| 1. |
- Egenvall, Agneta, et al.
(författare)
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Modelling rein tension during riding sessions using the generalised additive modelling technique
- 2018
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Ingår i: Comparative Exercise Physiology. - 1755-2540 .- 1755-2559. ; 14, s. 209-221
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Tidskriftsartikel (refereegranskat)abstract
- General additive modelling (GAM-modelling) is an exploratory technique that can be used on longitudinal (time series) data, e.g. rein tension, over a period of time. The aim was to apply GAM-modelling to investigate changes in rein tension during a normal flatwork training session. Six riders each rode two or three of their horses (n=17 horses) during a normal flatwork/dressage training session with video recordings and rein tension measurements (128 Hz). Training sessions were classified according to rider position, stride length and whether horses were straight, bent to the left or bent to the right. The rein tension data were split into strides and for each stride minimal (MIN) and maximal (MAX) rein tension were determined and the area under the rein tension curve (AUC) was calculated. Using data on a contact the three outcome variables MIN, MAX and AUC rein tension were modelled by horse and rein (left/right), and time within the session was modelled as a smooth function. Two additional sets of models were constructed; one set using data within-rein with gait as a fixed effect and one set with rein and gait as fixed effects. Mean ± standard deviation values were MIN: 8.0±7.7 N, AUC: 180±109 Ns, and MAX: 49±31 N. GAM-modelling extracted visually interpretable information from the originally chaotic rein tension signals. Modelled data suggest that MIN, AUC and MAX follow the same pattern within horse. In general, rein tension was lowest in walk, intermediate in trot and highest in canter. Evaluating the entire ride, 12/17 horses systematically showed higher tension in the right rein. It is concluded that GAM-models may be useful for detecting patterns through time in biomechanical data.
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| 2. |
- Byström, Anna, et al.
(författare)
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Asymmetries of horses walking and trotting on treadmill with and without rider
- 2020
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Ingår i: Equine Veterinary Journal. - : Wiley. - 0425-1644 .- 2042-3306. ; 53, s. 157-166
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Tidskriftsartikel (refereegranskat)abstract
- Background Left-right movement symmetry is a highly desirable characteristic in sport horses.Objectives This study compared movement symmetry in well-trained dressage horses in unridden and unrestrained position and ridden in a dressage frame, and investigated possible associations between gaits.Study design Experimental study.Methods Seven sound, high-level dressage horses were measured at walk and sitting trot on a treadmill at several speeds under two conditions: with and without rider. Left-right differences in stance duration, stance protraction and retraction based on longitudinal hoof positions, ipsilateral limb tracking, minimum and maximum vertical positions of the dorsal spinous processes of the sixth thoracic (T6), third sacral vertebrae (S3) and wing of atlas, and vertical ground reaction forces were calculated and analysed in mixed models.Results At walk, five body variables indicated increased asymmetry in the ridden condition compared with unridden condition: forelimb stance duration (unridden/ridden left-right differences 9 vs 13 ms; P = .008), forelimb stance protraction (P = .004), stance retraction (P = .001) and first force peak (P = .003), and hindlimb stance retraction (P = .01). At trot, six body variables were more asymmetrical in the ridden condition: forelimb stance duration (2.5 vs 3.8 ms, P = .004); hindlimb stance protraction (P < .0001) and retraction (P = .01), T6 minimum (4 vs 6 mm, P = .001), T6 maximum (9 vs 11 mm, P = .01) and S3 maximum (6 vs 12 mm, P < .001). Five variables had significant associations between asymmetries at walk and trot, but only three demonstrated a positive slope.Main limitations A limited number of horses and riders were studied. Measurements were performed on a treadmill.Conclusions High-level horses moved slightly more asymmetrically when ridden in a dressage frame than in the unridden condition.
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| 3. |
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| 4. |
- Byström, Anna, et al.
(författare)
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Biomechanical findings in horses showing asymmetrical vertical excursions of the withers at walk
- 2018
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- The walk and trot are inherently symmetrical gaits, making them potentially suitable for the detection of left-right asymmetries. The aims of this study were to describe asymmetrical vertical excursions of the withers at walk in non-lame high-level dressage horses and to seek associations between these asymmetric movements and other kinematic variables and vertical ground reaction forces (vGRFs). Seven dressage horses, judged clinically as being sound, walked unridden and unrestrained on a treadmill with an integrated force measuring system (480 Hz), from which spatiotemporal and vGRF variables were extracted. Markers were tracked by 12 infrared cameras (240 Hz). The vertical position of the sixth thoracic vertebra (T6), limb protraction and retraction distances throughout stance, and global limb lengths were determined. Contralateral trial-mean differences were calculated, including difference in T6 minimum vertical position between contralateral steps (T6minDiff). Mixed models were used to study associations between symmetry parameters. Trial-mean T6minDiff ranged between 0.3-23 mm. Of the seven horses, five consistently dropped the withers more in early left forelimb stance, one was fairly symmetrical, and one dropped the withers more in early right forelimb stance. Comparisons between contralateral limbs showed the following associations. The forelimb that was retracted when T6min was lowest showed greater retraction at toe-off (1 mm increase predicted 0.17 mm T6minDiff increase) and shorter stance duration (1 ms decrease predicted 0.3 mm T6minDiff increase). The hind limb that was in midstance when T6min was lowest showed a greater range of motion during the stance phase (1 mm increase in protraction or retraction predicted 0.2 mm T6minDiff increase). The haunches were displaced away from the side of the forelimb that was protracted when T6min was lowest (1 mm lateral shift predicted 0.07 mm T6minDiff increase). Forelimb and hind limb vGRF parameters were non-significant. Asymmetry of vertical withers movement in horses assessed as being sound at trot was related to a complex pattern of asymmetries in spatiotemporal variables throughout the stride cycle rather than to vertical load redistribution between the forelimbs. This suggests that the asymmetry may be due to inherent laterality rather than weight-bearing lameness.
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| 5. |
- Byström, Anna, et al.
(författare)
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Differences in rider movement pattern between different degrees of collection at the trot in high-level dressage horses ridden on a treadmill
- 2015
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Ingår i: Human Movement Science. - : Elsevier BV. - 0167-9457 .- 1872-7646. ; 41, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Collection is a central term in equine dressage, defined as a shortening of the horse's stride length with retained energy and hind limb activity. How collection is induced by the rider has yet not been investigated objectively. The aim of this study was therefore to compare the movement pattern of high-level dressage riders between free trot (loose reins), passage and a range of three speeds in collected trot.Both at higher speed in collected trot and in passage, the rider's pelvis became more caudally rotated and the rider's lumbar back became more flexed. However, in passage there was also a decrease in phase-shift between horse and rider movements, suggesting that the rider used the seat more actively. In free trot, the rider's pelvis was more cranially rotated, the lumbar back was more extended, the rider's body inclined more forwards, and the phase-shift between horse and rider was increased, compared to collected trot. The observed changes were partly explainable from changes in the horse's movement pattern. However, most differences in rider body position seemed unrelated to the horse's movements, but were in accordance with instructions in equestrian texts, suggesting that those changes were voluntarily adopted by the riders. (C) 2015 Elsevier B.V. All rights reserved.
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| 6. |
- Byström, Anna, et al.
(författare)
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Kinematics of saddle and rider in high-level dressage horses performing collected walk on a treadmill
- 2010
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Ingår i: Equine Veterinary Journal. - : Wiley. - 0425-1644 .- 2042-3306. ; 42, s. 340-345
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Tidskriftsartikel (refereegranskat)abstract
- The literature suggests that the rider's influence on the movement pattern of the horse is the strongest at walk. For assessment of the horse-rider interaction in dressage horses presented for unsatisfactory performance, evaluations at walk may therefore be the most rewarding. Basic knowledge about rider and saddle movements in well-performing horses is likely to be supportive to this task.
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| 7. |
- Byström, Anna, et al.
(författare)
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Lateral movement of the saddle relative to the equine spine in rising and sitting trot on a treadmill
- 2018
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Saddle slip, defined as a progressive lateral displacement of the saddle during ridden exercise, has recently been given attention in the scientific press as a potential sign of lameness. The aim of this study was to objectively quantify the normal lateral movement (oscillations) of the saddle relative to the horse in non-lame horses, and associate this movement to the movements of the horse and rider. Data from seven Warmblood dressage horses competing at Grand Prix (n = 6) or FEI Intermediate (n = 1) level, ridden by their usual riders, were used. Simultaneous kinetic, kinematic and saddle pressure measurements were conducted during sitting and rising trot on a force-measuring treadmill. The maximum lateral movement of the caudal part of the saddle relative to the horse's spine (MAX) was determined for each diagonal step. A mixed model was applied, with MAX as outcome, and T6 and S3 vertical position, rigid body rotation angles (roll, pitch, yaw) of the horse's and rider's pelvis, vertical ground reaction forces, saddle force, and rider position (rising in rising trot, sitting in rising trot or sitting in sitting trot) as explanatory variables. The least square means for MAX were 14.3 (SE 4.7) mm and 23.9 (SE 4.7) mm for rising and sitting in rising trot, and 20.3 (SE 4.7) mm for sitting trot. A 10 mm increase in maximum pelvic height at push off increased MAX by 1.4 mm (p<0.0001). One degree increase in rider pelvis roll decreased MAX 1.1 mm, and one degree increase in rider pelvis yaw increased MAX 0.7 mm (both p<0.0001). The linear relationships found between MAX and movements of both horse and rider implies that both horse and rider movement asymmetries are reflected in the lateral movements or oscillations of the saddle in non-lame horses.
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| 8. |
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| 9. |
- Byström, Lars-Erik, et al.
(författare)
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Digital video for improved training and risk communication in occupational hygiene [Poster]
- 2005
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Ingår i: IOHA 6th International Conference. - Pilansberg, South Africa.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Video technology has been utilized for the production of training films focusing on occupational hygiene topics for at least two decades. These films have mainly been produced in a traditional way with some basic story told, illustrated with video pictures and accompanied by a speaker voice. The introduction video exposure monitoring technologies as PIMEX have made it possible to develop the use of video by adding additional information to the video picture about, at the same time occurring exposure to e.g. air contaminants. This technology has meant an important advance what concerns improved understanding of the link between occupational exposure and the situation in the work place and worker behaviour. The improved possibility to involve the worker and supervisors in the search for effective control measures is perhaps the most important characteristic. This technology is now used in several countries and the experiences from its use prompts for continued development and widened use. The development of video technology, especially digital video and the possibilities to do professional editing in standard computers implies a fantastic possibility and challenge for the occupational hygienist. Digital video cameras, computers with video editing as standard and possibilities to produce ready products on built in CD or DVD burners are now common products on the consumer market which implies that the price level has gone down drastically. With those tools is it therefore possible now to produce advanced reports and especially effective, visualized training materials. This way of using the technology is already in use in different countries for production of exposure study reports as CD-ROMs including text as well as video illustrations. At the Swedish Institute for Working Life has training videos using visualization methods as PIMEX been produced for many years. In recent year has this production been developed in many ways to make a wider and more effective distribution of knowledge possible? One example is the production of an extensive training material focusing on control of occupational exposure to dust. This product is also produced in html-code, which means that it can be used in most standard computers and that it is prepared for distribution on Internet. The duplication of such a product is not expensive and the possibility to distribute via Internet makes a wide knowledge spread possible. Other examples have focused on hazard control in wood industry and the organisation of a systematic work environment management system. The today available technology based on digital video and computer technology has made it possible for non-professional video producers to produce and distribute training material which are much more effective to get the message across. This possibility may be compared to the introduction of word processing technology which today makes it possible for any hygienist to write professionally looking reports. It is now time for occupational hygienists to utilize the new possibilities for production of effective training tools.
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| 10. |
- Egenvall, Agneta, et al.
(författare)
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Rein Tension in Transitions and Halts during Equestrian Dressage Training
- 2019
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Ingår i: Animals. - : MDPI AG. - 2076-2615. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Simple Summary In the equestrian dressage discipline, the transitions (changes) between gaits and into halts, occur often in riding sessions. Rein tension before, during and after the transitions between gaits, and the transitions into halts were studied. The vertical motion data for the horse's head and croup, and rein tension data were collected from six professional riders, each riding three of their own horses during normal training sessions. The horse training levels varied from basic to advanced. The activities during the sessions were categorised into gaits, transitions between gaits and into halts based on video evaluation. The transitions were categorised according to whether they had intermediate steps that were not characteristic of the preceding or the following gait. The rein tension just before the transition was strongly related to rein tension during the transitions. There was slightly lower tension during the upward transitions than during the downward transitions. There was no difference in rein tension depending on whether intermediate steps were present or not. The left rein tension was generally lower than the right rein tension. The rein tension associated with the transitions and halts varied substantially between riders and also the horses. This information is useful for trainers seeking to understand the rein tension patterns associated with transitions.Abstract In dressage, the performance of transitions between gaits and halts is an integral part of riding sessions. The study aimed to evaluate rein tension before, during and after the transitions between different gaits and the transitions into halts. The kinematic (inertial measurement units) data for the head and croup, and rein tension data, were collected (128 Hz) from six professional riders each riding three of their own horses, training levels varying from basic to advanced, during normal training sessions. The activities were categorised into gaits, halts and transitions based on video evaluation. The transitions were categorised as without (type 1) or with (type 2) intermediate steps that are not normally present in the gaits preceding or following the transition. The differences in the median rein tension before/during/after transitions, between the types and left/right reins were analysed in mixed models. The rein tension just before the transition was the strongest determinant of tension during the transition. The rein tension was slightly lower during upward transitions compared to downward transitions, reflecting the pattern of the preceding gait. Type 1 and 2 downward transitions were not different regarding rein tension. The left rein tension was lower than right rein tension. The rein tension associated with the transitions and halts varied substantially between riders and horses. The generally strong association of the gaits and their inherent biomechanics with rein tension should be taken into account when riding transitions and halts.
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