Kinetics and kinematics of the tölt: effects of rider interaction and shoeing manipulations

Introduction . Compared to most equine horse breeds which are able to walk, trot and canter /gallop, the gait repertoire of the Icelandic horses additionally includes the lateral gait tölt and frequently also the pace. With respect to the tölt gait, special shoeing, saddling and riding techniques have been developed for Icelandic horses in order to enhance its expressiveness and regularity. Toes are left unnaturally long and heavy shoes and paddings, as well as weighted boots are used to enforce the individual gait predisposition. For the same reason, the rider is placed more caudally to the horse's centre of mass as compared to other riding techniques. The biomechanical impact of these methods on the health of the locomotor system has so far never been subject of systematic research. Objectives . The aims of the presented study are (1) to describe the kinetic and kinematic characteristics of the tölt performed on a treadmill, (2) to understand the mechanical consequences of shoeing manipulation (long hooves, weighted boots) on the loading and protraction movement of the limbs, as well as (3) to study the pressure distribution and effects on the gait pattern of 3 different saddle types used for riding Icelandic horses. Materials and methods . Gait analysis was carried out in 13 Icelandic horses at walk and at slow and medium tölting and trotting speeds on a high-speed treadmill instrumented for measuring vertical ground reaction forces as well as temporal and spatial gait variables. Kinematic data of horse, rider and saddle were measured simultaneously. Gait analysis was first carried out with high, long hooves (SH) without and in combination with weighted boots (ad aim (2)). Afterwards, horses were re-shod according to current horseshoeing standards (SN) and gait analysis was repeated (ad aims (1) and (2)). In a second trial, horses were additionally equipped with a pressure sensitive saddle mat and were ridden with a dressage-like saddle (SDres), an Icelandic saddle (Slcel) and a saddle cushion (SCush) in the standard saddle position (ad aim 3). Results and conclusions . Compared to trot at the same speed, tölting horses had a higher stride rate and lower stride impulses. At the tölt loading of the forelimbs was increased in form of higher peak vertical forces (Fzpeak) due to shorter relative stance durations (StDrel). Conversely, in the hindlimbs, longer StDrel resulted in lower Fzpeak. Despite the higher head-neck position at tölt, there was no measurable shift in weight to the hindlimbs. Footfall rhythm was in most horses laterally coupled at the tölt and frequently had a slight fourbeat and a very short suspension phase at trot; underlining the fact that performance of correct gaits in Icelandic horses needs special training. Gait performance as it is currently judged in competition could be improved using a shoeing with SH, resulting in a 21 ± 5 mm longer dorsal hoof wall, but also a weight gain of 273 ± 50 g at the distal limb due to heavier shoeing material. Compared to SN, SH led to a lower stride rate, a longer stride length and a higher, but not wider, forelimb protraction arc, which were also positively associated with speed. At the tölt, the footfall rhythm showed less tendency to lateral couplets and at the trot, the suspension phase was longer. However, on the long term, SH may have negative implications for the health of the palmar structures of the distal foot by increased limb impulses, higher torques at breakover (up to 20%); as well as peak vertical forces at faster speeds. Compared to the shoeing style, the saddle type had less influence on limb forces or movements. The slight weight shift to the rear with SCush and Slcel may be explained by the more caudal position of the rider relative to the horse's back. With SCush, pressure was highest under the cranial part of the saddle, whereas the saddles with trees had more pressure under the caudal area

Adaptation strategies of horses with induced forelimb lameness walking on a treadmill

Background There is a paucity of research describing the gait pattern of lame horses at the walk. Objectives To describe the changes in motion pattern and vertical ground reaction forces (GRFz) in horses with induced forelimb lameness at the walk and compare those changes with the changes observed at the trot. Study design Experimental study. Methods In 10 clinically sound Warmblood horses, moderate forelimb lameness was induced using a sole pressure model followed by trot and walk on a treadmill. Kinematic data were collected using 3D optical motion capture (OMC), and GRFz by an instrumented treadmill. Mixed models were used to compare sound baseline versus forelimb lameness (significance was set atP < .05). Results Lameness induction significantly reduced peak GRFz on the second force peak, and vertical impulse in the lame limb. Stride and stance duration in all limbs were reduced. Lameness significantly affected the vertical movement symmetry of the head and withers. Maximum limb retraction angle, fetlock extension and protraction speed were reduced in the lame limb. Body centre of mass (COM) translation was reduced in the side-to-side direction and increased in the vertical and fore-aft directions. Several compensatory kinetic and kinematic changes were observed in the nonlame limbs. The observed changes in both kinetics and kinematics were generally smaller at walk with fewer variables being affected, compared to the trot. Main limitations Only one degree and type of orthopaedic pain (sole pressure) was studied. Conclusions Compensatory strategies of forelimb lameness at the walk include alteration of several kinetic and kinematic parameters and have some specific patterns and inter-individual differences that are not seen at the trot. However, much like at the trot, head movement and forelimb vertical force symmetry seem to be the most useful parameters to detect forelimb lameness at walk

Evaluation of skin sensitivity after shock wave treatment in horses

Ziel der Studie-Untersuchung der Wirkung von Stosswellentherapie auf die kutane Nervenfunktion, im Vergleich mit der Wirkung von Lokalanästhesie und Sedation. Probanden-18 klinisch gesunde Warmblutpferde. Methode- Die Pferde wurden randomisiert in 3 Gruppen eingeteilt und mit einer jeweils unterschiedlichen Anzahl und verschiedenen Arten von Stosswellen (Extrakorporale fokussierte [ESWT] oder Radiale Stosswellentherapie [RPWT]) behandelt. Die Pferde wurden mit Xylazin und Levomethadon sediert. Die Stosswellen wurden auf Höhe des proximalen Sesambeins eines Vorderbeins direkt auf den Nervus palmaris digitalis lateralis appliziert. Sowohl vor, als auch 5 Minuten nach Sedation; sowie 4, 24, und 48 Stunden nach ESWT oder RPWT wurde die Hautsensibilität mittels elektrischer Stimulation am Kronrand ermittelt. Am kontralateralen Vorderbein wurde die Sensibilität vor und 10 Minuten nach einer Mittleren Palmaranästhesie (MPA) getestet. Ergebnisse-Unabhängig von der angewandten Therapiemethode konnte keine signifikante Veränderung der Hautsensibilität nach Stosswellentherapie festgestellt werden. Die durchschnittliche Reaktionsschwelle nach Sedation lag mehr als doppelt so hoch wie davor. Nach der MPA war innerhalb des Stimulationsbereiches bei keinem Pferd eine Reaktion auszulösen. Schlussfolgerung und klinische Bedeutung-ESWT oder RPWT des N. palmaris digitalis lateralis hatte keine Auswirkung auf die Wahrnehmung elektrischer Stimuli distal des Behandlungsgebietes. Der analgetische Effekt nach Sedation war deutlich, zeigte jedoch eine starke individuelle Variation. Objective-Evaluate effects of shock wave treatment on the function of cutaneous nerves in comparison with the effects of local nerve block and sedation. Animals-18 clinically sound Warmbloods. Procedure-Horses were randomly allocated to 3 groups and received different amounts and types of shock waves (extracorporeal shock wave treatment [ESWT] or radial pressure wave treatment [RPWT]). Horses were sedated with xylazine and levomethadone. Shock waves were applied to the lateral palmar digital nerve at the level of the proximal sesamoid bones on 1 forelimb. Skin sensitivity was evaluated by means of an electrical stimulus at the coronary band before and 5 minutes after sedation, and at 4, 24, and 48 hours after application of ESWT or RPWT. On the contralateral forelimb, skin sensitivity was tested before and 10 minutes after an abaxial sesamoid nerve block. Results-There were no significant changes in skin sensitivity, regardless of the shock wave method applied. Mean reaction thresholds after sedation were more than twice the baseline thresholds. After the abaxial sesamoid block, no reaction was recorded in any of the horses. Conclusions and Clinical Relevance-Application of ESWT or RPWT to the palmar digital nerve had no effect on cutaneous sensation distal to the treated region for at least 2 days after application. The analgesic effect of sedation on reaction to electrical stimuli was distinct but varied among horses

Passive dynamics explain quadrupedal walking, trotting, and tölting

This paper presents a simplistic passive dynamic model that is able to create realistic quadrupedal walking, tölting, and trotting motions. The model is inspired by the bipedal spring loaded inverted pendulum (SLIP) model and consists of a distributed mass on four massless legs. Each of the legs is either in ground contact, retracted for swing, or is ready for touch down with a predefined angle of attack. Different gaits, that is, periodic motions differing in interlimb coordination patterns, are generated by choosing different initial model states. Contact patterns and ground reaction forces (GRFs) evolve solely from these initial conditions. By identifying appropriate system parameters in an optimization framework, the model is able to closely match experimentally recorded vertical GRFs of walking and trotting of Warmblood horses, and of tölting of Icelandic horses. In a detailed study, we investigated the sensitivity of the obtained solutions with respect to all states and parameters and quantified the improvement in fitting GRF by including an additional head and neck segment. Our work suggests that quadrupedal gaits are merely different dynamic modes of the same structural system and that we can interpret different gaits as different nonlinear elastic oscillations that propel an animal forward

Auswirkungen der Fütterung bei Endurancepferden auf Blutparameter des Energiestoffwechsels: Vergleich von Theorie und Praxis

Ziel der vorliegenden Untersuchung ist es, die praktische Fütterung von Endurancepferden zu erfassen und ihre Auswirkungen auf den Energiestoffwechsel anhand von bestimmten Parametern zu ermitteln. So gilt insbesondere bei Ausdauerleistungspferden als erwiesen, dass die Rationsgestaltung einen grossen Einfluss darauf hat, ob die Tiere Hochleistungen erbringen können. Zur Datenerfassung wurden die zustimmenden Teilnehmer eines 120 km-Distanzrennens mittels eines Fragebogens zur genauen Futteraufnahme ihrer Pferde am Abend vor dem Wettkampf sowie am Wettkampftag befragt. Den Pferden wurde bei der Voruntersuchung am Abend vor dem Wettkampf sowie in jeder Pause alle ca. 30 km sowie nach der Schlusskontrolle Blut entnommen (Plasma, Serum) und die Parameter Glucose und Laktat (sofort nach der Entnahme), freie Fettsäuren, Triglyceride, Gesamteiweiss (nach Lagerung bei -20° C) und Insulin (nach Lagerung bei - 80° C) untersucht wurde. Die bisher bestimmten Werte deuten darauf hin, dass Pferde, die aus unterschiedlichen Gründen aus dem Wettbewerb ausgeschieden sind, niedrigere Blutglucosekonzentrationen hatten als Pferde, welche die tierärztlichen Kontrollen bestanden. Beim Laktat und den übrigen erfassten Parametern zeigten sich keine Unterschiede. Es wird vermutet, dass die Art und Menge der Kraftfuttergaben am Morgen vor dem Wettkampf und innerhalb der Pausen einen direkten Einfluss auf die Futteraufnahme der Pferde sowie die Blutglucose- und vermutlich auch Insulinkonzentrationen haben könnte

Comparison of limb loading and movement of Icelandic horses while tölting and trotting at equal speeds

OBJECTIVE: To compare gait mechanics and limb loading in Icelandic horses tölting and trotting at equal speeds and estimate their impact on orthopedic health. ANIMALS: 12 orthopedically normal Icelandic horses. PROCEDURES: Kinetic and kinematic gait variables were simultaneously recorded as each horse was ridden at a tölt and trot on an instrumented treadmill at 3.4 m/s and 3.9 m/s. Differences between gaits were tested via 1-factor repeated-measures ANOVA. RESULTS: Horses had a higher stride rate and lower stride impulses at a tölt than at a trot. For forelimbs at a tölt, shorter relative stance duration resulted in higher peak vertical force (Fzpeak). Conversely, for hind limbs, longer relative stance duration resulted in lower Fzpeak. The higher head-neck position at a tölt versus trot caused no weight shift to the hind limbs, but a higher forehoof flight arc and lower proretraction movement were identified. Stance durations for forelimbs were briefer than for hind limbs at a tölt, and the inverse was observed at a trot. Minimal height of the horse's trunk at the point of Fzpeak of the respective limb suggested a spring-like mechanism for all limbs at a tölt. Hind limb measurements revealed no evidence of increased collection. Stride-to-stride limb timing varied more at a tölt than at a trot. At a trot, horses had brief or no suspension phases and a slightly 4-beated footfall rhythm was common. Post hoc energetic estimations revealed that tölting at the measured speeds was less advantageous than trotting. CONCLUSIONS AND CLINICAL RELEVANCE: High forelimb action in Icelandic horses and higher head-neck position at a tölt were associated with more restricted limb proretraction, higher Fzpeak, and faster force onset than at a trot. The impact of these differences on orthopedic health needs to be investigated more in detail

Kinetische Auswertung des Schrittes von Jungrindern und Kühen auf einem instrumentierten Laufband

Gegenstand und Ziel: Daten über die Schrittcharakteristika oder die Bodenreaktionskräfte von Milchkühen gewinnen zunehmend an Bedeutung. Deshalb wurden kinetische Variablen von gesunden Jungrindern und Kühen, die auf einem Laufband im Schritt gingen, dokumentiert und ausgewertet. Material und Methodik: Neun Jungrinder und 10 Kühe wurden an das Gehen auf dem Laufband gewöhnt. Mit dem mit Kraftaufnehmern versehenen Laufband konnten Bodenreaktionskräfte, Schrittlängen und zeitliche Variablen der Stütz- und Hangbeinphasen für alle Gliedmaßen gleichzeitig aufgezeichnet werden. Ergebnisse: Die Kühe gingen bei einer durchschnittlichen Geschwindigkeit von 1,2 ± 0,05 m/s (Mittelwert ± Standardabweichung) mit einer Doppelschrittkadenz von 43,0 ± 1,9/min und einer Doppelschrittlänge von 1,68 ± 0,1 m. Bei den Jungrindern ergaben sich für die entsprechenden Parameter 1,3 ± 0,04 m/s, 53,7 ± 2,2/min und 1,49 ± 0,05 m. Der zeitliche Anteil der Stützbeinphase relativ zur Dauer eines Doppelschritts war bei Kühen an den Schultergliedmaßen (67%) signifikant größer als an den Beckengliedmaßen (64%). Die Kraft-Zeit-Kurven aller Gliedmaßen waren zweigipflig mit einem Gipfel (FP1) kurz nach dem Auffußen und einem Gipfel (FP2) in der Abstoßphase. Die vertikale Bodenreaktionskraft war an den Beckengliedmaßen bei FP1 am höchsten, an den Schultergliedmaßen bei FP2. Das zwischen den beiden Gipfeln befindliche Minimum lag mit 45–49% der Stützbeinphase kurz vor deren Mitte. Der Anteil beider Schultergliedmaßen am Gesamtimpuls betrug 53,7% bei Kühen und 55,0% bei Jungrindern. Die Lage des Körperschwerpunkts variierte während der einzelnen Bewegungsphasen, war jedoch immer mehr zu den Schultergliedmaßen hin lokalisiert. Schlussfolgerungen: Gesunde Kühe und Jungrinder zeigten einen symmetrischen Gang mit minimalen intraindividuellen Abweichungen. Die Hinterbeine wurden vorwiegend beim Auffußen, die Vorderbeine beim Abstoßen vermehrt belastet. Die Vorderbeine hatten einen größeren Anteil am Gesamtimpuls. Die Untersuchung liefert kinetische Daten für die Ganganalyse von gesunden Kühen und Jungrindern, die bei der automatisierten Erkennung lahmer Rinder nützlich sein können

Effects of shoeing on limb movement and ground reaction forces in Icelandic horses at walk, tölt and trot

Tölt is a symmetric four-beat gait with a speed range extending into that of trot and canter. Specific shoeing methods, such as unnaturally high and long hooves, are used to enforce individual gait predisposition. The aim of this study was to assess the consequences of this shoeing style on loading and movement of the limbs at walk, tölt and trot, and at different velocities. Simultaneous kinetic and kinematic gait analysis was carried out at walk (1.4 m/s) and at two tölting and trotting speeds (3.3 m/s and 3.9 m/s) on an instrumented treadmill. Thirteen sound Icelandic horses were first measured with high, long front hooves (SH) and, one week later, after trimming the hooves according to standard shoeing principles (SN). Comparing SH with SN, front hooves had 21 ± 5 mm longer dorsal hoof walls and the shoeing material per hoof was 273 ± 50 g heavier. In all three gaits, gait quality, as it is currently judged, was improved with SH due to a lower stride rate, a longer stride length and a higher, but not wider, forelimb protraction arc, which were also positively associated with speed. Forelimb-hind limb balance remained unchanged, but limb impulses were higher. Apart from an increase of ⩽ 2.2% in the forelimbs at the faster speed of both tölt and trot, SH had little influence on vertical peak forces