Relationship between the forces acting on the horse's back and the movements of rider and horse while walking on a treadmill

Reasons for performing the study: The exact relationship between the saddle pressure pattern during one stride cycle and the movements of horse and rider at the walk are poorly understood and have never been investigated in detail. Hypothesis: The movements of rider and horse account for the force distribution pattern under the saddle. Method: Vertical ground reaction forces (GRF), kinematics of horse and rider as well as saddle forces (FS) were measured synchronously in 7 high level dressage horses while being ridden on an instrumented treadmill at walk. Discrete values of the total saddle forces (FStot) were determined for each stride and related to kinematics and GRF. The pressure sensitive mat was divided into halves and sixths to assess the force distribution over the horses back in more detail. Differences were tested using a one sample t-test (p<0.05). Results: FStot of all the horses showed 3 peaks (P1-P3) and 3 minima (M1-M3) in each half-cycle, which were systematically related to the footfall sequence of the walk. Looking at the halves of the mat, force curves were 50% phase-shifted. The analysis of the FS of the 6 sections showed a clear association to the rider’s and horse’s movements. Conclusion: The saddle force distribution during an entire stride cycle has a distinct pattern although the force fluctuations of the FStot are small. The forces in the front thirds were clearly related to the movement of the front limbs, those in the mid part to the lateral flexion of the horse’s spine and the loading of the hind part was mainly influenced by the axial rotation and lateral bending of the back. Potential relevance: This data can be used as a reference for comparing different types of saddle fit. Grund der Studie: Der genaue Zusammenhang zwischen Satteldruck und Bewegungsmuster eines Schrittzyklus und der Bewegung von Pferd und Reiter im Schritt ist noch nicht untersucht. Hypothese: Durch die Bewegung von Pferd und Reiter entstehen die Sattelkräfte unter dem Sattel. Methode: Sowohl Bodenreaktionskräfte, Kinematik von Pferd und Reiter wie auch Sattelkraft wurden synchron von 7 gut ausgebildeten Dressurpferden, die im Schritt auf dem Laufband geritten wurden, gemessen. Die Gesamtsattelkraft jedes Schrittes wurde mit den Bodenreaktionskräften korreliert. Um die Sattelkräfte detaillierter anzuschauen wurde die Kraftverteilung der beiden Hälften sowie der Sechstel evaluiert. Die Unterschiede wurden mit einem t-test (p<0.05) untersucht. Resultate: Die Totalsattelkraft zeigte 3 Maxima (P1-P3) und 3 Minima (M1-M3) in jedem Halbzyklus, welche mit dem Schrittzyklus systematisch korreliert werden konnten. Die Sattelkraft der beiden Hälften war zeitlich um 50% verschoben. Die Analyse der sechstel zeigte einen klaren Zusammenhang zwischen der Bewegung des Pferdes und des Reiters. Folgerung: Die Verteilung der Sattelkraft während eines Schrittzyklus hat ein konstantes Muster, obwohl die Amplituden klein sind. Die Kraftschwankung in den beiden vorderen Sechstel konnten mit der Bewegung der Vorderbeine in Zusammenhang gebracht werden, die in den mittleren Sechstel mit der Lateroflexion der Wirbelsäule und die Belastung in den hinteren Sechstel war hauptsächlich beeinflusst von der axialen Rotation und der seitlichen Biegung des Rückens. Potentielle Relevanz: Dieser Datensatz kann als Referenz benutzt werden um die Passform von verschiedenen Sätteln zu evaluieren

Influence of velocity on horse and rider movement and resulting saddle forces at walk and trot

To investigate the effect of increasing velocity within one gait on horse and rider movement and to describe the resulting changes in saddle forces, seven ridden dressage horses were examined on an instrumented treadmill. The speed ranged between 1.3-1.8 m/s at walk and 2.6-3.6 m/s at trot. Kinematics of the horse and rider, vertical ground reaction forces and saddle forces were measured simultaneously. Velocity dependency of each variable was assessed for the whole group with linear regression. With increasing velocity, the saddle forces at walk were mainly influenced by the accentuated rocking type of movement and at trot by the higher vertical dynamic and a more rigid horseback which resulted in increased counteracting force between horse and rider. Even small increases of velocity changed the dynamics of the movement pattern of the horse and consequently the forces emerging beneath the saddle: a 10% increase within the indicated speed range resulted in +5% (walk) and +14% (trot) higher total saddle force peaks. Accurate comparison of saddle forces requires speed-matched trials; velocity is therefore a factor which also has to be considered under clinical conditions

Saddle pressure distributions of three saddles used for Icelandic horses and their effects on ground reaction forces, limb movements and rider positions at walk and tölt

Icelandic horse riding practices aim to place the rider further caudally on the horse’s back than in English riding, claiming that a weight shift toward the hindquarters improves the quality of the tölt (e.g. giving the shoulder more freedom to move). This study compared saddle pressure patterns and the effects on limb kinetics and kinematics of three saddles: an Icelandic saddle (SIcel, lowest point of seat in the hind part of the saddle), a treeless saddle cushion (SCush) and a dressage-style saddle (SDres). Twelve Icelandic horses were ridden with SIcel, SCush and SDres on an instrumented treadmill at walk and tölt. Saddle pressure, limb forces and kinematics were recorded simultaneously. With SCush, pressure was highest under the front part of the saddle, whereas the saddles with trees had more pressure under the hind area. The saddles had no influence on the motion patterns of the limbs. The slight weight shift to the rear with SCush and SIcel may be explained by the more caudal position of the rider relative to the horse’s back

High-speed cinematographic evaluation of claw-ground contact pattern of lactating cows

To evaluate the manner in which a cow's claws make contact with the ground at the walk, the gait, and in particular the claw-ground contact pattern, were studied in 12 healthy, lactating dairy cows, using high-speed cinematography (500frames/s) while the animals were walking on a treadmill. The results showed that the limbs were advanced around the contralateral limbs in a sigmoid curve. The feet contacted the ground with the foot axis and the tips of the claws rotated slightly outwards. In all cows the lateral claws contacted the ground before the medial claws in the hindlimbs, and in 10/12 cows in the forelimbs. The heel of the lateral claws was the region of initial contact with the ground in the hindlimbs of all cows and in the forelimbs in 9/12 cows. Lateral 'heel first' contact in the fore and hindlimbs appeared to be the normal gait pattern in these animals. Compared with a previous study of heifers, lactating cows had a larger step width in the hindlimbs and a smaller step width in the forelimbs. These ground contact patterns offer an explanation for the predisposition to claw disorders of the lateral claw of the hindlimb. The results of this study reinforce the suggestion that soft floor surfaces should be provided for cattle to prevent mechanical injury to the claws

Applied load on the horse’s back under racing conditions

With the intention of limiting the weight on horses’ backs and guaranteeing maximal freedom of movement, commonly used racing saddles are small and have minimal cushioning. Poor saddle cushioning may limit performance or even affect soundness of the back. The aim of this study was to measure the pressure under an average racing saddle ridden by a jockey at racing speed. Saddle pressure using a medium-sized racing saddle (length 37 cm, weight 450 g) was measured in five actively racing Thoroughbred horses. All horses were trained at the same facility and ridden by their usual professional jockey, weighing 60 kg. The horses were ridden on a race track at canter (mean velocity, V1 ± standard deviation, SD: 7.7 ± 0.4 m/s) and gallop (V2 ± SD: 14.0 ± 0.7 m/s). Maximal pressure was 134 kPa at V1 and 116 kPa at V2. Mean peak pressure was 73.6 kPa at V1 and 54.8 kPa at V2. The maximal total force did not differ between the two velocities and was approximately twice the jockey’s bodyweight. The centre of pressure lateral range of motion differed significantly, with excursions of 23 mm at V1 and 37 mm at V2; longitudinal excursion was 13 mm for V1 and 14 mm for V2. The highest pressure (>35 kPa) was always localised along the spinous processes over an average length of 12.5 cm. It was concluded that racing saddles exert high peak pressures over bony prominences known to be sensitive to pressure

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

REASONS FOR PERFORMING STUDY: Little is known in quantitative terms about the influence of different head-neck positions (HNPs) on the loading pattern of the locomotor apparatus. Therefore it is difficult to predict whether a specific riding technique is beneficial for the horse or if it may increase the risk for injury. OBJECTIVE: To improve the understanding of forelimb-hindlimb balance and its underlying temporal changes in relation to different head and neck positions. METHODS: Vertical ground reaction force and time parameters of each limb were measured in 7 high level dressage horses while being ridden at walk and trot on an instrumented treadmill in 6 predetermined HNPs: HNP1 - free, unrestrained with loose reins; HNP2 - neck raised, bridge of the nose in front of the vertical; HNP3 - neck raised, bridge of the nose behind the vertical; HNP4 - neck lowered and flexed, bridge of the nose considerably behind the vertical; HNP5 - neck extremely elevated and bridge of the nose considerably in front of the vertical; HNP6 - neck and head extended forward and downward. Positions were judged by a qualified dressage judge. HNPs were assessed by comparing the data to a velocity-matched reference HNP (HNP2). Differences were tested using paired t test or Wilcoxon signed rank test (P<0.05). RESULTS: At the walk, stride duration and overreach distance increased in HNP1, but decreased in HNP3 and HNP5. Stride impulse was shifted to the forehand in HNP1 and HNP6, but shifted to the hindquarters in HNP5. At the trot, stride duration increased in HNP4 and HNP5. Overreach distance was shorter in HNP4. Stride impulse shifted to the hindquarters in HNP5. In HNP1 peak forces decreased in the forelimbs; in HNP5 peak forces increased in fore- and hindlimbs. CONCLUSIONS: HNP5 had the biggest impact on limb timing and load distribution and behaved inversely to HNP1 and HNP6. Shortening of forelimb stance duration in HNP5 increased peak forces although the percentage of stride impulse carried by the forelimbs decreased. POTENTIAL RELEVANCE: An extremely high HNP affects functionality much more than an extremely low neck

Kinetics and kinematics of the passage

Reasons for performing study: The load acting on the limbs and the load distribution between fore- and hindlimbs while performing specific dressage exercises lack objective assessment. Hypothesis: The greater a horse's level of collection, the more load is shifted to the rear and that during the passage the vertical load on the limbs increases in relation to the accentuated vertical movement of the centre of mass. Methods: Back and limb kinematics, vertical ground reaction force and time parameters of each limb were measured in 6 Grand Prix dressage horses performing on an instrumented treadmill at the trot and the passage. Horses were ridden by their own professional rider. Results: At the passage, horses moved at a slower speed (-43.2%), with a lower stride frequency (-23.6%) and, therefore, higher stride impulses (+31.0%). Relative stance duration of fore- and hindlimbs and suspension duration remained unchanged. While at the trot the diagonal limbs impacted almost simultaneously, the hindlimbs always impacted first at the passage; the time dissociation between landing and lift-off remained unchanged. Because of the prolonged stride duration, stride impulse and consequently limb impulses were higher at the passage in the fore- as well as in the hindlimbs (+24.8% and +39.9%, respectively). Within the diagonal limb pair, load was shifted from the forehand to the hindquarters (percentage stride impulse carried by the forehand -4.8%). Despite the higher impulses, peak vertical forces in the fore- and hindlimbs remained unchanged because of the prolonged absolute stance durations in fore- and hindlimbs (+28.1% and +32.2%, respectively). Conclusions: Based on the intralimb timing, the passage closely resembles the trot. Compared to other head-neck positions, the higher degree of collection resulted in a pronounced shift in impulse towards the hindquarters. Despite the higher limb impulses, peak forces acting on the limbs were similar to those observed at the trot. Potential clinical relevance: An understanding of load distribution between fore- and hindlimbs in relation to different riding techniques is crucial to prevent wear-and-tear on the locomotor apparatus