Records |
Author |
Mrosovsky, N.; Shettleworth, S.J. |
Title |
Further studies of the sea-finding mechanism in green turtle hatchlings |
Type |
Journal Article |
Year |
1974 |
Publication |
Behaviour |
Abbreviated Journal |
Behaviour |
Volume |
51 |
Issue |
3-4 |
Pages |
195-208 |
Keywords |
Animals; *Animals, Newborn/physiology; Contact Lenses; Locomotion; *Orientation; Retina/physiology; *Turtles/physiology; Visual Fields; *Visual Perception; Water |
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0005-7959 |
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PMID:4447586 |
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no |
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refbase @ user @ |
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389 |
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Author |
Santamaria, S.; Back, W.; van Weeren, P.R.; Knaap, J.; Barneveld, A. |
Title |
Jumping characteristics of naive foals: lead changes and description of temporal and linear parameters |
Type |
Journal Article |
Year |
2002 |
Publication |
Equine Veterinary Journal. Supplement |
Abbreviated Journal |
Equine Vet J Suppl |
Volume |
|
Issue |
34 |
Pages |
302-307 |
Keywords |
Animals; Animals, Newborn/*physiology; Biomechanics; Female; Forelimb/physiology; Gait/*physiology; Hindlimb/physiology; Horses/*physiology; Locomotion/*physiology; Male |
Abstract |
The selection of foals as future showjumpers remains a subjective process based on qualitative parameters; and hence, frequently suffers from disparity in the criteria used by experts in the field. A detailed biomechanical description of foals while jumping would be most helpful in providing a better basis for the accurate assessment of their future athletic ability. The Qualisys Pro Reflex system was used to capture 3-dimensional kinematics of 41 Dutch Warmblood foals age 6 months free jumping a vertical fence, preceded by a cross pole fence. The left lead was the most preferred lead for both the fore- and hindlimbs, from the landing following the cross poles to the first move-off stride after clearing the vertical fence. The foals displayed a high incidence of rotary gallop during both the jump stride (divided into take-off, jump suspension and landing) and the first move-off stride, while change of lead was frequently observed during jump suspension. At the take-off side of the fence, the trailing forelimb in the last approach stride was placed furthest from the fence, whereas the trailing hindlimb at take-off was placed closest (P<0.05). At the landing side, the trailing forelimb was the closest and the leading hindlimb of the move-off stride 1 was the furthest (P<0.05). The trailing forelimb in the approach stride 1 had a significantly longer stance phase duration than the leading forelimb. At landing, the leading forelimb stance phase lasted longer than that of the trailing forelimb (P<0.05). The hindlimbs did not differ in their stance phase duration at take-off. The height reached by the hooves above the fence top was significantly greater in the hind limbs (P<0.05). In addition, the hindlimbs (97.1 +/- 2.6%) shortened more than the forelimbs (92.6 +/- 5.7%) (P<0.05). It is concluded that the overall jumping technique of foals is similar to that reported in literature for mature horses. If the patterns are consistent throughout the rearing period, the quantitative analysis of the kinematics of free jumping foals may provide a valid quantitative basis for early selection. |
Address |
Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht, The Netherlands |
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PMID:12405705 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3784 |
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Author |
Wennerstrand, J.; Johnston, C.; Roethlisberger-Holm, K.; Erichsen, C.; Eksell, P.; Drevemo, S. |
Title |
Kinematic evaluation of the back in the sport horse with back pain |
Type |
Journal Article |
Year |
2004 |
Publication |
Equine Veterinary Journal |
Abbreviated Journal |
Equine Vet J |
Volume |
36 |
Issue |
8 |
Pages |
707-711 |
Keywords |
Animals; Back/*physiology; Back Pain/diagnosis/physiopathology/*veterinary; Biomechanics; Exercise Test/veterinary; Gait/*physiology; Horse Diseases/diagnosis/*physiopathology; Horses/anatomy & histology/*physiology; Locomotion/physiology; Lumbar Vertebrae/physiology; Range of Motion, Articular; Stress, Mechanical; Thoracic Vertebrae/physiology; Weight-Bearing |
Abstract |
REASONS FOR PERFORMING STUDY: Earlier studies have developed a clinical tool to evaluate objectively the function of the equine back. The ability to differentiate horses with back pain from asymptomatic, fully functioning horses using kinematic measures from this tool has not been evaluated. OBJECTIVES: To compare the kinematics of the back at walk and trot in riding horses with back dysfunction to the same parameters in asymptomatic sport horses. METHODS: The kinematics of the back in 12 horses with impaired performance and back pain were studied at walk and trot on a treadmill. Data were captured for 10 sees at 240 Hz. Range of movement (ROM) and intravertebral pattern symmetry of movement for flexion and extension (FE), lateral bending (LB) and axial rotation (AR) were derived from angular motion pattern data and the results compared to an earlier established database on asymptomatic riding horses. RESULTS: At walk, horses with back dysfunction had a ROM smaller for dorsoventral FE in the caudal thoracic region (T13 = 7.50 degrees, T17 = 7.71 degrees; P<0.05), greater for LB at T13 (8.13 degrees; P<0.001) and smaller for AR of the pelvis (10.97 degrees; P<0.05) compared to asymptomatic horses (FE-T13 = 8.28 degrees, FE-T17 = 8.49 degrees, LB-T13 = 6.34 degrees, AR-pelvis = 12.77 degrees). At trot, dysfunctional horses had a smaller (P<0.05) ROM for FE at the thoracic lumbar junction (T17 = 2.46 degrees, L1 = 2.60 degrees) compared to asymptomatic horses (FE-T17 = 3.07 degrees, FE-L1 = 3.12 degrees). CONCLUSIONS: The objective measurement technique can detect differences between back kinematics in riding horses with signs of back dysfunction and asymptomatic horses. The clinical manifestation of back pain results in diminished flexion/extension movement at or near the thoracic lumbar junction. However, before applying the method more extensively in practice it is necessary to evaluate it further, including measurements of patients whose diagnoses can be confirmed and long-term follow-ups of back patients after treatment. POTENTIAL RELEVANCE: Since the objective measurement technique can detect small movement differences in back kinematics, it should help to clinically describe and, importantly, objectively detect horses with back pain and dysfunction. |
Address |
Department of Anatomy and Physiology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden |
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English |
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0425-1644 |
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Notes |
PMID:15656501 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3656 |
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Author |
Winkelmayr, B.; Peham, C.; Fruhwirth, B.; Licka, T.; Scheidl, M. |
Title |
Evaluation of the force acting on the back of the horse with an English saddle and a side saddle at walk, trot and canter |
Type |
Journal Article |
Year |
2006 |
Publication |
Equine Veterinary Journal. Supplement |
Abbreviated Journal |
Equine Vet J Suppl |
Volume |
|
Issue |
36 |
Pages |
406-410 |
Keywords |
Animals; Back/*physiology; Back Pain/etiology/veterinary; Biomechanics; Exercise Test/veterinary; Female; Gait/physiology; Horse Diseases/etiology; Horses/*physiology; Humans; Locomotion/physiology; Male; Movement/*physiology; *Physical Conditioning, Animal/instrumentation/methods/physiology; *Pressure; Weight-Bearing/*physiology |
Abstract |
REASONS FOR PERFORMING STUDY: Force transmission under an English saddle (ES) at walk, trot and canter is commonly evaluated, but the influence of a side saddle (SS) on the equine back has not been documented. HYPOTHESIS: Force transmission under a SS, with its asymmetric construction, is different from an ES in walk, trot and canter, expressed in maximum overall force (MOF), force in the quarters of the saddle mat, and centre of pressure (COP). The biomechanics of the equine back are different under a SS compared to ES. METHODS: Thirteen horses without clinical signs of back pain ridden in an indoor riding school with both saddles were measured using an electronic saddle sensor pad. Synchronous kinematic measurements were carried out with tracing markers placed along the back in front of (withers, W) and behind the saddle (4th lumbar vertebra, L4). At least 6 motion cycles at walk, trot and canter with both saddles (ES, SS) were measured. Out of the pressure distribution the maximum overall force (MOF) and the location of the centre of pressure (COP) were calculated. RESULTS: Under the SS the centre of pressure was located to the right of the median and slightly caudal compared to the COP under the ES in all gaits. The MOF was significantly different (P<0.01) between saddles. At walk, L4 showed significantly larger (P<0.01) vertical excursions under the ES. Under the SS relative horizontal movement of W was significantly reduced (P<0.01) at trot, and at canter the transversal movement was significantly reduced (P<0.01) . In both trot and canter, no significant differences in the movement of L4 were documented. CONCLUSIONS AND POTENTIAL RELEVANCE: The results demonstrate that the load under a SS creates asymmetric force transmission under the saddle, and also influences back movement. To change the load distribution on the back of horses with potential back pain and as a training variation, a combination of both riding styles is suitable. |
Address |
Department V, Clinic of Orthopaedics in Ungulates, University of Veterinary Medicine, Veterinaerplatz 1, A-1210 Vienna, Austria |
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Notes |
PMID:17402456 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
4007 |
Permanent link to this record |
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Author |
Fruehwirth, B.; Peham, C.; Scheidl, M.; Schobesberger, H. |
Title |
Evaluation of pressure distribution under an English saddle at walk, trot and canter |
Type |
Journal Article |
Year |
2004 |
Publication |
Equine Veterinary Journal |
Abbreviated Journal |
Equine Vet J |
Volume |
36 |
Issue |
8 |
Pages |
754-757 |
Keywords |
Animals; Back/*physiology; Biomechanics; Body Weight/physiology; Exercise Test/veterinary; Gait/*physiology; Horses/*physiology; Humans; Locomotion/*physiology; Pressure |
Abstract |
REASONS FOR PERFORMING STUDY: Basic information about the influence of a rider on the equine back is currently lacking. HYPOTHESIS: That pressure distribution under a saddle is different between the walk, trot and canter. METHODS: Twelve horses without clinical signs of back pain were ridden. At least 6 motion cycles at walk, trot and canter were measured kinematically. Using a saddle pad, the pressure distribution was recorded. The maximum overall force (MOF) and centre of pressure (COP) were calculated. The range of back movement was determined from a marker placed on the withers. RESULTS: MOF and COP showed a consistent time pattern in each gait. MOF was 12.1 +/- 1.2 and 243 +/- 4.6 N/kg at walk and trot, respectively, in the ridden horse. In the unridden horse MOF was 172.7 +/- 11.8 N (walk) and 302.4 +/- 33.9 N (trot). At ridden canter, MOF was 27.2 +/- 4.4 N/kg. The range of motion of the back of the ridden horse was significantly lower compared to the unridden, saddled horse. CONCLUSIONS AND POTENTIAL RELEVANCE: Analyses may help quantitative and objective evaluation of the interaction between rider and horse as mediated through the saddle. The information presented is therefore of importance to riders, saddlers and equine clinicians. With the technique used in this study, style, skill and training level of different riders can be quantified, which would give the opportunity to detect potentially harmful influences and create opportunities for improvement. |
Address |
Movement Science Group, Department V, Clinic of Orthopaedics in Ungulates, University of Veterinary Medicine, Vienna, Austria |
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0425-1644 |
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Notes |
PMID:15656510 |
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
4041 |
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Author |
Cassiat, G.; Pourcelot, P.; Tavernier, L.; Geiger, D.; Denoix, J.M.; Degueurce, D. |
Title |
Influence of individual competition level on back kinematics of horses jumping a vertical fence |
Type |
Journal Article |
Year |
2004 |
Publication |
Equine Veterinary Journal |
Abbreviated Journal |
Equine Vet J |
Volume |
36 |
Issue |
8 |
Pages |
748-753 |
Keywords |
Animals; Back/*physiology; Biomechanics; Female; Forelimb/*physiology; Gait/*physiology; Hindlimb/*physiology; Horses/*physiology; Image Processing, Computer-Assisted; Imaging, Three-Dimensional/veterinary; Locomotion/physiology; Male; Video Recording |
Abstract |
REASONS FOR PERFORMING STUDY: The costs and investments required for the purchase and training of showjumpers justify the need to find selection means for jumping horses. Use of objective kinematic criteria correlated to jumping ability could be helpful for this assessment. OBJECTIVES: To compare back kinematics between 2 groups of horses of different competition levels (Group 1, competing at high level; Group 2 competing at low level) while free jumping over a 1 m vertical fence. METHODS: Three-dimensional recordings were performed using 2 panning cameras. Kinematic parameters of the withers and tuber sacrale (vertical displacement, vertical and horizontal velocities), backline inclination and flexion-extension motion of the 3 main dorsal segments (thoracic, thoracolumbar and lumbosacral) were analysed. RESULTS: Group 2 horses had a lower displacement of their withers and tuber sacrale from the end of the last approach stride until the first departure stride (P<0.05). As a result, they increased the flexion of their thoracolumbar and lumbosacral junctions during the hindlimb swing phase before take-off (P<0.05). However, withers and tuber sacrale velocities were slightly modified. Group 1 horses pitched their backline less forward during the forelimb stance phase before take-off and straightened it more after landing (P<0.05), probably indicating a more efficient strutting action of their forelimbs. CONCLUSIONS AND POTENTIAL RELEVANCE: Because significant differences in back motion were found between good and poor jumpers when jumping a 1 m high fence, criteria based on certain back kinematics can be developed that may help in the selection of talented showjumpers. |
Address |
UMR INRA-ENVA de Biomecanique et Pathologie Locomotrice du Cheval, Ecole Nationale Veterinaire d'Alfort, Avenue du General de Gaulle, 94704 Maisons Alfort, France |
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English |
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0425-1644 |
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PMID:15656509 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
4042 |
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Author |
Powers, P.; Harrison, A. |
Title |
Effects of the rider on the linear kinematics of jumping horses |
Type |
Journal Article |
Year |
2002 |
Publication |
Sports Biomechanics / International Society of Biomechanics in Sports |
Abbreviated Journal |
Sports Biomech |
Volume |
1 |
Issue |
2 |
Pages |
135-146 |
Keywords |
Animals; Behavior, Animal/*physiology; Biomechanics; Communication; Exertion/*physiology; Gait/*physiology; Horses/*physiology; Humans; Locomotion/*physiology; Posture/*physiology; Task Performance and Analysis; Video Recording; Weight-Bearing/*physiology |
Abstract |
This study examined the effects of the rider on the linear projectile kinematics of show-jumping horses. SVHS video recordings (50 Hz) of eight horses jumping a vertical fence 1 m high were used for the study. Horses jumped the fence under two conditions: loose (no rider or tack) and ridden. Recordings were digitised using Peak Motus. After digitising the sequences, each rider's digitised data were removed from the ridden horse data so that three conditions were examined: loose, ridden (including the rider's data) and riderless (rider's data removed). Repeated measures ANOVA revealed significant differences between ridden and loose conditions for CG height at take-off (p < 0.001), CG distance to the fence at take-off (p = 0.001), maximum CG during the suspension phase (p < 0.001), CG position over the centre of the fence (p < 0.001), CG height at landing (p < 0.001), and vertical velocity at take-off (p < 0.001). The results indicated that the rider's effect on jumping horses was primarily due to behavioural changes in the horses motion (resulting from the rider's instruction), rather than inertial effects (due to the positioning of the rider on the horse). These findings have implications for the coaching of riders and horses. |
Address |
Department of PE and Sports Sciences, University of Limerick, Limerick, Ireland |
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ISSN |
1476-3141 |
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PMID:14658371 |
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no |
Call Number |
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Serial |
1904 |
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Author |
Wilson, A.M.; McGuigan, M.P.; Su, A.; van Den Bogert, A.J. |
Title |
Horses damp the spring in their step |
Type |
Journal Article |
Year |
2001 |
Publication |
Nature |
Abbreviated Journal |
Nature |
Volume |
414 |
Issue |
6866 |
Pages |
895-899 |
Keywords |
Animals; Biomechanics; Elasticity; Forelimb; Gait; Horses/anatomy & histology/*physiology; Leg Bones/*physiology; Locomotion; Models, Biological; Muscle Fibers/physiology; Muscle, Skeletal/anatomy & histology/*physiology; Tendons/anatomy & histology/*physiology; Vibration |
Abstract |
The muscular work of galloping in horses is halved by storing and returning elastic strain energy in spring-like muscle-tendon units.These make the legs act like a child's pogo stick that is tuned to stretch and recoil at 2.5 strides per second. This mechanism is optimized by unique musculoskeletal adaptations: the digital flexor muscles have extremely short fibres and significant passive properties, whereas the tendons are very long and span several joints. Length change occurs by a stretching of the spring-like digital flexor tendons rather than through energetically expensive length changes in the muscle. Despite being apparently redundant for such a mechanism, the muscle fibres in the digital flexors are well developed. Here we show that the mechanical arrangement of the elastic leg permits it to vibrate at a higher frequency of 30-40 Hz that could cause fatigue damage to tendon and bone. Furthermore, we show that the digital flexor muscles have minimal ability to contribute to or regulate significantly the 2.5-Hz cycle of movement, but are ideally arranged to damp these high-frequency oscillations in the limb. |
Address |
Department of Veterinary Basic Sciences, The Royal Veterinary College, Hatfield, Herts AL9 7TA, UK. awilson@rvc.ac.uk |
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ISSN |
0028-0836 |
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Notes |
PMID:11780059 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
2300 |
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Author |
Robert, C.; Audigie, F.; Valette, J.P.; Pourcelot, P.; Denoix, J.M. |
Title |
Effects of treadmill speed on the mechanics of the back in the trotting saddlehorse |
Type |
Journal Article |
Year |
2001 |
Publication |
Equine Veterinary Journal. Supplement |
Abbreviated Journal |
Equine Vet J Suppl |
Volume |
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Issue |
33 |
Pages |
154-159 |
Keywords |
Animals; Biomechanics; Electromyography/veterinary; Exercise Test/veterinary; Horses/*physiology; Locomotion/*physiology; Muscle, Skeletal/*physiology; Range of Motion, Articular/*physiology; Spine/*physiology; Video Recording |
Abstract |
Speed related changes in trunk mechanics have not yet been investigated, although high-speed training is currently used in the horse. To evaluate the effects of speed on back kinematics and trunk muscles activity, 4 saddle horses were recorded while trotting on a horizontal treadmill at speeds ranging from 3.5 to 6 m/s. The 3-dimensional (3-D) trajectories of skin markers on the left side of the horse and the dorsal midline of the trunk were established. Electrical activity was simultaneously obtained from the longissimus dorsi (LD) and rectus abdominis (RA) muscles using surface electrodes. Ten consecutive strides were analysed for each horse at each of the 5 velocity steps. Electromyographic and kinematic data were time-standardised to the duration of the stride cycle and compared using an analysis of variance. The back extended during the first part of each diagonal stance phase when the RA was active and the back flexed during the second part of each diagonal stance phase when the LD was active. The onset and end of muscle activity came earlier in the stride cycle and muscle activity intensity increased when speed increased. The amplitude of vertical movement of the trunk and the maximal angles of flexion decreased with increasing speed, whereas the extension angles remained unchanged. This resulted in a decreased range of back flexion-extension. This study confirms that the primary role of trunk muscles is to control the stiffness of the back rather than to induce movements. Understanding the effects of speed on the back of healthy horses is a prerequisite for the prevention and treatment of back pathology. |
Address |
UMR INRA, Biomecanique et Pathologie Locomotrice du Cheval, UP d'Anatomie, Ecole Nationale Veterinaire d'Alfort, 7 Avenue du General de Gaulle, F-94704 Maisons-Alfort, France |
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English |
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PMID:11721558 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
4050 |
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Author |
Weishaupt, M.A.; Wiestner, T.; von Peinen, K.; Waldern, N.; Roepstorff, L.; van Weeren, R.; Meyer, H.; Johnston, C. |
Title |
Effect of head and neck position on vertical ground reaction forces and interlimb coordination in the dressage horse ridden at walk and trot on a treadmill |
Type |
Journal Article |
Year |
2006 |
Publication |
Equine Veterinary Journal. Supplement |
Abbreviated Journal |
Equine Vet J Suppl |
Volume |
|
Issue |
36 |
Pages |
387-392 |
Keywords |
Animals; Biomechanics; Exercise Test/instrumentation/methods/*veterinary; Forelimb/physiology; Gait; Head/physiology; Hindlimb/physiology; Horses/*physiology; Locomotion/*physiology; Male; Neck/physiology; Physical Conditioning, Animal/methods/*physiology; Posture; Statistics, Nonparametric; Walking/*physiology |
Abstract |
REASONS FOR PERFORMING STUDY: Little is known in quantitative terms about the influence of different head-neck positions (HNPs) on the loading pattern of the locomotor apparatus. Therefore it is difficult to predict whether a specific riding technique is beneficial for the horse or if it may increase the risk for injury. OBJECTIVE: To improve the understanding of forelimb-hindlimb balance and its underlying temporal changes in relation to different head and neck positions. METHODS: Vertical ground reaction force and time parameters of each limb were measured in 7 high level dressage horses while being ridden at walk and trot on an instrumented treadmill in 6 predetermined HNPs: HNP1 – free, unrestrained with loose reins; HNP2 – neck raised, bridge of the nose in front of the vertical; HNP3 – neck raised, bridge of the nose behind the vertical; HNP4 – neck lowered and flexed, bridge of the nose considerably behind the vertical; HNP5 – neck extremely elevated and bridge of the nose considerably in front of the vertical; HNP6 – neck and head extended forward and downward. Positions were judged by a qualified dressage judge. HNPs were assessed by comparing the data to a velocity-matched reference HNP (HNP2). Differences were tested using paired t test or Wilcoxon signed rank test (P<0.05). RESULTS: At the walk, stride duration and overreach distance increased in HNP1, but decreased in HNP3 and HNP5. Stride impulse was shifted to the forehand in HNP1 and HNP6, but shifted to the hindquarters in HNP5. At the trot, stride duration increased in HNP4 and HNP5. Overreach distance was shorter in HNP4. Stride impulse shifted to the hindquarters in HNP5. In HNP1 peak forces decreased in the forelimbs; in HNP5 peak forces increased in fore- and hindlimbs. CONCLUSIONS: HNP5 had the biggest impact on limb timing and load distribution and behaved inversely to HNP1 and HNP6. Shortening of forelimb stance duration in HNP5 increased peak forces although the percentage of stride impulse carried by the forelimbs decreased. POTENTIAL RELEVANCE: An extremely high HNP affects functionality much more than an extremely low neck. |
Address |
Equine Hospital, University of Zurich, CH-8057 Zurich, Switzerland |
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|
Notes |
PMID:17402453 |
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3704 |
Permanent link to this record |