HOP) are markers of bone cell activity. The kinetics of these markers and the analysis of their variations could be related to the osteoarticular status (OAS) of young horses. The growth of Thoroughbreds, French Trotters and Selle Français horses was followed up to 18 months. Blood samples were taken regularly to measure OC, HOP and BAP by standardized techniques. The OAS was evaluated by radiographic examination of the limbs. Based on radiographic findings, two groups of horses were investigated, with no lesions or severely affected. Analysis of variance was used to detect the effects of age and breed, and OAS on parameters. The logarithmic model was used to determine the kinetics of the markers. A rapid decrease in marker concentrations with age and differences between breed was observed. At birth, BAP, OC and HOP concentrations were significantly higher in normal horses (1910 UI l− 1, 192 ng ml− 1 and 35 mg l− 1, respectively) than in horses with severe lesions (1620 UI l− 1, 149 ng ml− 1 and 24 mg l− 1, respectively). During the first 6 months, OC, HOP and BAP remained lower in severely affected horses.

Lameness manifests itself during the movement of the animal or at rest, indicating a structural or functional disturbance in one or more limbs. Videographic analyses allow the qualitative and quantitative investigation of the movement, reducing the subjectivity of evaluations. The objective was to record the alterations in the movement of the head and limbs of horses in a lame and non-lame condition. Video cameras (60 Hz) and computational methods were used. Six Purebred Arabian colts were filmed on a treadmill, at walk and at trot, before and after induction of lameness. Lameness was induced in the left forelimb utilizing a transient lameness model. Markers were placed on the zygomatic process of the temporal bone, spiny process of the sixth thoracic and first lumbar vertebrae and on the proximal phalange. Nine strides were analysed. At walk and at trot, the animals demonstrated two vertical head movements per stride, while after induction of lameness only one head movement was observed per stride, where this movement was of greater amplitude. The head was shown to be in a more elevated position when the lame limb made first contact with the treadmill belt, which was not observed in the case of the healthy limbs. Only with trotting did the lame animals manifest a prolonged duration of the stance phase for all limbs. The lame animals had a longer support time, lifted the non-lame limbs and showed a shorter stride. Videographic analyses offered details of the alterations in the movement of horses, which are important in the diagnosis of lameness.

The aim of this study was to determine the heart rate (HR) and work variables of working cattle dogs during actual mustering exercise using a global positioning satellite (GPS) tracking unit‡ with an integrated HR monitor§. The GPS units allowed tracking of seven different Collie and Kelpie working cattle dogs over a total of ten sessions while employed in their usual role of mustering cattle in three locations in Queensland, Australia. Speed, distance and HR data were collected from the dogs during mustering in a variety of working situations. The working dogs covered distances between 13.3 and 30.2 km during mustering sessions ranging from 1 h 59 min to 4 h 24 min at working speeds of up to 43.7 km h− 1. Working temperatures ranged from 29 to 38°C. HR during working exercise ranged between 120 and 237 bpm and was above 180 bpm for 51–68% of the duration of work sessions. There was a positive linear relationship between speed and HR until HRmax (speed 26.0 km h− 1, 233 ± 4.2 bpm), then HR plateaued (R2 = 97.14%, P < 0.001). This study has documented the type of work done by cattle dogs and has shown that GPS devices and HR monitors can be utilized in field conditions to assess the exercise physiology of dogs.

Reasons for performing the study: In human exercise physiology, the current gold standard for evaluating aerobic capacity is the measurement of oxygen consumption (VO2) and maximal oxygen uptake (VO2max). The evaluation of VO2 in horses is performed in some laboratories equipped with a treadmill but has only been exceptionally reported in field conditions because of the lack of adapted equipment. Objectives: The aim of this study was (1) to assess the feasibility of VO2 measurement on the track using a recently validated portable breath-by-breath gas analyser system adapted to horses (Cosmed K4b2® and Equimask®), (2) to compare these results with those obtained during a treadmill exercise test and (3) to study correlations between VO2 and physiological parameters usually measured in field condition such as heart rate (HR), lactataemia (LA) and the speed at which HR equals 200 beats per minute (bpm) (V200) or LA 4 mmol l− 1 (VLA4). Methods: Five healthy Standardbred trotters in training were submitted to two stepwise incremental exercise tests, one driven on the racetrack and the other on a high-speed treadmill with a 4% incline. Speed (v), HR, ventilatory parameters and VO2 were continuously recorded throughout the duration of the tests and LA was evaluated after each step. Results: All horses completed the test satisfactorily after an initial acclimatization to the mask. There were marked individual differences in ventilatory strategy, and breathing frequency (Rf) at the higher levels of exercise was noticeably low. The VCO2 measurements were incoherent. There were no significant differences between track and treadmill maximal data obtained during the last step [VO2peak (track: 139.9 ± 8.9 ml kg− 1 min− 1; treadmill: 139.9 ± 13.4 ml kg− 1 min− 1), LAmax (track: 6.5 ± 1.6 mmol l− 1; treadmill: 7.3 ± 3.0 mmol l− 1), HRmax (track: 229 ± 6.2 bpm; treadmill: 222 ± 13 bpm)], although the maximal speed required to reach similar workloads was significantly higher on the track (11.9 ± 0.6 m s− 1vs. 9.7 ± 0.4 m s− 1). The correlation between VO2 and HR (r = 0.87; P < 0.001) and VO2 and LA (r = 0.75; P < 0.0001) during both tests was good but no correlation was found between VO2peak and HRmax, LAmax, V200 or VLA4. Conclusions: This is the first report of a practical portable system to measure VO2 and ventilation continuously during high-speed field exercise tests. However, current mask design markedly influences ventilation and could have prohibited the attainment of VO2max. Furthermore, consistent VCO2 measurements should be implemented by the manufacturers. Potential relevance: Continuous breath-by-breath ventilation and VO2 measurements can be recorded in horses in the field at submaximal levels. With necessary adaptations to the system entailed, this study opens new perspectives in the analysis of physiological and metabolic mechanisms of exercise in the equine species in genuine track conditions.