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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
Human Movement Science 41 (2015) 1–8
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Human Movement Science journal homepage: www.elsevier.com/locate/humov
Differences in rider movement pattern between different degrees of collection at the trot in high-level dressage horses ridden on a treadmill A. Byström a,⇑, L. Roepstroff a, K. Geser-von Peinen b, M.A. Weishaupt b, M. Rhodin c a
Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden Equine Department, Vetsuisse Faculty, University of Zurich, CH-8057 Zurich, Switzerland c Department of Clinical Sciences, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden b
a r t i c l e
i n f o
PsycINFO classification: 3720 Keywords: Collection Equestrian dressage Kinematics analysis
a b s t r a c t 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. Ó 2015 Elsevier B.V. All rights reserved.
⇑ Corresponding author. Tel.: +46 736 283908. E-mail address: [email protected] (A. Byström). http://dx.doi.org/10.1016/j.humov.2015.01.016 0167-9457/Ó 2015 Elsevier B.V. All rights reserved.
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A. Byström et al. / Human Movement Science 41 (2015) 1–8
1. Introduction 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 (Fédération Equestre Intenationale [FEI], 2011). The ability of the horse to perform collected gaits, in particular the piaffe and the passage, is crucial for high-level dressage performance (Holmström, Fredricson, & Drevemo, 1995). The collected gaits are created and shaped through the interplay between horse and rider. However, what that means in terms of rider kinematics has, to the authors’ knowledge, not yet been investigated. The rider’s position and movements in different gaits have been documented in several previous studies, by use of either camera recordings with optical markers (Byström, Rhodin, von Peinen, Weishaupt, & Roepstorff, 2009, 2010; Lovett, Hodson-Tole, & Nankervis, 2004; Schils, Greer, Stoner, & Kobluk, 1993; Symes & Ellis, 2009) or inertial sensor units fixed to the rider’s body (Münz, Eckardt, Heipertz-Hengst, Peham, & Witte, 2013; Münz, Eckardt, & Witte, 2014). Additionally, camera recordings and accelerometers have been used to study the coordination pattern between horse and rider during basic dressage (Lagarde, Kelso, Peham, & Licka, 2005; Peham, Licka, Kapaun, & Scheidl, 2001; Witte, Schobesberger, & Peham, 2009; Wolframm, Bosga, & Meulenbroek, 2013) and in endurance riding (Viry et al., 2013). One of the latter studies also investigated if differences in horse–rider coordination pattern between different riders were accompanied by changes in the horse’s movements (Lagarde et al., 2005). However, none of the studies has evaluated how changes in the rider’s movements influence the horse, and vice versa, within the same gait and horse–rider combination. Studies have shown that the horse’s movement pattern differs between free trot (unrestrained horse, loose reins) and collected trot (Rhodin, Gomez Alvarez, Byström, van Weeren, et al., 2009; Weishaupt et al., 2006), and between collected trot and passage (Weishaupt et al., 2009). These differences could potentially influence the rider’s movement pattern. However, since the equestrian literature states that riders should adjust their seat depending on the degree of collection that is being requested from the horse (von Dietze, 2005), changes may also be voluntarily adopted by the riders. It is therefore relevant to review any changes in the rider’s movement pattern both in relation to the movements of the horse, and to statements in equestrian texts, when trying to understand the interplay between the horse and rider in different degrees of collection. The aim of this study was to compare the movement pattern of high-level dressage riders between free trot, collected trot, and passage. For collected trot a range of three speeds was included, to enable differentiation between effects of speed and effects of the different forms of trot, i.e., free trot or passage compared to collected trot. 2. Material and methods 2.1. Experimental set-up This study was part of a larger experiment, described in detail elsewhere (Gómez Álvarez et al., 2006; Weishaupt et al., 2006). The experimental protocol was approved by the Animal Health and Welfare Commission of the canton of Zurich (188/2005; 26.01.2005). 2.2. Horses and riders Seven dressage horses actively competing at Grand Prix (n = 6) or FEI Intermediate (n = 1) level were included. The horses were of Warmblood breed (height mean ± SD 1.70 ± 0.07 m), equipped with their own fitted saddle, bridled with a normal snaffle bit and ridden by their usual riders (three men and four women). The riders had not been training together or with the same trainer prior to the study. 2.3. Kinematic measurements The experiment was conducted on a high-speed treadmill (Mustang 2200, Kagra AG) with an integrated force measuring system (Weishaupt et al., 2002). Horses and riders were measured at square
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stance, and at three different speeds in collected trot, in free trot (unrestrained horse, loose reins) and in passage (only the six Grand Prix horses), with the riders sitting at the trot. Passage and free trot was performed at the speed in which each horse and rider performed at ease. For collected trot the speeds were selected based on the previously published speed for this form of trot, 3.20 ± 0.28 m/s (mean ± SD; Clayton, 1994): For each horse, the three speeds ranged at least one SD (0.28 m/s) and were all below one SD from the mean (<3.48 m/s). For passage and collected trot a qualified dressage judge confirmed that the horse’s performance was satisfactory, otherwise the measurement was discarded and repeated. Spherical 19 mm reflective markers were placed on horse, rider, and saddle (locations are specified below). Marker positions were registered using twelve infrared cameras (ProReflex, Qualisys) and proprietary software (Q-Track, Qualisys), at a frame rate of 240 Hz for 3 horses and 140 Hz for 4 horses. Each condition was recorded once for each horse and each recording lasted 15 s. The laboratory coordinate system was oriented with the X-axis horizontal and positive in the horse’s direction of motion, the Y-axis horizontal and positive to the left, and the Z-axis vertical and positive upwards. 2.4. Data analysis The raw X-, Y- and Z-coordinates were analyzed using custom written code in Matlab (Mathworks). The rider’s upper body and pelvis were subjected to rigid body analysis, as described by Söderkvist and Wedin (1993). Rotations around the X-, Y- and Z-axes were thereby described as roll, pitch and yaw angles, respectively. Marker locations were; Rider’s pelvis: sacrum and the left and right major trochanters of femur; Rider’s upper body: sacrum, shoulder joints and the spinous process of the seventh cervical vertebrae (C7). Segment rotations for the rider’s upper body were calculated in relation to the rider’s pelvis. Angular changes were assigned positive values for clockwise rotation viewed in the direction of the respective axis. Only pitch rotations were retained for further analysis, because in trot rider roll and yaw rotations have comparably lower range and larger between-rider variability (Byström et al., 2009). In the results section, positive pitch rotation will be termed cranial. To define the rider’s position in relation to the horse, distances between horse and rider markers were calculated as follows: (1) longitudinal distance from rider’s C7 to the spinous process of the third lumbar vertebrae (L3) of the horse; (2) longitudinal, and (3) vertical distances from rider’s seat (a mean of the left and right trochanters) to L3 of the horse; (4) vertical distances from rider’s knee to L3 of the horse; (5) longitudinal distance from the toe of the rider’s boot to L3 of the horse. Data for each variable was split into strides based on left hind limb first contact times from the treadmill force measuring system, and normalized to 101 points (0–100%). Stride mean value and range were determined. Mean and SD were then calculated over available strides for each horse/rider. Time of transition (ToT), defined as minimum or maximum value time of occurrence in percent of stride time, was compared between the vertical displacement of a marker placed at the spinous process of L5 of the horse and each of the above listed variables, except distances 4 and 5 (because the curve shapes precluded detection of relevant extreme points). 2.5. Statistical analysis The mixed procedure in SAS (SAS Institute) was used to create multivariable models with horse, form of trot (collected trot, free trot or passage) and speed as independent variables, and stride mean, stride range and ToTs (except distances 4–5) for each rider variable as the dependent variable. Bilateral variables were averaged for each rider. Speed was modeled as a linear effect, because even if some variables may correlate to speed in a quadratic manner, the function will be close to linear within our narrow speed range. The interaction between condition and speed was included in the model if significant (P < .05). Horse was modeled as a random factor. Interactions between horse and speed, and horse and condition were included if this improved the Akaike information criteria. Passage and free trot were analyzed separately. Model parameter estimates were used to assess significant differences between collected trot, and passage and free trot, respectively, as well significant effects of speed in
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collected trot (using the passage model). If the interaction between speed and condition was significant, the difference between conditions was estimated at group mean speed for passage (1.84 m/s) or free trot (3.15 m/s), respectively.
3. Results Collected trot was recorded in speeds ranging from 2.74 to 3.29 m/s; the speed range recorded for each horse was 0.39 ± 0.07 m/s (group mean ± SD). Group mean speed for free trot was 3.15 ± 0.15 m/s and for passage 1.84 ± 0.38 m/s. The changes in the rider’s position with the respective conditions, or tasks, are illustrated in Fig. 1, with the intention to help the reader visualize the results reported below. In collected trot, speed had a significant influence on several variables (Table 1). With higher speed the rider’s pelvis became more caudally rotated, while the upper body became more cranially rotated in relation to the pelvis, indicating increased flexion of the rider’s lumbar back. Further, the mean vertical distance between the rider’s seat and L3 of the horse increased slightly, while the same longitudinal distance became smaller. The mean vertical distance between the rider’s knees and L3 of the horse also decreased with increasing speed. The ranges for the longitudinal distance between the rider’s seat and neck, respectively, and L3 of the horse both decreased as speed increased, while the range for the longitudinal distance between the rider’s toes and L3 of the horse tended to be lower (P = .062). With regards to timing (Table 2), the difference in ToT between the vertical displacement of L5 of the horse and the longitudinal distance between the rider’s neck and L3 of the horse was larger at higher speed, both at first contact and at midstance. At the same time the difference in ToT tended to decrease at first contact for pitch rotation of the rider’s pelvis (P = .088), and at midstance for the vertical distance between the rider’s seat and L3 of the horse (P = .090). In passage, the rider’s pelvis tended to be more caudally rotated (P = .067), and the rider’s upper body was more cranially rotated in relation to the pelvis, compared to collected trot (Table 1 and Fig. 1). The longitudinal distance between the rider’s seat and L3 of the horse tended to be smaller (P = .094). The ranges for the vertical distance between the rider’s seat and knees, respectively, and L3 of the horse were larger, while the mean vertical distance between the rider’s knees and L3 of the horse was smaller. With regards to timing (Table 2), differences in ToT relative to the vertical displacement of L5 of the horse was lower for pitch rotation of the rider’s pelvis at first contact, and for
(a)
(b)
(c)
Fig. 1. Illustration of changes in stride mean position of the rider’s upper body, pelvis, knees and feet (a) at higher (grey line) compared to lower speed (black interrupted line) in collected trot, (b) in passage (grey line) compared to collected trot (black interrupted line) and (c) in trot on loose reins (grey line) compared to collected trot (black interrupted line).
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Table 1 Changes for 1 m/s speed increase in collected trot, for passage compared to collected trot estimated at group mean speed for passage (1.84 m/s), and for free trot (loose reins) compared to collected trot estimated at group mean speed for free trot (3.15 m/s), in high-level dressage horses (n = 7) ridden on a treadmill. Table values represent estimate ± SE for significant differences (P < .05), except values in brackets for which P was <.1 (results with higher P-value are not shown). Stride Rider pelvis
Pitch (°)
Rider upper body
Pitch (°)
Rider seat – horse L3
Long. distance (mm) Vert. distance (mm)
Rider neck – horse L3
Long. distance (mm)
Rider knee – horse L3
Vert. distance (mm)
Rider toe – horse L3
Long. distance (mm)
+1 m/s in collected tr.
Mean Range Mean Range Mean
4.6 ± 1.5
Range Mean
15 ± 5 7±2
4.2 ± 1.0 17 ± 5
Range Mean Range Mean
( 6.0 ± 2.6) 5.8 ± 1.7
Free trot vs. collected tr. 5.0 ± 1.0 1.1 ± 0.3 2.3 ± 0.9
( 10 ± 6)
23 ± 7 30 ± 10 10 ± 4 14 ± 4
Range Mean Range
Passage vs. collected tr.
20 ± 8 26 ± 9
( 5.2 ± 2.3)
( 26 ± 13)
tr. = trot; long. = longitudinal; vert. = vertical.
Table 2 Changes in phase relative to the vertical displacement of the fifth lumbar vertebra of the horse, determined as lag time between minimum or maximum value times of occurrence (% stride), at first contact (fc) and at midstance (ms). Table values represent estimates ± SE for the effects of 1 m/s speed increase in collected trot, passage compared to collected trot estimated at group mean speed for passage (1.84 m/s), and free trot (loose reins) compared to collected trot estimated at group mean speed for free trot (3.15 m/s), measured in high-level dressage horses (n = 7) ridden on a treadmill. All listed differences were significant (P < .05), except values in brackets for which P was <.1 (results with higher P-value are not shown).
Rider pelvis
Pitch
Rider upper body
Pitch
Rider seat – horse L3
Long. distance Vert. distance
Rider neck – horse L3
Long. distance
fc ms fc ms fc ms fc ms fc ms
+1 m/s in collected tr.
Passage vs. collected tr.
( 1.3 ± 0.7)
4.4 ± 1.1 ( 4.0 ± 1.7)
Free trot vs. collected tr.
14.9 ± 4.4 6.6 ± 1.9 ( 5.5 ± 3.0) 4.8 ± 1.7 6.9 ± 2.1
( 9.4 ± 4.2)
0.7 ± 0.3 3.6 ± 0.9 1.6 ± 0.7
(4.4 ± 2.0)
tr. = trot; long. = longitudinal; vert. = vertical.
the longitudinal distance between the rider’s seat and L3 of the horse both at first contact and at midstance, compared to collected trot. The ToT difference also tended to be lower at midstance for both pitch rotation of the rider’s pelvis (P = .076) and the longitudinal distance between the rider’s seat and L3 of the horse (P = .088). However, the ToT difference for the longitudinal distance between the rider’s neck and L3 of the horse tended to be larger at midstance (P = .051).
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In free trot, the rider’s the pelvis was more cranially rotated, the upper body was more caudally rotated in relation to the pelvis, and longitudinal distance from the rider’s neck to L3 of the horse was larger, compared to collected trot (Table 1 and Fig. 1). In addition, stride range was smaller for pitch rotation of the rider’s pelvis, and tended to be smaller for the vertical distance between the rider’s knees and L3 of the horse (P = .067). With regards to timing (Table 2), the difference in ToT relative to the vertical displacement of L5 of the horse was larger for the longitudinal distance between the rider’s neck and L3 of the horse at first contact, as well as for the vertical distance between the rider’s seat and L3 of the horse both at first contact and at midstance, compared to collected trot.
4. Discussion In this study, more or less collection at the trot was found to be accompanied by several changes in the rider’s movements. Some of these changes may have been passively induced by changes in the horse’s movement pattern. Two studies comparing the movement pattern of the (same) horses between free and collected trot found that the free trot was characterized by less vertical excursion of the withers, less extension of the hind fetlock at midstance, and slower flexion and protraction of the hind limb after lift-off (Rhodin et al., 2009), as well as a shorter suspension duration and lower front limb peak vertical force (Weishaupt et al., 2006). Decreased acceleration and vertical excursion of the horse’s trunk are plausible causes for the lower range of pitch rotation of the rider’s pelvis and the tendency towards less vertical displacement of the rider’s knees observed in free trot (Table 1). Changes in the rider’s body position, however, do not seem to correlate with the horse’s movements: The forward leaning position of the rider’s body in free trot (Fig. 1) is hard to explain from the above mentioned changes in the horse’s movement pattern. Further, at the passage the speed was low and the vertical displacement of both horse (Weishaupt et al., 2009) and rider (Table 1) was increased, whereas the horse’s vertical excursion is known to decrease with increasing trotting speed (Robert, Valette, & Denoix, 2001); yet the rider’s lumbar back was more flexed both at the passage and at higher speed in collected trot (Fig. 1). These different body positions are therefore more likely to be voluntarily adopted by the riders, and an explanation for them must thus be sought in the equestrian literature. The riders’ body position in free trot corresponds well to descriptions of the so called light seat, in which the rider should bend his upper body forward from the hips and transfer weight from the seat bones to the thighs, knees and stirrups (German National Equestrian Federation [FN], 1997). The light seat enables the rider to adjust particularly well to changes in the horse’s balance and pace, and is useful for example when riding out (FN, 1997). This seat thus seems a good choice for the free trot, for which the riders were asked to minimize their influence. Collection, on the other hand, is induced by active rider interventions; collection is achieved through a fine tuning of the driving and restraining aids (Decarpentry, 1971; FEI, 2011; von Dietze, 2005). In collecting the horse, the so called half-halt is of central importance (Decarpentry, 1971; FEI, 2011; FN, 1997; von Dietze, 2005). In a half-halt the horse should step further forward underneath its body and carry more weight on the hind limbs, without losing impulsion (FN, 1997). The primary aid for the half-halt is the seat, or weight: The rider should momentarily sit deeper into the saddle and place increased weight on the seat bones by increasing the basic tension in the lower back and abdominal muscles (Decarpentry, 1971; FN, 1997; von Dietze, 2005). If such increased muscle tension is to have the described effect, it must likely be applied to counteract the lumbar back extension and cranial rotation of the pelvis that occurs as the rider moves downwards relative to the horse during the first half of stance (Byström et al., 2009). That, in turn, would result in changes in the rider’s body position similar to those observed for passage in the current study (Fig. 1). The riders’ use of frequent half-halts to maintain their horses in passage is therefore a plausible explanation for those changes. A half-halt comprises the application of a pressure that is released upon the desired response, i.e., increased collection, and can therefore be considered a form of negative reinforcement. When using negative reinforcement in the training of horses, it is very important that the reinforcing stimulus is removed immediately when the desired goal is reached (Mills, 1998), and the riders in this study seem to have followed that advice. Because collection comprises a decrease in the horse’s stride
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length, a lower speed within the same gait can be assumed to represent a higher degree of collection, if performed by high-level dressage horses. Yet the riders’ lumbar backs became more extended with decreasing speed in collected trot (Fig. 1). This indicates that these high-level horses were able, and consequently allowed, to perform the slow collected trot without the support from frequent half-halts. This difference between a slow collected trot and passage is explainable from the fact that the passage represents a higher degree of collection compared to collected trot (FEI, 2011). However, the results do suggest that the riders needed to use more active leg aids at a slower collected trot: the rider’s knees were lowered and the range of longitudinal displacement of the rider’s toes tended to increase as speed decreased (Fig. 1 and Table 1). Both pitch rotation of the rider’s pelvis and the longitudinal displacement of the rider’s seat were significantly less phase-shifted in relation to the horse in passage compared to collected trot, and in collected trot the phase-shift for the longitudinal displacement of the rider’s neck decreased significantly with decreasing speed, i.e., increased collection. In free trot, on the other hand, the phase-shift between rider and horse increased for the vertical displacement of the rider’s seat and the longitudinal displacement of the rider’s neck (Table 2). It has previous been found that an expert rider’s movements are less phase-shifted in relation to the horse compared to a novice rider riding the same horse (Lagarde et al., 2005). It has also been shown that an expert rider has a more specific effect (i.e., uniform across horses) on the horse’s head movements compared to a novice (Schöllhorn, Peham, Licka, & Scheidl, 2006), and that the regularity of the horse’s movements increases when ridden by an expert rider, both compared to a novice rider (Lagarde et al., 2005) and compared to trot in hand (Peham, Licka, Schobesberger, & Meschan, 2004). Taken together, these results thus suggest that a more active and purposive influence from the rider correlates with a decrease in phase-shift between horse and rider. 5. Conclusion Even though the basic movement pattern of the rider has been shown to be closely related to the horse’s movements, the results of the current study suggest that differences in the rider’s body position and movement synchronicity relative to the horse observed between different degrees of collection at the trot are predominantly related to active rider intervention, at least among high-level dressage riders. The findings give a scientific insight into horse–rider interaction, providing some clues to how different gait patterns are induced and maintained by the rider. Conflict of interest None of the authors of this paper has a financial or personal relationship with other people or organisations that could inappropriately influence or bias the content of the paper. Acknowledgements This study was supported by grants from the Swedish Foundation for Equine Research, Sveland Insurance Company, Ulla Håkanson and the Stiftung Forschung für das Pferd, Zurich, Switzerland. The authors wish to thank Sören Johansson, Nina Waldern and Thomas Wiestner for excellent technical assistance and the all riders for their participation. References Byström, A., Rhodin, M., von Peinen, K., Weishaupt, M. A., & Roepstorff, L. (2009). Basic kinematics of the saddle and rider in high-level dressage horses trotting on a treadmill. Equine Veterinary Journal, 41, 280–284. Byström, A., Rhodin, M., von Peinen, K., Weishaupt, M. A., & Roepstorff, L. (2010). Kinematics of saddle and rider in high-level dressage horses performing collected walk on a treadmill. Equine Veterinary Journal, 42, 340–345. Clayton, H. M. (1994). Comparison of the stride kinematics of the collected, working, medium and extended trot in horses. Equine Veterinary Journal, 26, 230–234. Decarpentry (1971). Academic equitation: A preparation for international dressage tests. London: J.A. Allen. German National Equestrian Federation [FN]. (1997). The principles of riding (Completely rev. ed.). Buckingham: Kenilworth.
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Fédération Equestre Intenationale [FEI]. (2011). Dressage rules (24th ed.). Switzerland: Lusanne. Gómez Álvarez, C. B., Rhodin, M., Bobbert, M. F., Meyer, H., Weishaupt, M. A., Johnston, C., et al (2006). The effect of head and neck position on the thoracolumbar kinematics in the unridden horse. Equine Veterinary Journal, 36(Suppl.), 445–451. Holmström, M., Fredricson, I., & Drevemo, S. (1995). Biokinematic effects of collection on the trotting gaits in the elite dressage horse. Equine Veterinary Journal, 27, 281–287. Lagarde, J., Kelso, J. A., Peham, C., & Licka, T. (2005). Coordination dynamics of the horse–rider system. Journal of Motor Behaviour, 37, 418–424. Lovett, T., Hodson-Tole, E., & Nankervis, K. (2004). A preliminary investigation of rider position during walk, trot and canter. Equine and Comparative Exercise Physiology, 2, 71–76. Mills, D. S. (1998). Applying learning theory to the management of the horse: the difference between getting it right and getting it wrong. Equine Veterinary Journal, 30, 44–48. Münz, A., Eckardt, F., Heipertz-Hengst, C., Peham, C., & Witte, K. (2013). A preliminary study of an inertial sensor-based method for the assessment of human pelvis kinematics in dressage riding. Journal of Equine Veterinary Science, 33, 950–955. Münz, A., Eckardt, F., & Witte, K. (2014). Horse–rider interaction in dressage riding. Human Movement Science, 33, 227–237. Peham, C., Licka, T., Kapaun, M., & Scheidl, M. (2001). A new method to quantify harmony of the horse–rider system in dressage. Sports Engineering, 4, 95–101. Peham, C., Licka, T., Schobesberger, H., & Meschan, E. (2004). Influence of the rider on the variability of the equine gait. Human Movement Science, 23, 663–671. Rhodin, M., Gomez Alvarez, C. B., Byström, A., Johnston, C., van Weeren, P. R., et al (2009). The effect of different head and neck positions on the caudal back and hindlimb kinematics in the elite dressage horse at trot. Equine Veterinary Journal, 41, 274–279. Robert, C., Valette, J. P., & Denoix, J. M. (2001). The effects of treadmill inclination and speed on the activity of three trunk muscles in the trotting horse. Equine Veterinary Journal, 33, 466–472. Schils, S. J., Greer, N. L., Stoner, L. J., & Kobluk, C. N. (1993). Kinematic analysis of the equestrian – Walk, posting trot and sitting trot. Human Movement Science, 12, 693–712. Schöllhorn, W. I., Peham, C., Licka, T., & Scheidl, M. (2006). A pattern recognition approach for the quantification of horse and rider interactions. Equine Veterinary Journal, 36(Suppl.), 400–405. Söderkvist, I., & Wedin, P. A. (1993). Determining the movements of the skeleton using well-configured markers. Journal of Biomechanics, 26, 1473–1477. Symes, D., & Ellis, R. (2009). A preliminary study into rider asymmetry within equitation. The Veterinary Journal, 181, 34–37. Viry, S., Sleimen-Malkoun, R., Temprado, J. J., Frances, J. P., Berton, E., Laurent, M., et al (2013). Patterns of horse–rider coordination during endurance race: A dynamical system approach. PLoS ONE, 8, 22. von Dietze, S. (2005). Balance in movement: How to achieve the perfect seat. London: J.A. Allen. Weishaupt, M. A., Byström, A., von Peinen, K., Wiestner, T., Meyers, H., Waldern, N., et al (2009). Kinetics and kinematics of the passage. Equine Veterinary Journal, 41, 263–267. Weishaupt, M. A., Hogg, H. P., Wiestner, T., Denoth, J., Stussi, E., & Auer, J. A. (2002). Instrumented treadmill for measuring vertical ground reaction forces in horses. American Journal of Veterinary Research, 63, 520–527. Weishaupt, M. A., Wiestner, T., von Peinen, K., Waldern, N., Roepstorff, L., van Weeren, R., et al (2006). 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. Equine Veterinary Journal, 36(Suppl.), 387–392. Witte, K., Schobesberger, H., & Peham, C. (2009). Motion pattern analysis of gait in horseback riding by means of Principal Component Analysis. Human Movement Science, 28, 394–405. Wolframm, I. A., Bosga, J., & Meulenbroek, R. G. J. (2013). Coordination dynamics in horse–rider dyads. Human Movement Science, 32, 157–170.
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Human Movement Science journal homepage: www.elsevier.com/locate/humov
Differences in rider movement pattern between different degrees of collection at the trot in high-level dressage horses ridden on a treadmill A. Byström a,⇑, L. Roepstroff a, K. Geser-von Peinen b, M.A. Weishaupt b, M. Rhodin c a
Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden Equine Department, Vetsuisse Faculty, University of Zurich, CH-8057 Zurich, Switzerland c Department of Clinical Sciences, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden b
a r t i c l e
i n f o
PsycINFO classification: 3720 Keywords: Collection Equestrian dressage Kinematics analysis
a b s t r a c t 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. Ó 2015 Elsevier B.V. All rights reserved.
⇑ Corresponding author. Tel.: +46 736 283908. E-mail address: [email protected] (A. Byström). http://dx.doi.org/10.1016/j.humov.2015.01.016 0167-9457/Ó 2015 Elsevier B.V. All rights reserved.
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1. Introduction 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 (Fédération Equestre Intenationale [FEI], 2011). The ability of the horse to perform collected gaits, in particular the piaffe and the passage, is crucial for high-level dressage performance (Holmström, Fredricson, & Drevemo, 1995). The collected gaits are created and shaped through the interplay between horse and rider. However, what that means in terms of rider kinematics has, to the authors’ knowledge, not yet been investigated. The rider’s position and movements in different gaits have been documented in several previous studies, by use of either camera recordings with optical markers (Byström, Rhodin, von Peinen, Weishaupt, & Roepstorff, 2009, 2010; Lovett, Hodson-Tole, & Nankervis, 2004; Schils, Greer, Stoner, & Kobluk, 1993; Symes & Ellis, 2009) or inertial sensor units fixed to the rider’s body (Münz, Eckardt, Heipertz-Hengst, Peham, & Witte, 2013; Münz, Eckardt, & Witte, 2014). Additionally, camera recordings and accelerometers have been used to study the coordination pattern between horse and rider during basic dressage (Lagarde, Kelso, Peham, & Licka, 2005; Peham, Licka, Kapaun, & Scheidl, 2001; Witte, Schobesberger, & Peham, 2009; Wolframm, Bosga, & Meulenbroek, 2013) and in endurance riding (Viry et al., 2013). One of the latter studies also investigated if differences in horse–rider coordination pattern between different riders were accompanied by changes in the horse’s movements (Lagarde et al., 2005). However, none of the studies has evaluated how changes in the rider’s movements influence the horse, and vice versa, within the same gait and horse–rider combination. Studies have shown that the horse’s movement pattern differs between free trot (unrestrained horse, loose reins) and collected trot (Rhodin, Gomez Alvarez, Byström, van Weeren, et al., 2009; Weishaupt et al., 2006), and between collected trot and passage (Weishaupt et al., 2009). These differences could potentially influence the rider’s movement pattern. However, since the equestrian literature states that riders should adjust their seat depending on the degree of collection that is being requested from the horse (von Dietze, 2005), changes may also be voluntarily adopted by the riders. It is therefore relevant to review any changes in the rider’s movement pattern both in relation to the movements of the horse, and to statements in equestrian texts, when trying to understand the interplay between the horse and rider in different degrees of collection. The aim of this study was to compare the movement pattern of high-level dressage riders between free trot, collected trot, and passage. For collected trot a range of three speeds was included, to enable differentiation between effects of speed and effects of the different forms of trot, i.e., free trot or passage compared to collected trot. 2. Material and methods 2.1. Experimental set-up This study was part of a larger experiment, described in detail elsewhere (Gómez Álvarez et al., 2006; Weishaupt et al., 2006). The experimental protocol was approved by the Animal Health and Welfare Commission of the canton of Zurich (188/2005; 26.01.2005). 2.2. Horses and riders Seven dressage horses actively competing at Grand Prix (n = 6) or FEI Intermediate (n = 1) level were included. The horses were of Warmblood breed (height mean ± SD 1.70 ± 0.07 m), equipped with their own fitted saddle, bridled with a normal snaffle bit and ridden by their usual riders (three men and four women). The riders had not been training together or with the same trainer prior to the study. 2.3. Kinematic measurements The experiment was conducted on a high-speed treadmill (Mustang 2200, Kagra AG) with an integrated force measuring system (Weishaupt et al., 2002). Horses and riders were measured at square
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stance, and at three different speeds in collected trot, in free trot (unrestrained horse, loose reins) and in passage (only the six Grand Prix horses), with the riders sitting at the trot. Passage and free trot was performed at the speed in which each horse and rider performed at ease. For collected trot the speeds were selected based on the previously published speed for this form of trot, 3.20 ± 0.28 m/s (mean ± SD; Clayton, 1994): For each horse, the three speeds ranged at least one SD (0.28 m/s) and were all below one SD from the mean (<3.48 m/s). For passage and collected trot a qualified dressage judge confirmed that the horse’s performance was satisfactory, otherwise the measurement was discarded and repeated. Spherical 19 mm reflective markers were placed on horse, rider, and saddle (locations are specified below). Marker positions were registered using twelve infrared cameras (ProReflex, Qualisys) and proprietary software (Q-Track, Qualisys), at a frame rate of 240 Hz for 3 horses and 140 Hz for 4 horses. Each condition was recorded once for each horse and each recording lasted 15 s. The laboratory coordinate system was oriented with the X-axis horizontal and positive in the horse’s direction of motion, the Y-axis horizontal and positive to the left, and the Z-axis vertical and positive upwards. 2.4. Data analysis The raw X-, Y- and Z-coordinates were analyzed using custom written code in Matlab (Mathworks). The rider’s upper body and pelvis were subjected to rigid body analysis, as described by Söderkvist and Wedin (1993). Rotations around the X-, Y- and Z-axes were thereby described as roll, pitch and yaw angles, respectively. Marker locations were; Rider’s pelvis: sacrum and the left and right major trochanters of femur; Rider’s upper body: sacrum, shoulder joints and the spinous process of the seventh cervical vertebrae (C7). Segment rotations for the rider’s upper body were calculated in relation to the rider’s pelvis. Angular changes were assigned positive values for clockwise rotation viewed in the direction of the respective axis. Only pitch rotations were retained for further analysis, because in trot rider roll and yaw rotations have comparably lower range and larger between-rider variability (Byström et al., 2009). In the results section, positive pitch rotation will be termed cranial. To define the rider’s position in relation to the horse, distances between horse and rider markers were calculated as follows: (1) longitudinal distance from rider’s C7 to the spinous process of the third lumbar vertebrae (L3) of the horse; (2) longitudinal, and (3) vertical distances from rider’s seat (a mean of the left and right trochanters) to L3 of the horse; (4) vertical distances from rider’s knee to L3 of the horse; (5) longitudinal distance from the toe of the rider’s boot to L3 of the horse. Data for each variable was split into strides based on left hind limb first contact times from the treadmill force measuring system, and normalized to 101 points (0–100%). Stride mean value and range were determined. Mean and SD were then calculated over available strides for each horse/rider. Time of transition (ToT), defined as minimum or maximum value time of occurrence in percent of stride time, was compared between the vertical displacement of a marker placed at the spinous process of L5 of the horse and each of the above listed variables, except distances 4 and 5 (because the curve shapes precluded detection of relevant extreme points). 2.5. Statistical analysis The mixed procedure in SAS (SAS Institute) was used to create multivariable models with horse, form of trot (collected trot, free trot or passage) and speed as independent variables, and stride mean, stride range and ToTs (except distances 4–5) for each rider variable as the dependent variable. Bilateral variables were averaged for each rider. Speed was modeled as a linear effect, because even if some variables may correlate to speed in a quadratic manner, the function will be close to linear within our narrow speed range. The interaction between condition and speed was included in the model if significant (P < .05). Horse was modeled as a random factor. Interactions between horse and speed, and horse and condition were included if this improved the Akaike information criteria. Passage and free trot were analyzed separately. Model parameter estimates were used to assess significant differences between collected trot, and passage and free trot, respectively, as well significant effects of speed in
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collected trot (using the passage model). If the interaction between speed and condition was significant, the difference between conditions was estimated at group mean speed for passage (1.84 m/s) or free trot (3.15 m/s), respectively.
3. Results Collected trot was recorded in speeds ranging from 2.74 to 3.29 m/s; the speed range recorded for each horse was 0.39 ± 0.07 m/s (group mean ± SD). Group mean speed for free trot was 3.15 ± 0.15 m/s and for passage 1.84 ± 0.38 m/s. The changes in the rider’s position with the respective conditions, or tasks, are illustrated in Fig. 1, with the intention to help the reader visualize the results reported below. In collected trot, speed had a significant influence on several variables (Table 1). With higher speed the rider’s pelvis became more caudally rotated, while the upper body became more cranially rotated in relation to the pelvis, indicating increased flexion of the rider’s lumbar back. Further, the mean vertical distance between the rider’s seat and L3 of the horse increased slightly, while the same longitudinal distance became smaller. The mean vertical distance between the rider’s knees and L3 of the horse also decreased with increasing speed. The ranges for the longitudinal distance between the rider’s seat and neck, respectively, and L3 of the horse both decreased as speed increased, while the range for the longitudinal distance between the rider’s toes and L3 of the horse tended to be lower (P = .062). With regards to timing (Table 2), the difference in ToT between the vertical displacement of L5 of the horse and the longitudinal distance between the rider’s neck and L3 of the horse was larger at higher speed, both at first contact and at midstance. At the same time the difference in ToT tended to decrease at first contact for pitch rotation of the rider’s pelvis (P = .088), and at midstance for the vertical distance between the rider’s seat and L3 of the horse (P = .090). In passage, the rider’s pelvis tended to be more caudally rotated (P = .067), and the rider’s upper body was more cranially rotated in relation to the pelvis, compared to collected trot (Table 1 and Fig. 1). The longitudinal distance between the rider’s seat and L3 of the horse tended to be smaller (P = .094). The ranges for the vertical distance between the rider’s seat and knees, respectively, and L3 of the horse were larger, while the mean vertical distance between the rider’s knees and L3 of the horse was smaller. With regards to timing (Table 2), differences in ToT relative to the vertical displacement of L5 of the horse was lower for pitch rotation of the rider’s pelvis at first contact, and for
(a)
(b)
(c)
Fig. 1. Illustration of changes in stride mean position of the rider’s upper body, pelvis, knees and feet (a) at higher (grey line) compared to lower speed (black interrupted line) in collected trot, (b) in passage (grey line) compared to collected trot (black interrupted line) and (c) in trot on loose reins (grey line) compared to collected trot (black interrupted line).
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Table 1 Changes for 1 m/s speed increase in collected trot, for passage compared to collected trot estimated at group mean speed for passage (1.84 m/s), and for free trot (loose reins) compared to collected trot estimated at group mean speed for free trot (3.15 m/s), in high-level dressage horses (n = 7) ridden on a treadmill. Table values represent estimate ± SE for significant differences (P < .05), except values in brackets for which P was <.1 (results with higher P-value are not shown). Stride Rider pelvis
Pitch (°)
Rider upper body
Pitch (°)
Rider seat – horse L3
Long. distance (mm) Vert. distance (mm)
Rider neck – horse L3
Long. distance (mm)
Rider knee – horse L3
Vert. distance (mm)
Rider toe – horse L3
Long. distance (mm)
+1 m/s in collected tr.
Mean Range Mean Range Mean
4.6 ± 1.5
Range Mean
15 ± 5 7±2
4.2 ± 1.0 17 ± 5
Range Mean Range Mean
( 6.0 ± 2.6) 5.8 ± 1.7
Free trot vs. collected tr. 5.0 ± 1.0 1.1 ± 0.3 2.3 ± 0.9
( 10 ± 6)
23 ± 7 30 ± 10 10 ± 4 14 ± 4
Range Mean Range
Passage vs. collected tr.
20 ± 8 26 ± 9
( 5.2 ± 2.3)
( 26 ± 13)
tr. = trot; long. = longitudinal; vert. = vertical.
Table 2 Changes in phase relative to the vertical displacement of the fifth lumbar vertebra of the horse, determined as lag time between minimum or maximum value times of occurrence (% stride), at first contact (fc) and at midstance (ms). Table values represent estimates ± SE for the effects of 1 m/s speed increase in collected trot, passage compared to collected trot estimated at group mean speed for passage (1.84 m/s), and free trot (loose reins) compared to collected trot estimated at group mean speed for free trot (3.15 m/s), measured in high-level dressage horses (n = 7) ridden on a treadmill. All listed differences were significant (P < .05), except values in brackets for which P was <.1 (results with higher P-value are not shown).
Rider pelvis
Pitch
Rider upper body
Pitch
Rider seat – horse L3
Long. distance Vert. distance
Rider neck – horse L3
Long. distance
fc ms fc ms fc ms fc ms fc ms
+1 m/s in collected tr.
Passage vs. collected tr.
( 1.3 ± 0.7)
4.4 ± 1.1 ( 4.0 ± 1.7)
Free trot vs. collected tr.
14.9 ± 4.4 6.6 ± 1.9 ( 5.5 ± 3.0) 4.8 ± 1.7 6.9 ± 2.1
( 9.4 ± 4.2)
0.7 ± 0.3 3.6 ± 0.9 1.6 ± 0.7
(4.4 ± 2.0)
tr. = trot; long. = longitudinal; vert. = vertical.
the longitudinal distance between the rider’s seat and L3 of the horse both at first contact and at midstance, compared to collected trot. The ToT difference also tended to be lower at midstance for both pitch rotation of the rider’s pelvis (P = .076) and the longitudinal distance between the rider’s seat and L3 of the horse (P = .088). However, the ToT difference for the longitudinal distance between the rider’s neck and L3 of the horse tended to be larger at midstance (P = .051).
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In free trot, the rider’s the pelvis was more cranially rotated, the upper body was more caudally rotated in relation to the pelvis, and longitudinal distance from the rider’s neck to L3 of the horse was larger, compared to collected trot (Table 1 and Fig. 1). In addition, stride range was smaller for pitch rotation of the rider’s pelvis, and tended to be smaller for the vertical distance between the rider’s knees and L3 of the horse (P = .067). With regards to timing (Table 2), the difference in ToT relative to the vertical displacement of L5 of the horse was larger for the longitudinal distance between the rider’s neck and L3 of the horse at first contact, as well as for the vertical distance between the rider’s seat and L3 of the horse both at first contact and at midstance, compared to collected trot.
4. Discussion In this study, more or less collection at the trot was found to be accompanied by several changes in the rider’s movements. Some of these changes may have been passively induced by changes in the horse’s movement pattern. Two studies comparing the movement pattern of the (same) horses between free and collected trot found that the free trot was characterized by less vertical excursion of the withers, less extension of the hind fetlock at midstance, and slower flexion and protraction of the hind limb after lift-off (Rhodin et al., 2009), as well as a shorter suspension duration and lower front limb peak vertical force (Weishaupt et al., 2006). Decreased acceleration and vertical excursion of the horse’s trunk are plausible causes for the lower range of pitch rotation of the rider’s pelvis and the tendency towards less vertical displacement of the rider’s knees observed in free trot (Table 1). Changes in the rider’s body position, however, do not seem to correlate with the horse’s movements: The forward leaning position of the rider’s body in free trot (Fig. 1) is hard to explain from the above mentioned changes in the horse’s movement pattern. Further, at the passage the speed was low and the vertical displacement of both horse (Weishaupt et al., 2009) and rider (Table 1) was increased, whereas the horse’s vertical excursion is known to decrease with increasing trotting speed (Robert, Valette, & Denoix, 2001); yet the rider’s lumbar back was more flexed both at the passage and at higher speed in collected trot (Fig. 1). These different body positions are therefore more likely to be voluntarily adopted by the riders, and an explanation for them must thus be sought in the equestrian literature. The riders’ body position in free trot corresponds well to descriptions of the so called light seat, in which the rider should bend his upper body forward from the hips and transfer weight from the seat bones to the thighs, knees and stirrups (German National Equestrian Federation [FN], 1997). The light seat enables the rider to adjust particularly well to changes in the horse’s balance and pace, and is useful for example when riding out (FN, 1997). This seat thus seems a good choice for the free trot, for which the riders were asked to minimize their influence. Collection, on the other hand, is induced by active rider interventions; collection is achieved through a fine tuning of the driving and restraining aids (Decarpentry, 1971; FEI, 2011; von Dietze, 2005). In collecting the horse, the so called half-halt is of central importance (Decarpentry, 1971; FEI, 2011; FN, 1997; von Dietze, 2005). In a half-halt the horse should step further forward underneath its body and carry more weight on the hind limbs, without losing impulsion (FN, 1997). The primary aid for the half-halt is the seat, or weight: The rider should momentarily sit deeper into the saddle and place increased weight on the seat bones by increasing the basic tension in the lower back and abdominal muscles (Decarpentry, 1971; FN, 1997; von Dietze, 2005). If such increased muscle tension is to have the described effect, it must likely be applied to counteract the lumbar back extension and cranial rotation of the pelvis that occurs as the rider moves downwards relative to the horse during the first half of stance (Byström et al., 2009). That, in turn, would result in changes in the rider’s body position similar to those observed for passage in the current study (Fig. 1). The riders’ use of frequent half-halts to maintain their horses in passage is therefore a plausible explanation for those changes. A half-halt comprises the application of a pressure that is released upon the desired response, i.e., increased collection, and can therefore be considered a form of negative reinforcement. When using negative reinforcement in the training of horses, it is very important that the reinforcing stimulus is removed immediately when the desired goal is reached (Mills, 1998), and the riders in this study seem to have followed that advice. Because collection comprises a decrease in the horse’s stride
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length, a lower speed within the same gait can be assumed to represent a higher degree of collection, if performed by high-level dressage horses. Yet the riders’ lumbar backs became more extended with decreasing speed in collected trot (Fig. 1). This indicates that these high-level horses were able, and consequently allowed, to perform the slow collected trot without the support from frequent half-halts. This difference between a slow collected trot and passage is explainable from the fact that the passage represents a higher degree of collection compared to collected trot (FEI, 2011). However, the results do suggest that the riders needed to use more active leg aids at a slower collected trot: the rider’s knees were lowered and the range of longitudinal displacement of the rider’s toes tended to increase as speed decreased (Fig. 1 and Table 1). Both pitch rotation of the rider’s pelvis and the longitudinal displacement of the rider’s seat were significantly less phase-shifted in relation to the horse in passage compared to collected trot, and in collected trot the phase-shift for the longitudinal displacement of the rider’s neck decreased significantly with decreasing speed, i.e., increased collection. In free trot, on the other hand, the phase-shift between rider and horse increased for the vertical displacement of the rider’s seat and the longitudinal displacement of the rider’s neck (Table 2). It has previous been found that an expert rider’s movements are less phase-shifted in relation to the horse compared to a novice rider riding the same horse (Lagarde et al., 2005). It has also been shown that an expert rider has a more specific effect (i.e., uniform across horses) on the horse’s head movements compared to a novice (Schöllhorn, Peham, Licka, & Scheidl, 2006), and that the regularity of the horse’s movements increases when ridden by an expert rider, both compared to a novice rider (Lagarde et al., 2005) and compared to trot in hand (Peham, Licka, Schobesberger, & Meschan, 2004). Taken together, these results thus suggest that a more active and purposive influence from the rider correlates with a decrease in phase-shift between horse and rider. 5. Conclusion Even though the basic movement pattern of the rider has been shown to be closely related to the horse’s movements, the results of the current study suggest that differences in the rider’s body position and movement synchronicity relative to the horse observed between different degrees of collection at the trot are predominantly related to active rider intervention, at least among high-level dressage riders. The findings give a scientific insight into horse–rider interaction, providing some clues to how different gait patterns are induced and maintained by the rider. Conflict of interest None of the authors of this paper has a financial or personal relationship with other people or organisations that could inappropriately influence or bias the content of the paper. Acknowledgements This study was supported by grants from the Swedish Foundation for Equine Research, Sveland Insurance Company, Ulla Håkanson and the Stiftung Forschung für das Pferd, Zurich, Switzerland. The authors wish to thank Sören Johansson, Nina Waldern and Thomas Wiestner for excellent technical assistance and the all riders for their participation. References Byström, A., Rhodin, M., von Peinen, K., Weishaupt, M. A., & Roepstorff, L. (2009). Basic kinematics of the saddle and rider in high-level dressage horses trotting on a treadmill. Equine Veterinary Journal, 41, 280–284. Byström, A., Rhodin, M., von Peinen, K., Weishaupt, M. A., & Roepstorff, L. (2010). Kinematics of saddle and rider in high-level dressage horses performing collected walk on a treadmill. Equine Veterinary Journal, 42, 340–345. Clayton, H. M. (1994). Comparison of the stride kinematics of the collected, working, medium and extended trot in horses. Equine Veterinary Journal, 26, 230–234. Decarpentry (1971). Academic equitation: A preparation for international dressage tests. London: J.A. Allen. German National Equestrian Federation [FN]. (1997). The principles of riding (Completely rev. ed.). Buckingham: Kenilworth.
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