Abstract: REASONS FOR PERFORMING STUDY: In many equestrian activities a specific position of head and/or neck is required that is dissimilar to the natural position. There is controversy about the effects of these positions on locomotion pattern, but few quantitative data are available. OBJECTIVES: To quantify the effects of 5 different head and neck positions on thoracolumbar kinematics of the horse. METHODS: Kinematics of 7 high level dressage horses were measured walking and trotting on an instrumented treadmill with the head and neck in the following positions: HNP2 = neck raised, bridge of the nose in front of the vertical; HNP3 = as HNP2 with bridge of the nose behind the vertical; HNP4 = head and neck lowered, nose behind the vertical; HNP5 = head and neck in extreme high position; HNP6 = head and neck forward and downward. HNP1 was a speed-matched control (head and neck unrestrained). RESULTS: The head and neck positions affected only the flexion-extension motion. The positions in which the neck was extended (HNP2, 3, 5) increased extension in the anterior thoracic region, but increased flexion in the posterior thoracic and lumbar region. For HNP4 the pattern was the opposite. Positions 2, 3 and 5 reduced the flexion-extension range of motion (ROM) while HNP4 increased it. HNP5 was the only position that negatively affected intravertebral pattern symmetry and reduced hindlimb protraction. The stride length was significantly reduced at walk in positions 2, 3, 4 and 5. CONCLUSIONS: There is a significant influence of head/neck position on back kinematics. Elevated head and neck induce extension in the thoracic region and flexion in the lumbar region; besides reducing the sagittal range of motion. Lowered head and neck produces the opposite. A very high position of the head and neck seems to disturb normal kinematics. POTENTIAL RELEVANCE: This study provides quantitative data on the effect of head/neck positions on thoracolumbar motion and may help in discussions on the ethical acceptability of some training methods.

Abstract: Horses involved in road traffic accidents (RTAs) are commonly presented to veterinarians with varying types of injuries. The aim
of this study was describe the pattern and severity of traffic accident-related injuries in horses in a single hospital population. Medical
records of horses either hit by a motorized vehicle or involved in RTAs whilst being transported from 1993 to 2015 were retrospectively
reviewed and the following data was extracted: Signalement, hospitalisation time, month in which the accident happened, cause of the
accident, place of the accident and type of vehicle hitting the horse. Further the different body sites injured (head, neck, breast, fore limb,
abdomen, back and spine, pelvis and ileosacral region, hind limb, tail and genital region), the type of injury (wounds, musculoskeletal
lesions and internal lesions) and the presence of neurological signs were retrieved from the medical records. 34 horses hit by motorized
vehicles and 13 horses involved in RTAs whilst being transported were included in the study. Most of the accidents where horses were hit
by motorized vehicles occurred during December (14.7%) and October (14.7%), horses were most commonly hit by cars (85.3%) and the
majority of accidents occurred on main roads (26.5%). In 29.4% of the cases, horses had escaped from their paddock and then collided
with a motorized vehicle. Most of the accidents with horses involved in RTAs whilst being transported occurred during April (30.8%) and
June (23.1%). In 76.9% of the cases the accident happened on a freeway. In the horses hit by motorized vehicles the proximal hind limbs
were the body site most commonly affected (44.1%), followed by the proximal front limbs (38.2%) and the head (32.4%). When horses
were involved in RTAs whilst being transported the proximal fore limbs (61.5%), the proximal hind limbs (53.8%) and the distal hind limbs,
back and head (38.5% each) were the most common injured body sites. Wounds were the most common type of injury in both groups
(85.3% hit by motorized vehicle, 76.9% transported ones). In horses hit by a motorized vehicle 35.3% suffered from fractures, in 20.6%
a synovial structure was involved and in 5.9% a tendon lesion was present. 14.7% suffered from internal lesions and 14.7% showed neurologic
symptoms (40% peripheral, 60% central neurologic deficits). On the other hand, in horses involved in a RTA whilst being transported
30.8% suffered from fractures. There were no synovial structures injured and no tendon injuries were present. Furthermore there were
no internal lesions present and only one horse involved in a RTA showed central neurologic symptoms. Injuries of horses being hit by a
motorized vehicle were more severe than when horses were protected by a trailer and involved in a RTA whilst being transported. The study
has been able to identify the different injury types of traffic accident-related injuries in horses. Awareness of the nature of these injuries is
important, to avoid underestimation of their severity.

Abstract: Ziel der Studie war die Beschreibung der motorischen Lateralität („Schiefe“) gesunder adulter Pferde. Hierzu wurden 14 lahmfreie Pferde (10 Warmblüter, 4 Quarter Horses) auf dem Laufband in Schritt und Trab auf individuelle Abweichungen von der symmetri-schen Bewegung hinsichtlich Abstellung der Hinterhand, Wirbelsäulenform (Biegung), Vor- und Rückführung sowie Belastung von Vorder- und Hintergliedmaßen jeweils simul-tan hochfrequenzkinematographisch und kinetisch mittels resistiver Hufdrucksensoren untersucht. Zusätzlich wurden bevorzugte Abstellung und Biegung sowie Galopppräfe-renz klinisch bzw. reiterlich beurteilt, das Vorliegen einer Weideschrittpräferenz unter-sucht und Freilaufversuche (bevorzugte Abbiegerichtung, Ausweichrichtung um ein Hin-dernis, Galoppräferenz) durchgeführt. Keines der Pferde zeigte Symmetrie über alle Merkmale; zwar wurde bei jedem Merkmal für einzelne Probanden Symmetrie festgestellt, mit Ausnahme des Galopp-Freilaufver-suchs trat Asymmetrie jedoch häufiger auf. 12 Probanden zeigten in der Bewegungsana-lyse eine signifikante seitliche Abstellung (8x rechts (R), 4x links (L), mittlere seitliche Abweichung im Schritt 1,22°±1,09°, im Trab 1,05°±1,03°), 10 eine bevorzugte Biegung (9x L, 1x R), 13 signifikante Asymmetrien der Gliedmaßenvor- bzw. -rückführung und 12 eine signifikante asymmetrische Gliedmaßenbelastung für die normalisierte Spitzenkraft (PFN, peak force) bzw. den Impuls der Belastung (IN) an mindestens einem Beinpaar (alle Merkmale individuell wiederholbar). Linksabgestellte Pferde führten in beiden Gang-arten das rechte Hinterbein signifikant weiter zurück als nach rechts abgestellte Pferde, die tendenziell eher das linke Hinterbein weiter zurückführten. – Die auf dem Laufband festgestellten Asymmetrien traten in beiden Gangarten auf, aber nicht immer überein-stimmend, wobei die Richtung der bevorzugten Abstellung und ebenso der bevorzugten Biegung beim einzelnen Pferd in Schritt und Trab nie gegensätzlich waren. Jeder dieser beiden Parameter wurde daher für das einzelne Pferd über beide Gangarten zusammen-gefasst. Die Richtung von Abstellung und Biegung waren voneinander unabhängig, so-dass die Bewegungsmuster Abstellung ohne Biegung, Biegung ohne Abstellung, Abstel-lung mit Biegung in Laufrichtung (Travers) sowie Abstellung mit Biegung entgegen der Laufrichtung (Schulterherein) vorkamen. Kein Pferd war in beiden Merkmalen symmet-risch; für manche Pferde war neben der einfachen Biegung auch eine S-Form der Wir-belsäule signifikant. Die Belastungssymmetrie der Gliedmaßen war in beiden Gangarten von der Abstellung und der Biegung unabhängig, es gab aber Hinweise auf Zusammen-hänge zwischen bestimmten Kombinationen von Abstellung und Biegung einerseits und der Existenz einer Belastungsasymmetrie der Vorderbeine im Trab andererseits (unge-bogen mit Abstellung laufende und im Schulterherein laufende Pferde belasteten i.d.R. asymmetrisch).
8 Pferde wiesen eine signifikante Weideschrittpräferenz auf (5x L, 3x R), die bei ebenso vorhandener seitlicher Abstellung signifkant häufiger auf der der Abstellung abgewandten Seite auftrat. Sie wies keinen Zusammenhang mit der Rückführung der Hinterbeine im Schritt oder im Trab auf. Das Auftreten einer Weideschrittpräferenz war signifikant vom durch Abstellung und Biegung bestimmten Bewegungsmuster abhängig (Auftreten bei Abstellung ohne Biegung und bei Schulterherein, nicht bei Travers oder Biegung ohne Abstellung). Zudem zeigt die Präferenz der Pferde im Weideschritt eine starke Überein-stimmung mit der Belastungssymmetrie der Vorderbeine im Trab (bevorzugt vorgestelltes Bein wird mehr belastet (IN); symmetrische Belastung bei fehlender Präferenz). Im Hindernisversuch hatten 12 von 13 getesteten Probanden eine signifikant bevorzugte Ausweichrichtung (5x L, 7x R); diese war unabhängig von der gemessenen Wirbelsäulenform, lag aber bei Pferden mit seitlicher Abstellung überwiegend auf der Seite der gemessenen Abstellung. Im Abbiegeversuch zeigten 6 von 12 getesteten Probanden eine signifikant bevorzugte Abbiegerichtung (3x L, 3x R), diese war weder von der Abstellungsrichtung noch von der Wirbelsäulenform, der Weideschrittpräferenz oder der Belastungssymmetrie der Vorderbeine im Trab abhängig. Die meisten Pferde zeigten im Freilauf keine signifikante Galopppräferenz (2x L, 11x gerade (N), 1x R), wogegen reiterlich bei den meisten Pferden eine Präferenz festgestellt wurde; beide Beurteilungen stimmten ebenso wie die Beurteilungen verschiedener Reiter nicht miteinander überein. Die gemessene Abstellungsrichtung ließ sich durch visuelle Beobachtung mit hoher Si-cherheit vorhersagen. Die bevorzugte Wirbelsäulenform stimmte nicht mit der reiterlich oder an der Longe festgestellten Biegung überein, wohl aber mit der Seite, auf die die Mähne fällt. Die vorliegende Studie weist nach, dass individuell stabile motorische Lateralität, weitge-hend bestehend aus den den Merkmalen der reiterlich postulierten „Schiefe“, bei gesun-den Pferden in symmetrischen Gangarten besteht und dass zwischen bestimmten Merkmalen vorhersagbare Zusammenhänge bestehen. Daraus ergeben sich wertvolle Schlussfolgerungen für das reiterliche Geraderichten des Pferdes, für das in Übereinstimmung mit der Reitliteratur insbesondere die Lektion Schulterherein geeignet erscheint. Es ist gelungen, für die wesentlichen Merkmale Abstellung, Biegung und Belastungssymmetrie der Vordergliedmaßen im Trab klinische Tests aufzuzeigen, die mit hoher Sicher-heit die Ergebnisse der Bewegungsanalyse vorhersagen können, wobei Rückschlüsse auf weitere asymmetrische Merkmale möglich sind. Die reiterliche Beurteilung von bevor-zugter Biegung und Galopppräferenz scheint jedoch von weiteren Faktoren außer dem Pferd selbst abhängig zu sein und stimmt häufig nicht mit den messbaren Parametern überein. – In dieser Studie wird erstmals eine wissenschaftlich überprüfte und klinisch anwendbare Methode zur umfassenden Analyse der motorischen Lateralität im Sinne der „Schiefe“ eines Pferdes beschrieben.
Summary -“Crookedness“ in the Horse: Symmetry of Motion and Hoof Loading
The purpose of this study was description of motor laterality (in terms of “crookedness“) of sound adult horses. 14 non-lame horses (10 Warmblood horses, 4 Quarter Horses) were examined walking and trotting on a treadmill for individual motion asymmetry concerning keeping the hindlimbs at an angle (hindlimbs not tracking the frontlimbs, “hindquarter angle”), lateroflexion, pro- and retraction of the limbs as well as loading of front- and hindlimbs. High-speed-kinematography and resistive pressure sensors were used simultanously. The horses were also ridden to evaluate preferred lateroflexion and preferred lead in canter. Moving at an angle towards a preferred side was assessed visually. Laterality of grazing stance was tested, as well as preferred turning direction, obstacle avoidance direction and preferred lead in canter while moving unrestrained in an arena. None of the horses moved symetrically over all traits; although there were symmetrical traits with individual horses, asymmetry was more commen (except for the unrestrained preferred lead test). On the treadmill, 12 horses moved with their hindquarters significantly at a angle (8x right (R), 4x left (L), mean lateral angle 1,22°±1,09° at a walk and 1,05°±1,03° at a trot), 10 showed laterality for lateroflexion (9x L, 1x R), 13 had significant asymmetries for protraction and/ or retraction and 12 for loading of contralateral limbs concerning normalized peak force (PFN) and impulse (IN), respectively, of at least one pair of limbs (all with good repeatibility). Horses keeping their hindquarters to the left showed significantly larger retraction of the right hindlimb compared to horses keeping their hindquarters to the right, who tended to further retract the left hindlimb. – Asymmetries found on the treadmill occurred in both gaits but were not always the same in both gaits, though the direction of the hindquarter angle as well as that of the preferred lateroflexion never contradicted each other within the same individual. Therefore, a specific laterality direction of hindquarter angle and lateroflexion could be assigned to each horse. The direction of preferred hindquarter angle and lateroflexion, respectively, were independent of each other so that the movement patterns “hindquarter angle without lateroflexion”, “lateroflexion without hindquarter angle”, “hindquarter angle with lateroflexion to the same side” (hindquarter-in/ travers) and “hindquarter angle with lateroflexion to opposite sides” (shoulder-in) could be found; no horse moved symmetrical for both traits. The lateroflexion of some horses could even be regarded as a double bend. At both gaits, symmetry of limb loading was independent of hindquarter angle as well as lateroflexion, taken seperately; still, there seems to be a relation between certain combinations of hindquarter angle and lateroflexion, on the one side, and the existence or absence of asymmetric loading of the frontlimbs in trot (horses moving with hindquarter angle, but without lateroflexion, and horses moving in shoulder-in mostly had asymmetric frontlimb loading).
238 7. Summary8 horses displayed laterality for a grazing stance (5x L, 3x R); their hindquarter angle, if they showed one, was significantly more often on the opposite side of their advanced frontleg while grazing. The direction of the grazing stance was independent of hindlimb retraction symmetry in either gait. Occurrence of grazing stance laterality significantly depended on the movement pattern consisting of hindquarter angle and lateroflexion (horses moving with a hindquarter angle, but without lateroflexion, and horses moving in shoulder-in mostly showed grazing stance laterality, while horses moving with lateroflexion, but without a hindquarter angle, and horses moving in hindquarter-in did not). Also, grazing stance laterality was highly predictive of the symmetry of frontlimb loading at trot (advanced frontleg has significantly higher impulse (IN) at trot; horses without grazing stance laterality showed symmetrical impulse). 12 of 13 horses displayed laterality for obstacle avoidance direction (5x L, 7x R) that was independent of the individually preferred lateroflexion but if the horses showed a hindquarter angle it was usually to the same side. 6 of 12 horses showed laterality for turning direction (3x L, 3x R) that had no relation to laterality of either hindquarter angle, lateroflexion, grazing stance or frontlimb loading symmetry at trot. Most horses had no significant lead preference in the unrestrained canter test (2x L, 11x no preference (N), 1x R) even though riders assigned a lead preference to most horses; both ratings did not match, as well as the rating between two different riders did not match. The (measured) direction of hindquarter angle was highly predictable by visual asessment. Preferred (measured) lateroflexion did not match the direction of lateroflexion assigned by either rider or on the long line; it was in agreement with the mane side of the horse, though. This study proves that individual and stable motor laterality exists in sound horses in symmetrical gaits, mostly consisting of the traits that are hypothesized as “crookedness” in riding literature. It also shows that predictible relationships exist between certain traits thereof. This knowledge is valuable since it has implications for the training of riding horses for straightness, wherefore especially riding shoulder-in should be helpful. Relatively easy clinical tests could successfully be found that allow well predicting main features of individual horses ́ motor laterality like hindquarter angle, lateroflexion and frontlimb loading symmetry at trot as measured on the treadmill. Some conclusions can also be drawn for other asymmetrical traits. The asessment of preferred lateroflexion and canter lead performed by riders, though, seems to also underlie other influences than the horse itself and failed to be a predictor of the measured traits. – For the first time, a scientifically proven and clinically applicable method of asessing a horses motor laterality in terms of “crookedness” is presented.