Trunk kinematics and limb movement of horses walking backwards and forwards in hand and lifting a single limb

Equine physiotherapy commonly includes basic exercises such as walking backward (BW) and voluntary lifting of single limbs (SLL), but trunk movements during these have not been studied. In order to compare the trunk kinematics during BW and SLL with forward walking (FW), nine horses were measured in FW, BW and during SLL triggered by tactile cue. Kinematics were obtained from skin markers captured by ten high-speed video cameras. Trunk angles were calculated in sagittal and horizontal planes from withers, dorsal to spinous processes of the 16th thoracic vertebra (T16), 2nd and 4th sacral vertebrae (S2, S4), WT16S2 and T16S2S4 respectively. From the hooves, maximum hoof height during swing phase and horizontal distance between hoof and median body plane during swing and stance phases were determined. Dorsoventral range of motion (ROM) and maximum flexion of WT16S2 was significantly larger in BW than in FW, while laterolateral ROM was significantly smaller during hindlimb swing phase in BW and SLL than in FW. In contrast, dorsoventral ROM of T16S2S4 was significantly smaller during stance and swing phases of hindlimbs in BW compared to FW, and throughout the movement. During forelimb swing phase, T16S2S4 ROM was significantly larger in BW than SLL. Hindhoof height in SLL was significantly higher than in FW. Distance between median body plane and hooves was significantly larger in BW than in FW, and significantly larger in BW than in SLL for hindlimb swing phase. In BW, increased lumbosacral stabilisation and the larger area of support created by fore- and hindlimbs may represent a strategy to enhance body stabilisation, as BW entails some insecurity.

Effect of water depth on limb and back kinematics in horses walking on a water treadmill

Water treadmill (WT) exercise is frequently used for training/rehabilitation of horses. There is limited study into the effect of water depth on limb/back kinematics warranting investigation. The objective was to determine the effect of walking in different water depths, at the same speed, on limb/back kinematics measured simultaneously in a group of horses. Six horses (age:15±6.5 years) completed a standardised WT exercise session (19min duration; speed:1.6m/s; water depths:0.0/7.5/21.0/32.0/47.0cm). Ten waterproof light-emitting-diode tea-light-markers and reflective-spheres were affixed to the skin at predetermined locations; inertial-measurement-units were fixed to the poll/withers/left and right tubera coxae (TC)/sacrum to determine range-of-motion (ROM) changes of these locations. Univariable-mixed-effects-linear-regression-analyses were carried out, with a significance value of P≤0.05. At maximum carpal/tarsal flexion during swing, regression analyses showed a clear and consistent non-linear increase in carpal and tarsal flexion at increasing water depths (P<0.0001 for both variables). As water depth increased there was a significant increase in thoracic spine flexion-extension ROM (P<0.0001 at all thoracic sites) and increased dorsoventral and mediolateral ROM of the sacrum/left and right TC (P<0.001 for all variables) as water depth increased. Results suggest that horses responded to an increase in water depth until a threshold depth was reached when the biomechanical response levelled off, and there was increased pelvic roll. In conclusion, changes in limb kinematics brought about by relatively modest increases in water depth at walking speed of 1.6m/s are sufficient to induce significant changes in back/pelvic movement highlighting key issues with relevance for WT programme design.

Characteristics of the Flight Arc in Horses Jumping Three Different Types of Fences in Olympic Competition

Show jumping horses must execute fences of varying height and width, but the effect of this on jumping kinematics during the airborne phase have not been described. The aim of this study was to describe differences within- and between-horses in CM trajectory, trunk orientation and average trunk angular velocity in a group of elite horses executing three fences: vertical fence (1.60 m), spread fence (1.50 × 1.80 m), water jump (4.5 m) during an Olympic competition. Two-dimensional kinematic data (60 Hz) were collected from video cameras set perpendicular to each fence. After manual digitization, linear and angular variables related to the position and rotation of the CM and trunk were calculated. Linear fixed effects models evaluated within-group differences between fences and kinematic variables. Repeated measures correlation (rmcorr) evaluated within-horse associations between kinematic variables and fence type. Compared with the water jump, CM vertical velocity, CM peak height, and average trunk angular velocity were significantly higher (P < .05) and CM horizontal velocity was significantly lower (P < .05) for the vertical and spread fences. Peak CM height coincided approximately with the middle of the spread fence, toward the take-off for the water jump and landing for the vertical fence. The trunk was significantly more inclined at take-off for the vertical fence and significantly less inclined for the water jump at landing. Rmcorr analysis revealed that individual horses generally employ similar jumping techniques for each fence type. Findings provide original insight into the mechanical requirements for elite horses jumping different fence types.

Faults in international showjumping are not random

Performance analysis (PA) involves the systematic observation and analysis of factors identified to enhance performance to improve athlete decision-making in a specific sport. PA is commonplace in human sports, yet despite potential advantages, its application remains limited in equestrianism. This study aimed to evaluate if factors anecdotally associated with performance in elite showjumping influenced competitive success. 250 combinations attempting 3,052 jumping-efforts across 2nd round European Fédération Equestre Internationale Nations Cup 2017 competition were analysed. Types of fault (e.g. pole down, refusal, etc.) were recorded as well as characteristics of the jump (e.g. jump type, approach angle). Combinations jumped clear at the majority of attempts (93.6; n=2,857) with faults only occurring at 6.4% of jumps (n=195). The most common faults were knock-downs (5.5%), time penalties (0.8%), faults at water jumps (0.3%) and refusal (0.2%). Faults were distributed across all fence types, however, were more common at upright fences (49%) and within combination fences (41%). A linear relationship was found between jumping-effort number and number of fences knocked-down (r=0.7; P<0.001). There were 2.8 times more knock-downs for the second half of the course (efforts 9-15) compared with jumping-efforts 1-7 (P<0.05). Faults were 4 times more likely at jumping-efforts 3, 4, 5 and 8 in the first half of the course (P<0.03) which increased to being 9 times more likely in the 2nd half of the courses (jumping-efforts 9, 10, 11, 12, 13 and 14; P<0.006). A straight approach to a jumping-effort reduced the chance of faults by 48% (P<0.0001) compared to a non-straight approach. These preliminary results suggest faults are not randomly distributed in elite showjumping and that patterns exist within fault accumulation demonstrating that the application of PA techniques in equestrian sport could lead to a performance advantage.

Limb and thoracolumbosacral kinematics over an upright and parallel spread fence

Jumping mechanics have been investigated at take-off, flight and landing, mainly in reference to the limbs with limited evaluation of the thoracolumbosacral region. The objectives of this study were to investigate head, neck, thoracolumbosacral and limb angles in a group of experienced showjumping horses (competing at 1.20-1.60 m) over an upright and parallel spread fence. Ten horses in active showjumping training were recruited (mean 8 years old). High-speed videography (240 Hz) was used to determine thoracolumbosacral kinematic variables of the approach and take-off. No significant differences between the upright and parallel spread fences were observed for any of the variables measured. Individual horse review showed that neck-trunk, thoracolumbar, lumbosacral, coxofemoral angles, take-off distance and speed patterns at take-off were consistent among horses and also repeatable between fence types. Head-neck, stifle and tarsal angles had great variability among horses. The main limitation of this study was that only 2D motion analysis was carried out. In conclusion, analysis of individual horse patterns showed that head, neck, back and limb angles were repeatable over submaximal upright and spread fences in ten horses. Some angles were consistent among horses, but others had individual horse variation.

Reducing peak pressures under the saddle at thoracic vertebrae 10-13 is associated with alteration in jump kinematics

There is little information about horse-saddle interaction at take-off for a fence, although there is potential that this could have an influence on performance. It was hypothesised that (1) maximum peak pressure under the saddle would occur in the phase of maximum thoracolumbar flexion prior to hindlimb take-off; and (2) limb and trunk kinematics at take-off over the fence would be affected by reducing peak pressure at Thoracic vertebrae (T)10-13 at the point in the stride where peak pressures occur. The peak pressures under the usual saddle (Saddle S) and a saddle modified to reduce peak pressures at T10-13 (Saddle F) were measured during approach and take-off over a 1.30 m upright fence in 12 elite jumping horses. The timing of peak pressures was determined by comparison with simultaneous video data. Shoulder, carpal flexion angle and trunk angle to the horizontal at hindlimb take-off, take-off distance from the fence and fetlock height above the fence were determined using high speed motion analysis. Peak pressures under the saddle at T10-13 and kinematic data were compared between Saddles S and F. Maximum peak pressures occurred at forelimb vertical, during hindlimb protraction, consistent with thoracolumbar ventroflexion. Saddle F was associated with significantly lower peak pressures at T10-13, greater shoulder and carpal flexion, a steeper trunk angle, and higher fetlock height above the fence than Saddle S. Forelimb take-off distance from the fence was not different between saddles, but hindlimbs were significantly closer to the fence with Saddle F, indicating potential increase in ventroflexion through the thoracolumbosacral region. These findings suggest that reducing peak pressures under the saddle at T10-13 are associated with altered kinematics during the approach and take-off over a fence, which may have a positive effect on jumping performance.