Records |
Author |
Witte, T.H.; Knill, K.; Wilson, A.M. |
Title |
Determination of peak vertical ground reaction force from duty factor in the horse (Equus caballus) |
Type |
Journal Article |
Year |
2004 |
Publication |
The Journal of Experimental Biology |
Abbreviated Journal |
J Exp Biol |
Volume |
207 |
Issue |
Pt 21 |
Pages |
3639-3648 |
Keywords ![sorted by Keywords field, descending order (down)](img/sort_desc.gif) |
*Acceleration; Animals; Biomechanics; Forelimb/physiology; *Gait; Hindlimb/physiology; Horses/*physiology; Locomotion/*physiology; Telemetry; Time Factors |
Abstract |
Measurement of peak vertical ground reaction force (GRFz) from multiple limbs simultaneously during high-speed, over-ground locomotion would enhance our understanding of the locomotor mechanics of cursorial animals. Here, we evaluate the accuracy of predicting peak GRFz from duty factor (the proportion of the stride for which the limb is in contact with the ground). Foot-mounted uniaxial accelerometers, combined with UHF FM telemetry, are shown to be practical and accurate for the field measurement of stride timing variables, including duty factor. Direct comparison with the force plate produces a mean error of 2.3 ms and 3.5 ms for the timing of foot on and foot off, respectively, across all gaits. Predictions of peak GRFz from duty factor show mean errors (with positive values indicating an overestimate) of 0.8+/-0.04 N kg(-1) (13%; N=42; mean +/- S.E.M.) at walk, -0.3+/-0.06 N kg(-1) (3%; N=75) at trot, -2.3+/-0.27 N kg(-1) (16%; N=18) for the non-lead limb at canter and +2.1+/-0.7 N kg(-1) (19%; N=9) for the lead limb at canter. The substantial over- and underestimate seen at canter, in the lead and non-lead limbs, respectively, is attributed to the different functions performed by the two limbs in the asymmetrical gaits. The difference in load experienced by the lead and non-lead limbs decreased with increasing speed. |
Address |
Structure and Motion Lab, The Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, AL9 7TA, UK |
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English |
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ISSN |
0022-0949 |
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Notes |
PMID:15371472 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3658 |
Permanent link to this record |
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Author |
Barrey, E.; Galloux, P. |
Title |
Analysis of the equine jumping technique by accelerometry |
Type |
Journal Article |
Year |
1997 |
Publication |
Equine Veterinary Journal. Supplement |
Abbreviated Journal |
Equine Vet J Suppl |
Volume |
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Issue |
23 |
Pages |
45-49 |
Keywords ![sorted by Keywords field, descending order (down)](img/sort_desc.gif) |
*Acceleration; Analysis of Variance; Animals; Forelimb/physiology; Hindlimb/physiology; Horses/*physiology; Locomotion/*physiology; Movement/physiology; Time Factors |
Abstract |
The purpose of this study was to demonstrate the relationships between jumping technique and dorsoventral acceleration measured at the sternum. Eight saddle horses of various jumping abilities competed on a selective experimental show jumping course including 14 obstacles. An accelerometric belt fastened onto the thorax continuously measured the dorsoventral acceleration during the course. At each jump, 11 locomotor parameters (acceleration peaks, durations and stride frequency) were obtained from the dorsoventral acceleration-time curves. The type of obstacle significantly influenced the hindlimb acceleration peak at take-off and the landing acceleration peak (P<0.01). The poor jumpers exhibited a higher mean forelimb acceleration peak at take-off, a higher forelimb/hindlimb ratio between peaks of acceleration (F/H), and a lower approach stride frequency than good jumpers. Knocking over an obstacle was significantly associated with a low hindlimb acceleration peak at take-off and a high F/H ratio (P<0.01). In order to observe the continuous changes in the frequency domain of the dorsoventral acceleration during the approach and take-off phase, a Morlet's wavelet analysis was computed for each horse jumping over a series of 3 vertical obstacles. Different patterns of time-frequency images obtained by wavelet analysis were found when the horse either knocked over a vertical obstacle or cleared it. In the latter case, the image pattern showed an instantaneous increase in stride frequency at the end of the approach phase, and a marked energy content in the middle frequency range at take-off. |
Address |
INRA Station de Genetique Quantitative et Appliquee, Groupe cheval, Jouy-en-Josas, France |
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English |
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PMID:9354288 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3796 |
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Author |
Santamaria, S.; Bobbert, M.E.; Back, W.; Barneveld, A.; van Weeren, P.R. |
Title |
Variation in free jumping technique within and among horses with little experience in show jumping |
Type |
Journal Article |
Year |
2004 |
Publication |
American Journal of Veterinary Research |
Abbreviated Journal |
Am J Vet Res |
Volume |
65 |
Issue |
7 |
Pages |
938-944 |
Keywords ![sorted by Keywords field, descending order (down)](img/sort_desc.gif) |
*Acceleration; Analysis of Variance; Animals; Biomechanics; Forelimb/physiology; Gait/*physiology; Hindlimb/physiology; Horses/*physiology; Locomotion/*physiology; Models, Biological; Video Recording |
Abstract |
OBJECTIVE: To quantify variation in the jumping technique within and among young horses with little jumping experience, establish relationships between kinetic and kinematic variables, and identify a limited set of variables characteristic for detecting differences in jumping performance among horses. ANIMALS: Fifteen 4-year-old Dutch Warmblood horses. PROCEDURE: The horses were raised under standardized conditions and trained in accordance with a fixed protocol for a short period. Subsequently, horses were analyzed kinematically during free jumping over a fence with a height of 1.05 m. RESULTS: Within-horse variation in all variables that quantified jumping technique was smaller than variation among horses. However, some horses had less variation than others. Height of the center of gravity (CG) at the apex of the jump ranged from 1.80 to 2.01 m among horses; this variation could be explained by the variation in vertical velocity of the CG at takeoff (r, 0.78). Horses that had higher vertical velocity at takeoff left the ground and landed again farther from the fence, had shorter push-off phases for the forelimbs and hind limbs, and generated greater vertical acceleration of the CG primarily during the hind limb push-off. However, all horses cleared the fence successfully, independent of jumping technique. CONCLUSIONS AND CLINICAL RELEVANCE: Each horse had its own jumping technique. Differences among techniques were characterized by variations in the vertical velocity of the CG at takeoff. It must be determined whether jumping performance later in life can be predicted from observing free jumps of young horses. |
Address |
Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 12, NL-3584 CM Utrecht, The Netherlands |
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English |
Summary Language |
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Original Title |
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Series Editor |
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Abbreviated Series Title |
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Edition |
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ISSN |
0002-9645 |
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Notes |
PMID:15281652 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3772 |
Permanent link to this record |