Much controversy exists among riders, and in particular among those practicing dressage, regarding what can be considered an “appropriate” Head-Neck-Position (HNP). The objective was to assess the prevalence of different HNPs in the field, the behavioural reactions of horses during warm-up and competition rides in relation to HNP and the relation between HNP and marks achieved in the competition. Horses (n = 171) were selected during dressage competitions according to their HNP (3 categories based on the degree of flexion), and their behaviour was recorded during 3 minutes each of riding in the warm-up area and in the competition. Scans were carried out on an additional 355 horses every 15 minutes to determine the proportion of each HNP in the warm-up area. Sixty-nine percent of the 355 horses were ridden with their nasal planes behind the vertical in the warm-up area, 19% were ridden at or behind the vertical and only 12% were ridden with their nasal plane in front of the vertical. Horses carrying their nasal plane behind the vertical exhibited significantly (P<0.0001) more conflict behaviours than horses with their nose held in front of the vertical. Horses were commonly presented with a less flexed HNP during competition compared to warm-up (P<0.05). A HNP behind the vertical was penalised with lower marks in the lower (P = 0.0434) but not in the higher (P = 0.9629) competition levels. Horses in higher classes showed more (P = 0.0015) conflict behaviour than those in lower classes. In conclusion, dressage horses are commonly ridden during warm-up for competitions with their nasal plane behind the vertical, and this posture seems to cause significantly more conflict behaviour than HNPs in front of the vertical.

Summary The Knowledge of muscle activity in common head–neck positions (HNPs) is a necessary precondition for making judgements on HNPs. The aim of the study was to record the surface electromyography activities of important muscles of the horse's neck in various HNPs. The electrical activities of the m. splenius, brachiocephalicus and trapezius were recorded on both sides. Five horses, both with and without a rider, were examined in all three gaits on both hands in three different HNPs: a ‘free’ position, a ‘gathered’ (head higher, neck more flexed) position with the noseline in front of the vertical and a ‘hyperflexed’ position. Averages of ten consecutive gait cycles in each HNP were evaluated and compared by standard statistical methods. No difference between ridden and unridden horses could be detected. The m. brachiocephalicus was in the hyperflexed position in all gaits significantly (p < 0.01) more active than in the gathered and free position, which were not significantly different. By contrast, the m. splenius was in the hyperflexed position less active than in the free position (p < 0.02), in which it always showed the highest activity. In walking, the muscle activities in the free and gathered positions deviated significantly (p < 0.01). The m. trapezius was in the hyperflexed posture during walking significantly less active than in the free (p < 0.01) and gathered (p < 0.01) positions with the strongest activities in the free position. Again, the free and gathered positions differed significantly (p < 0.01). In trot, the same pattern occured, although the gathered and hyperflexed positions did not differ significantly. In the canter, the activities of the m. trapezius showed no differences between HNPs. In HNPs with the noseline in front of the vertical, the muscles of the topline (m. splenius, m. trapezius) are activated and trained. In the hyperflexed position, however, a major muscle of the lower topline (m. brachiocephalicus) is activated and trained.

The activity patterns of trunk muscles are commonly neglected, in spite of their importance for maintaining body shape. Analysis of the biomechanics of the trunk under static conditions has led to predictions of the activity patterns. These hypotheses are tested experimentally by surface electromyography (EMG). Five horses, with and without a rider, were examined in the walk, trot and canter. Footfall was synchronised with EMG by an accelerometer. Averages of ten consecutive cycles were calculated and compared by statistical methods. The start and stop times of the muscle activities of 5-10 undisturbed EMG plots were determined and the averages and standard deviations calculated. In walking, muscle activities are minor. Electromyography (EMG) activity was increased in the m. rectus during the three-limb support. When the bending moments assume their greatest values, for example while the horses' mass is accelerated upward (two times earth acceleration) in the diagonal support phases in trot and canter the m. rectus, connecting the sternum with the pubic bone is most active. The m. obl. externus is most active when the torsional and bending moments are greatest during the same support phases, but not bilaterally, because the forces exerted on one side by the (recorded) m. obl. externus are transmitted on the other side by the (not recorded) m. obl. internus. While the hindlegs touch the ground in the trot and canter, ground reaction forces tend to flex the hip joint and the lumbar spine. Therefore, the vertebral column needs to be stabilised by the ipsilateral m. longissimus dorsi, which in fact can be observed. As a whole, our EMG data confirm exactly what has been predicted by theoretical analysis.

Too much rein tension while riding may compromise the welfare of the horse. But who generates the tension on the reins—the horse or the rider? The primary aim of this pilot study was to evaluate the maximum rein tension that horses voluntarily maintain without a rider compared to rein tension with a rider. A secondary aim was to evaluate conflict behaviours in relation to rein tension. Thirteen horses were used, all fitted with customised “Animon” rein tension sensors (25 Hz, up to 600 N range), free-moving with side reins set in dressage competition frame with the noseline on the vertical. Rein tension was measured at the walk, trot, and canter in both directions in a round pen. The same horses were then ridden by their usual riders and completed the same task on a riding ground. Continuous video recordings were obtained to subsequently quantify the occurrence of conflict behaviours. The difference in mean maximum peak of rein tension with and without a rider for each gait was compared using the Wilcoxon Rank Sum test. Without a rider, rein tension was significantly lower (Wilcoxon T = 0, p < 0.01, 7.5 N ± 2.8 N) than with a rider (Wilcoxon T = 0, p < 0.01, 24.0 N ± 12.3 N). Regardless of the different rein tensions in the ridden exercise, all of the horses exhibited approximately the same amount of rein tension in the unridden exercise. The frequency of conflict behaviour was higher with a rider than without (11 ± 14 per minute vs. 2 ± 3 per minute; T = 4, p < 0.01).

Abstract. During their lifetime animals leave many tracks and traces behind, which can provide insights into the animals' behaviour. Single footprints of extant vertebrates are frequently found in sediments all over the world, often arranged into trackways. The study of footprints and trackways lead to interpretations about the mode of locomotion of the trackmaker. Here we show an approach to identify gaits from tracks.A series of experiments with horses was performed to determine whether gaits could be identified on the basis of fossil trackways, e.g. those left behind by sauropod dinosaurs of the Mesozoic era or Tertiary mammals, to unveil their locomotor abilities. The generally valid rules for quadrupedal locomotion were taken into consideration. Symmetrical gaits result in very similar trackways; a further differentiation can be made by application of statistics on step lengths, excursion angles and overstepping.A clear difference exists between the trot and the pace. These rapid, symmetric gaits imply high ground reaction forces (GRF) because of their long phases of aerial suspension at higher speeds. The resulting GRF seem to be too high to be sustained by the limb bones of huge graviportal animals like sauropods. Unfortunately, most of these factors are rarely available in the case of fossil tracks. Likewise, the asymmetrical, springing gaits can be excluded for sauropods because of the enormous GRF. Provided that limb length as well as trunk length can be approximated, and left and right, as well as forefoot and hindfoot imprints can be discriminated, the symmetrical gaits (walk, amble, pace, trot) used when making a trackway can be discerned.