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Author Dutto, D.J.; Hoyt, D.F.; Clayton, H.M.; Cogger, E.A.; Wickler, S.J. openurl 
  Title Moments and power generated by the horse (Equus caballus) hind limb during jumping Type Journal Article
  Year 2004 Publication The Journal of Experimental Biology Abbreviated Journal J Exp Biol  
  Volume 207 Issue Pt 4 Pages 667-674  
  Keywords Animals; Biomechanics; Hindlimb/*physiology; Horses/*physiology; Locomotion/*physiology  
  Abstract The ability to jump over an obstacle depends upon the generation of work across the joints of the propelling limb(s). The total work generated by one hind limb of a horse and the contribution to the total work by four joints of the hind limb were determined for a jump. It was hypothesized that the hip and ankle joints would have extensor moments performing positive work, while the knee would have a flexor moment and perform negative work during the jump. Ground reaction forces and sagittal plane kinematics were simultaneously recorded during each jumping trial. Joint moment, power and work were determined for the metatarsophalangeal (MP), tarsal (ankle), tibiofemoral (knee) and coxofemoral (hip) joints. The hip, knee and ankle all flexed and then extended and the MP extended and then flexed during ground contact. Consistent with our hypothesis, large extensor moments were observed at the hip and ankle joints and large flexor moments at the knee and MP joints throughout ground contact of the hind limb. Peak moments tended to occur earlier in stance in the proximal joints but peak power generation of the hind limb joints occurred at similar times except for the MP joint, with the hip and ankle peaking first followed by the MP joint. During the first portion of ground contact (approximately 40%), the net result of the joint powers was the absorption of power. During the remainder of the contact period, the hind limb generated power. This pattern of power absorption followed by power generation paralleled the power profiles of the hip, ankle and MP joints. The total work performed by one hind limb was 0.71 J kg(-1). Surprisingly, the knee produced 85% of the work (0.60 J kg(-1)) done by the hind limb, and the positive work performed by the knee occurred during the first 40% of the take-off. There is little net work generated by the other three joints over the entire take-off. Velocity of the tuber coxae (a landmark on the pelvis of the animal) was negative (downward) during the first 40% of stance, which perhaps reflects the negative work performed to decrease the potential energy during the first 40% of contact. During the final 60% of contact, the hip, ankle and MP joints generate positive work, which is reflected in the increase of the animal's potential energy.  
  Address Department of Kinesiology and Health Promotion, California State Polytechnic University, Pomona, CA 91768, USA. ddutto@csupomona.edu  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume (down) Series Issue Edition  
  ISSN 0022-0949 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:14718509 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3654  
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Author Clayton, H.M.; Lanovaz, J.L.; Schamhardt, H.C.; van Wessum, R. openurl 
  Title The effects of a rider's mass on ground reaction forces and fetlock kinematics at the trot Type Journal Article
  Year 1999 Publication Equine Veterinary Journal. Supplement Abbreviated Journal Equine Vet J Suppl  
  Volume 30 Issue Pages 218-221  
  Keywords Animals; Body Weight; Computer Simulation; Gait/*physiology; Horses/*physiology; Physical Conditioning, Animal/*physiology; Stress, Mechanical; Weight-Bearing/*physiology  
  Abstract Ground reaction force (GRF) measurements are often normalised to body mass to facilitate inter-individual comparisons. The objective of this study was to explore the effect of a rider on the GRFs and fetlock joint kinematics of trotting horses. The subjects were 5 dressage-trained horses and 3 experienced dressage riders. Ground reaction force measurements and sagittal view videotapes were recorded as the horses trotted at the same velocity in hand (3.49 +/- 0.52 m/s) and with a rider (3.49 +/- 0.46 m/s). Data were time-normalised to stance duration. Ground reaction force measurements were expressed in absolute terms and normalised to the system mass (horse or horse plus rider). All the horses showed changes in the same direction when comparing the ridden condition with the in-hand condition. There was an increase in the absolute peak vertical GRFs of the fore- and hindlimbs with a rider. However, the mass-normalised peak vertical GRFs were lower for the ridden condition, with the peak occurring later in the forelimbs and earlier in the hindlimbs compared with the inhand condition. Maximal fetlock angle and its time of occurrence were similar for the 2 conditions, but the fore fetlock joint was more extended during the later part of the stance phase in ridden horses. The presence of a rider appeared to affect the GRFs and fetlock joint kinematics differently in the fore- and hindlimbs, and the ridden horse did not seem to be equivalent to a proportionately larger horse. This should be considered when normalising for body mass in studies comparing horses in hand and ridden horses.  
  Address Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824-1314, USA  
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  Notes PMID:10659255 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3733  
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Author Burns, T.E.; Clayton, H.M. openurl 
  Title Comparison of the temporal kinematics of the canter pirouette and collected canter Type Journal Article
  Year 1997 Publication Equine Veterinary Journal. Supplement Abbreviated Journal Equine Vet J Suppl  
  Volume Issue 23 Pages 58-61  
  Keywords Animals; Forelimb/physiology; Gait/*physiology; Hindlimb/physiology; Horses/*physiology; Locomotion/*physiology; Movement/physiology; Time Factors; Videotape Recording; Walking/physiology  
  Abstract The objectives were to compare the temporal characteristics of canter pirouette strides with collected canter strides in elite dressage horses, and to determine whether the stride kinematics of the canter pirouettes fulfilled the requirements specified in the Federation Equestre Internationale Rules for Dressage Events. Eleven horses were videotaped (60 fields/s) during the individual medal competition at the 1992 Olympic Games. Temporal variables were extracted from the videotapes using standard methods. Two strides were analysed on each of the left and right leads and these were pooled to give mean values for the collected canter and the pirouettes. The pirouettes were completed in 4-9 strides, (mean of 6.4). In the collected canter strides, mean duration of the suspension was 0.013 s. There was no suspension in any of the pirouette strides, instead the stance phases of the leading forelimb and trailing hindlimb overlapped by a mean of 0.163 s. In 9 horses the trailing forelimb contacted the ground before the diagonal leading hindlimb in the collected canter, whereas in the pirouettes the leading hindlimb always made contact before the trailing forelimb (mean dissociation 0.164 s), giving the strides a distinct 4 beat rhythm. Due to increases in advanced placement between the diagonal limb pair and between the 2 forelimbs, the stride duration was longer in the pirouette (0.879 s) than the collected canter (0.629 s). It is concluded that the canter pirouette strides did not maintain the rhythm and timing of the the collected canter strides in any of the 11 horses.  
  Address Department of Veterinary Anatomy, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada  
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  Notes PMID:9354291 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3737  
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Author Clayton, H.M. openurl 
  Title Classification of collected trot, passage and piaffe based on temporal variables Type Journal Article
  Year 1997 Publication Equine Veterinary Journal. Supplement Abbreviated Journal Equine Vet J Suppl  
  Volume Issue 23 Pages 54-57  
  Keywords Analysis of Variance; Animals; Discriminant Analysis; Gait/*physiology; Hindlimb/physiology; Horses/*physiology; Locomotion/*physiology; Male; Running/physiology; Time Factors; Videotape Recording; Walking/physiology  
  Abstract The objective was to determine whether collected trot, passage and piaffe could be distinguished as separate gaits on the basis of temporal variables. Sagittal plane, 60 Hz videotapes of 10 finalists in the dressage competitions at the 1992 Olympic Games were analysed to measure the temporal variables in absolute terms and as percentages of stride duration. Classification was based on analysis of variance, a graphical method and discriminant analysis. Stride duration was sufficient to distinguish collected trot from passage and piaffe in all horses. The analysis of variance showed that the mean values of most variables differed significantly between passage and piaffe. When hindlimb stance percentage was plotted against diagonal advanced placement percentage, some overlap was found between all 3 movements indicating that individual horses could not be classified reliably in this manner. Using hindlimb stance percentage and diagonal advanced placement percentage as input in a discriminant analysis, 80% of the cases were classified correctly, but at least one horse was misclassified in each movement. When the absolute, rather than percentage, values of the 2 variables were used as input in the discriminant analysis, 90% of the cases were correctly classified and the only misclassifications were between passage and piaffe. However, the 2 horses in which piaffe was misclassified as passage were the gold and silver medallists. In general, higher placed horses tended toward longer diagonal advanced placements, especially in collected trot and passage, and shorter hindlimb stance percentages in passage and piaffe.  
  Address Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada  
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  Notes PMID:9354290 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3738  
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Author Clayton, H.M. openurl 
  Title Comparison of the stride kinematics of the collected, medium, and extended walks in horses Type Journal Article
  Year 1995 Publication American Journal of Veterinary Research Abbreviated Journal Am J Vet Res  
  Volume 56 Issue 7 Pages 849-852  
  Keywords Analysis of Variance; Animals; *Gait; Horses/*physiology; *Locomotion; Motion Pictures; Physical Conditioning, Animal; Walking  
  Abstract Six horses, highly trained for dressage competition, were used to study the stride kinematics of the walk, and to compare the kinematics of the collected, medium, and extended walks. Horses were filmed in a sagittal plane at a rate of 150 frames/s; temporal, linear, and angular data were extracted from the films. Results of ANOVA and Duncan's multiple range test indicated that the speed of the collected walk (1.37 m/s) was significantly (P < 0.01) slower than that of the medium (1.73 m/s) and extended (1.82 m/s) walks, values for which were not significantly different from each other. The increase in speed was associated with a significant increase in stride length, from 157 cm in the collected walk to 193 cm in the extended walk. This was a result of an increase in the over-tracking distance, whereas there was no significant difference in the distance between lateral placements of the limbs. Stride duration decreased (P < 0.01) from the collected walk (1,159 ms) to the extended walk (1,064 ms). Angles of the metacarpal and metatarsal segments, measured on the palmar/ plantar aspect, were higher at impact and lower at lift off in the collected than in the extended walk (P < 0.01). This indicated greater range of angular motion of this segment during the stance phase in the extended walk. Only 1 of the 6 horses had a regular 4-beat rhythm of the footfalls, with equal time elapsing between the lateral and diagonal footfalls.  
  Address Department of Veterinary Anatomy, Western College of Veterinary Medicine, Canada  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume (down) Series Issue Edition  
  ISSN 0002-9645 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:7574149 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3743  
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Author Clayton, H.M. openurl 
  Title Comparison of the stride kinematics of the collected, working, medium and extended trot in horses Type Journal Article
  Year 1994 Publication Equine Veterinary Journal Abbreviated Journal Equine Vet J  
  Volume 26 Issue 3 Pages 230-234  
  Keywords Analysis of Variance; Animals; Biomechanics; Female; Forelimb/anatomy & histology/physiology; Gait/*physiology; Hindlimb/anatomy & histology/physiology; Horses/anatomy & histology/*physiology; Locomotion/physiology; Male; Motion Pictures  
  Abstract Highly-trained dressage horses were studied to test the hypothesis that stride length is altered independently of stride duration in the transitions between the collected, working, medium and extended trot. Six well-trained dressage horses were filmed at a frame rate of 150 frames/s performing the collected, working, medium and extended trots in a sand arena. Temporal, linear and angular data were extracted from the films, with 4 strides being analysed for each horse and gait type. There were no significant asymmetries between the left and rights limbs or diagonals when data from the whole group were pooled, but 3 horses showed asymmetries in one or more variables (P < 0.01). Analysis of variance and post-hoc tests indicated that the speed increased significantly (P < 0.01) from the collected (3.20 m/s) to the working (3.61 m/s) to the medium (4.47 m/s) to the extended (4.93 m/s) trot. The increases in speed were associated with a significant increase in stride length from 250 cm in the collected trot, to 273 cm in the working trot, 326 cm in the medium trot and 355 cm in the extended trot (P < 0.01). The lengthening of the stride was a result of increases between each gait type in the over-reach distance, whereas the diagonal distance was significantly longer in the extended than the collected trot only (P < 0.01). The stride duration tended to decrease as speed increased, and the difference became significant between the collected and extended trots (P < 0.01).  
  Address Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume (down) Series Issue Edition  
  ISSN 0425-1644 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:8542844 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3746  
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Author Clayton, H.M. openurl 
  Title Development of conditioning programs for dressage horses based on time-motion analysis of competitions Type Journal Article
  Year 1993 Publication Journal of Applied Physiology (Bethesda, Md. : 1985) Abbreviated Journal J Appl Physiol  
  Volume 74 Issue 5 Pages 2325-2329  
  Keywords Animals; Horses/*physiology; *Physical Conditioning, Animal; *Sports; Statistics; Time Factors; *Time and Motion Studies; Videotape Recording  
  Abstract The time-motion characteristics of Canadian basic- and medium-level dressage competitions are described, and the results are applied in formulating sport-specific conditioning programs. One competition was analyzed at the six levels from basic 1 to medium 3. Each test was divided into a series of sequences based on the type and speed of activity. The durations of the sequences were measured from videotapes. The basic-level tests had fewer sequences, and they were shorter in distance and duration than the medium tests (P < 0.10), but the average speed did not differ between the two levels. It is recommended that horses competing at the basic levels be conditioned using 5-min exercise periods, with short (10-s) bursts of lengthened trot and canter included at basic 2 and above. In preparation for medium-level competitions, the duration of the work periods increases to 7 min, 10- to 12-s bursts of medium or extended trot and canter are included, and transitions are performed frequently to simulate the energy expenditure in overcoming inertia.  
  Address Department of Veterinary Anatomy, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume (down) Series Issue Edition  
  ISSN 8750-7587 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:8335563 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3750  
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Author Clayton, H.M. openurl 
  Title The extended canter: a comparison of some kinematic variables in horses trained for dressage and for racing Type Journal Article
  Year 1993 Publication Acta Anatomica Abbreviated Journal Acta Anat (Basel)  
  Volume 146 Issue 2-3 Pages 183-187  
  Keywords Animal Husbandry; Animals; *Gait; Horses/*physiology; *Physical Conditioning, Animal; *Sports  
  Abstract This study was designed to test the hypothesis that there is no significant difference in selected temporal and linear stride variables of the extended canter in horses bred and trained for dressage or racing. Nine advanced-level dressage horses and 7 Thoroughbred racehorses were filmed at a frame rate of 200 Hz at an extended canter on a sand track. Two strides were recorded per trial, and each horse performed 6 or 7 trials. Temporal and linear data were determined from the films, and descriptive statistics (mean, SD) were calculated. Strides were selected for analysis on the basis of having a velocity in the range of 6.0-7.0 m/s, and multivariate analysis of variance was used to detect significant differences in the stride kinematics of horses trained for the two sports (p < or = 0.01). The average velocity of the dressage horses was 6.37 m/s, compared with 6.40 m/s for the racehorses. There were no significant differences between the two groups in velocity, stride duration, stride length or the distances between limb placements. The stance durations of all four limbs and the overlaps between them were longer, whereas the duration of the suspension phase was shorter in the dressage horses than in the racehorses (p < or = 0.01). The time between impacts of the diagonal limb pair was close to zero in both groups, with individual horses showing some variability in the order of placement of the diagonal limb pair. However, the sequence of footfalls was not significantly different between the two groups (p < or = 0.01).  
  Address Department of Veterinary Anatomy, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume (down) Series Issue Edition  
  ISSN 0001-5180 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:8470464 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3751  
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Author Argue, C.K.; Clayton, H.M. openurl 
  Title A preliminary study of transitions between the walk and trot in dressage horses Type Journal Article
  Year 1993 Publication Acta Anatomica Abbreviated Journal Acta Anat (Basel)  
  Volume 146 Issue 2-3 Pages 179-182  
  Keywords Animals; Forelimb/physiology; Gait/*physiology; Hindlimb/physiology; Horses/*physiology; Locomotion/physiology; *Physical Conditioning, Animal  
  Abstract The object of this study was to determine the limb support sequence during the transitions from walk to trot and from trot to walk in dressage horses under saddle and to test the null hypothesis that the limb support sequence during the transitions is not related to the level of training. Sixteen dressage horses training at novice to FEI Grand Prix level were videotaped performing an average of 9 transitions each from walk to trot and from trot to walk. The 30-Hz videotapes were viewed in slow motion, and based on the limb support sequence the transitions were categorized into two types. In type 1 transitions there were no intermediate steps between the walk and trot sequences. Type 2 transitions were characterized by intermediate steps, including a single support phase. The Kendall rank-order correlation coefficient showed that a higher level of training was positively associated with an increased percentage of type 1 transitions for both walk-to-trot transitions (p < or = 0.05) and trot-to-walk transitions (p < or = 0.01). No significant preference for initiating or completing the trot on the left or right diagonal was found using the binomial test for individual horses and the Wilcoxon signed-ranks test for the group.  
  Address Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume (down) Series Issue Edition  
  ISSN 0001-5180 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:8470463 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3752  
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Author Hodson, E.F.; Clayton, H.M.; Lanovaz, J.L. url  openurl
  Title Temporal analysis of walk movements in the Grand Prix dressage test at the 1996 Olympic Games Type Journal Article
  Year 1999 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.  
  Volume 62 Issue 2-3 Pages 89-97  
  Keywords Dressage; Horse; Kinematics; Locomotion; Gait  
  Abstract Video analysis was used to measure temporal characteristics of the collected walk, extended walk and half pirouette at walk of eleven competitors during the team dressage competition at the 1996 Summer Olympic Games in Atlanta, GA. Forelimb stance durations, hind limb stance durations, lateral step intervals and diagonal step intervals were symmetrical for the right and left sides in the collected and extended walk strides, but there were left-right asymmetries in the forelimb stance duration and in the lateral step interval in the half pirouette strides. For both collected and extended walk strides, hind limb stance duration was significantly longer than forelimb stance duration. The mean values for the group of eleven horses showed that the collected and extended walks had a regular rhythm. The half pirouette strides showed an irregularity in which there was a short interval between footfalls of the outside forelimb and inside hind limb, and along interval between footfalls of the inside hind limb and inside forelimb. This irregularity reflected an early placement of the inside hind limb. The stance times of both hind limbs were prolonged and this finding, in combination with the early placement of the inside hind limb, led to an increase in the period of tripedal support in each stride of the half pirouette. This was interpreted as a means of maintaining the horses' balance in the absence of forward movement.  
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  Notes Approved no  
  Call Number refbase @ user @ Serial 3960  
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