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Topic:Biomechanics
Biomechanics in horses refers to the study of the mechanical principles that govern movement and physical function in equine species. This field encompasses the analysis of gait, locomotion, and the forces exerted by and upon the horse's musculoskeletal system. Biomechanical studies often involve the use of motion capture technology, force plates, and computer modeling to assess how horses move and how various factors, such as conformation, training, and health status, influence their performance and soundness. Research in equine biomechanics contributes to understanding injury prevention, rehabilitation, and performance optimization. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanics of movement, the impact of external and internal forces, and the applications of biomechanical analysis in equine care and management.
Treadmill study of the range of back movement at the walk in horses without back pain. To evaluate back movement during walking in horses. Methods: 22 adult horses with no history or signs of back pain. Methods: 3-dimensional movements of markers on the hooves, head, and back were measured with a motion analysis system while the horses were walking on a treadmill. The positions of markers on the hooves, head, and the skin above the spinous processes of T5, T10, T16, L3, and 2 sacral vertebrae were recorded. From a minimum of 6 walking motion cycles/horse, marker movement and the time of occurrence of minimum and maximum marker positions within the motion cycle were determined. A...
A biomechanical comparison of headless tapered variable pitch and AO cortical bone screws for fixation of a simulated lateral condylar fracture in equine third metacarpal bones. To compare drilling, tapping, and screw-insertion torque, force, and time for the 4.5-mm AO and 6.5-mm Acutrak Plus (AP) bone screws, and to compare the mechanical shear strength and stiffness of a simulated complete lateral condylar fracture of the equine third metacarpal bone (MC3) stabilized with either an AO or AP screw. Methods: In vitro biomechanical assessment of screw-insertion variables, and shear failure tests of a bone-screw-stabilized simulated lateral condylar fracture. Methods: Eight pairs of cadaveric equine MC3s Methods: Metacarpi were placed in a fixture and centered on a biax...
Training affects the collagen framework of subchondral bone in foals. Subchondral bone provides structural support to the overlying articular cartilage and plays an important role in osteochondral diseases. There is growing insight that the mechanical features of bone are related to the biochemistry of the collagen network. In this study the effect of exercise on water, calcium and the collagen network (total collagen, lysyl-hydroxylation, hydroxylysylpyridinoline, and lysylpyridinoline crosslinks) of subchondral bone at two differently loaded sites (site 1: intermittently loaded; site 2: constantly loaded) is investigated in foals. Exercise influenced calcium c...
The application of an indenter system to measure structural properties of articular cartilage in the horse. Suitability of the instrument and correlation with biochemical data. A recently developed indenter system that aims at determination of local structural properties of the cartilage surface was evaluated for suitability in the horse. To this aim, maximum indenter force was measured of the articular surface and related to biochemical characteristics of the cartilage at different sites of the distal metacarpal bone (MC). Significant topographical variation exists in structural properties of the articular surface of the MC. The dorsal margin showed a significantly lower maximum indenter force than more centrally located areas, indicating an increased compliance und...
Effects of ground surface deformability, trimming, and shoeing on quasistatic hoof loading patterns in horses. To determine whether solar load distribution pattern on a solid nondeformable ground surface is the product of contact erosion and is the mirror image of load distribution on a deformable surface in horses. Methods: 30 clinically normal horses. Methods: Solar load distribution was compared among 25 clinically normal horses during quasistatic loading on a solid nondeformable surface and on a highly deformable surface. Changes in solar load distribution patterns were evaluated in 5 previously pasture-maintained horses housed on a flat nondeformable surface. Changes in solar load distribution cre...
Evaluation of a tapered-sleeve transcortical pin to reduce stress at the bone-pin interface in metacarpal bones obtained from horses. To evaluate stiffness and bone-pin interface stress for a transcortical tapered-sleeve pin (TSP) that incorporates bilateral tapered sleeves over a transcortical pin. Methods: 14 third metacarpal bones (MCIII) collected from adult horses of various breeds. Methods: Each MCIII was cut in half to provide 2 test specimens. Pins (conventional and TSP) of 3 diameters (6.35, 7.94, and 9.50 mm) were inserted in specimens (3 specimens for each diameter and each type of pin). The test fixture simulated a typical sidebar-span skeletal fixation device for horses. Single cycle load-deflection tests were p...
Effect of walking velocity on ground reaction force variables in the hind limb of clinically normal horses. To measure the effect of subject velocity on hind limb ground reaction force variables at the walk and to use the data to predict the force variables at different walking velocities in horses. Methods: 5 clinically normal horses. Methods: Kinematic and force data were collected simultaneously. Each horse was led over a force plate at a range of walking velocities. Stance duration and force data were recorded for the right hind limb. To avoid the effect of horse size on the outcome variables, the 8 force variables were standardized to body mass and height at the shoulders. Velocity was standard...
Comparison of bending modulus and yield strength between outer stratum medium and stratum medium zona alba in equine hooves. To determine whether the bending modulus and yield strength of the outer stratum medium (SM) differed from those of the SM zona alba (SMZA) and to what degree they differed. In addition, a comparison was made among our values and values reported elsewhere. Methods: 10 normal equine feet. Methods: A 3-point bending technique was used to determine the bending modulus and yield strength of the outer SM and SMZA. Efforts were made to minimize biological and technical factors that could influence the bending modulus. Results: Bending modulus of the outer SM was (mean +/- SD) 187.6 +/- 41.3 MPa, whe...
Basic three-dimensional kinematics of the vertebral column of horses trotting on a treadmill. To determine movements of the vertebral column of horses during normal locomotion. Methods: 5 young Dutch Warmblood horses that did not have signs of back problems or lameness. Methods: Kinematics of 8 vertebrae (T6, T10, T13, T17, L1, L3, L5, and S3) and both tuber coxae were determined, using bone-fixated markers. Measurements were recorded when the horses were trotting on a treadmill at a constant speed of 4.0 m/s. Results: Flexion-extension and axial rotation were characterized by a double sinusoidal pattern of motion during 1 stride cycle, whereas lateral bending was characterized by 1 pe...
Evaluation of dual energy x-ray absorptiometry for in situ measurement of bone mineral density of equine metacarpi. To determine the accuracy and precision of dual energy x-ray absorptiometry (DEXA) for measuring bone mineral density in horses in situ. Sample Population-12 randomly selected forelimbs from 12 horses. Methods: Metacarpi were scanned in 2 planes and DEXA measurements obtained for 6 regions of interest (ROI). Each ROI was isolated and bone density measured by Archimedes' principle. Linear regression analysis was used to determine the correlation between the 2 measurements at each ROI. An additional metacarpus was measured 10 times to determine the coefficient of variation for both techniques. R...
An in vitro biomechanical comparison of two interlocking-nail systems for fixation of ostectomized equine third metacarpal bones. To compare the mechanical properties of 2 interlocking-nail systems for fixation of ostectomized equine third metacarpi (MC3): (1) a standard interlocking nail with 2 parallel screws proximal and distal to a 1-cm ostectomy; and (2) a modified interlocking nail with 2 screws proximal and distal to a 1-cm ostectomy with the screws offset by 30 degrees. Methods: Twelve pairs of adult equine forelimbs intact from the midradius distally. Methods: Twelve pairs of equine MC3 were divided into 2 test groups (6 pairs each): torsion and caudocranial 4-point bending. Standard interlocking nails (6-hole, ...
Arthroscopic mosaic arthroplasty in the equine third carpal bone. To investigate survival and function of autogenous heterotopic osteochondral grafts in a site where injuries are common. Methods: Three osteochondral grafts were harvested arthroscopically from the femoropatellar joint and transplanted to the third carpal bone (C(3)). Nine months later, histologic, histomorphometric, and biochemical comparisons were made between the transplanted grafts in C(3) and tissue adjacent to the recipient site, the opposing radial carpal bone (C(r)), the donor site in the femoropatellar joint, and the sham-operated contralateral C(3). Methods: One mixed-breed pony and ...
Arthrodesis of the equine proximal interphalangeal joint: a biomechanical comparison of three 4.5-mm and two 5.5-mm cortical screws. To compare the biomechanical characteristics and mode of failure of 2 parallel-screw techniques for proximal interphalangeal joint arthrodesis in horses. Methods: Randomized block design, blocking for horse (1-5), method of screw fixation (three 4.5-mm vs two 5.5-mm), side (left limb vs right limb), and end (front limb vs hind limb). Constructs were loaded to failure in 3-point bending in a dorsal-to-palmar (plantar) direction. Methods: Twenty limbs (10 limb pairs) from 5 equine cadavers. Methods: A combined aiming device was used to facilitate consistent screw placement. Three parallel 4.5-mm...
Photoelastic stress analysis of strain patterns in equine hooves after four-point trimming. To evaluate changes in strain patterns in normal equine hooves following 4-point trimming, using photoelastic stress analysis. Methods: 15 equine front limbs with normal hoof configuration. Methods: Limbs were disarticulated at the carpometacarpal joint. Weight-bearing surfaces of each hoof were trimmed level to ensure 100% ground contact. Hoof walls were coated with a custom-made strain-sensitive plastic, and limbs were loaded to a third of body weight. Using a polariscope, strain distribution, magnitudes, and directions were evaluated in level hooves as well as before and after standardized ...
The anisotropic Young’s modulus of equine secondary osteones and interstitial bone determined by nanoindentation. The equine radius is a useful subject for examining the adaptation of bone histology to loading because in life the anterior cortex is loaded almost entirely in tension, the posterior cortex in compression. The histology of the two cortices is correspondingly different, the osteones and the interstitial lamellae in the posterior cortex having a more transversely oriented fibre arrangement than those in the anterior cortex. Presumably as a result of this histological difference, the posterior cortex is stronger in compression than the anterior cortex; the anterior cortex is stronger in tension ...
Effect of contact stress in bones of the distal interphalangeal joint on microscopic changes in articular cartilage and ligaments. To examine articular cartilage of the distal interphalangeal (DIP) joint and distal sesamoidean impar ligament (DSIL) as well as the deep digital flexor tendon (DDFT) for adaptive responses to contact stress. Methods: Specimens from 21 horses. Methods: Pressure-sensitive film was inserted between articular surfaces of the DIP joint. The digit was subjected to a load. Finite element models (FEM) were developed from the data. The navicular bone, distal phalanx, and distal attachments of the DSIL and DDFT were examined histologically. Results: Analysis of pressure-sensitive film revealed signific...
Methodology and validity of assessing kinematics of the thoracolumbar vertebral column in horses on the basis of skin-fixated markers. To determine the validity of using skin-fixated markers to assess kinematics of the thoracolumbar vertebral column in horses. Methods: 5 Dutch Warmblood horses without abnormalities of the vertebral column. Methods: Kinematics of T6, T10, T13, T17, L1, L3, L5, S3, and both tuber coxae were determined by use of bone-fixated and skin-fixated markers. Three-dimensional coordinate data were collected while horses were walking and trotting on a treadmill. Angular motion patterns were calculated and compared on the basis of 2-dimensional analysis of data from skin-fixated markers and 3-dimensional a...
Morphology of the laminar junction in relation to the shape of the hoof capsule and distal phalanx in adult horses (Equus caballus). The purpose was to investigate whether differences in equine hoof shape, which are inferred to alter foot function, are accompanied by differences in morphology of the laminar junction. Ten fore feet from adult horses were segregated into normal and low-angle groups, depending on the dorsal angle of the hoof wall. Twenty measurements of external hoof shape and four of the enclosed distal phalanx were tested for differences between groups, and for intragroup correlations. Three measurements of laminar morphology (spacing, orientation and degree of bend) were recorded for samples of up to 50 pri...
The force and contact stress on the navicular bone during trot locomotion in sound horses and horses with navicular disease. Mechanical overload due to poor conformation or shoeing has been suggested to contribute to the development of navicular disease. While studies have determined the compressive force exerted on the navicular bone in normal horses, this has not been reported for horses with navicular disease. Also, the force has not been converted to stress by correction for contact area. In this study we developed a technique for the determination of the contact area between the deep digital flexor tendon and the navicular bone in vivo, and used a forceplate system to determine the force and stress on the bone ...
Intra-articular pressure profiles of the cadaveric equine fetlock joint in motion. The study of the influence of motion and initial intra-articular pressure (IAP) on intra-articular pressure profiles in equine cadaver metatarsophalangeal (MTP) joints was undertaken as a prelude to in vivo studies. Eleven equine cadaver MTP joints were submitted to 2 motion frequencies of 5 and 10 cycles/min of flexion and extension, simulating the condition of lower and higher (double) rates of passive motion. These frequencies were applied and pressure profiles generated with initial normal intra-articular pressure (-5 mmHg) and subsequently 30 mmHg intra-articular pressure obtained by inje...
Effect of load on preferred speed and cost of transport. Horses have a tendency to utilize a relatively narrow set of speeds near the middle of a much broader range they are capable of using within a particular gait, i.e., a preferred speed. Possible explanations for this behavior include minimizing musculoskeletal stresses and maximizing metabolic economy. If metabolic economy (cost of transport, CT) and preferred speeds are linked, then shifts in CT should produce shifts in preferred speed. To test this hypothesis, preferred speed was measured in trotting horses (n = 7) unloaded on the level and loaded with 19% of their body weight on the level. T...
An in vitro biomechanical comparison of interlocking nail constructs and double plating for fixation of diaphyseal femur fractures in immature horses. To compare the biomechanical properties of intact immature horse femurs and 3 stabilization methods in ostectomized femurs. Methods: Eighteen pairs of femurs from immature horses aged 1 to 15 months, and weighing 68 to 236 kg. Methods: Thirty-four immature horse femurs were randomly assigned to 1 of 5 test groups: 1) interlocking intramedullary nail (IIN) (n = 6); 2) IIN with a cranial dynamic compression plate (I/DCP) (n = 6); 3) 2 dynamic compression plates (2DCP) (n = 8); 4) intact femurs tested to failure in lateromedial (LM) bending (n = 6); and 5) intact femurs tested to failure in caudo...
The hindlimb in walking horses: 1. Kinematics and ground reaction forces. The objective was to study associations between kinematics and ground reaction forces in the hindlimb of walking horses. Video (60 Hz) and force (2000 Hz) data were gathered for 8 strides from each of 5 sound horses during the walk. Sagittal plane kinematics were measured concurrently with the vertical and longitudinal ground reaction forces. The hindlimb showed rapid loading and braking in the initial 10% stride. The stifle, tarsal and coffin joints flexed and the fetlock joint extended during this period of rapid loading. The vertical ground reaction force showed 2 peaks separated by a dip; ...
The hindlimb in walking horses: 2. Net joint moments and joint powers. The objective of the study was to describe net joint moments and joint powers in the equine hindlimb during walking. The subjects were 5 sound horses. Kinematic and force data were collected synchronously and combined with morphometric information to determine net joint moments at each hindlimb joint throughout stance and swing. The results showed that the net joint moment was on the caudal/plantar side of all hindlimb joints at the start of stance when the limb was being actively retracted. It moved to the cranial/dorsal side around 24% stride at the hip and stifle and in terminal stance at t...
Evaluation of an in-shoe pressure measurement system in horses. To develop an objective, accurate method for quantifying forelimb ground reaction forces in horses by adapting a human in-shoe pressure measurement system and determine the reliability of the system for shod and unshod horses. Methods: 6 adult Thoroughbreds. Methods: Horses were instrumented with a human in-shoe pressure measurement system and evaluated at a trot (3 m/s) on a motorized treadmill. Maximum force, stance time, and peak contact area were evaluated for shod and unshod horses. Three trials were performed for shod and unshod horses, and differences in the measured values were examine...
Locomotor characteristics of horses with navicular disease. To determine whether force-plate evaluation of horses with navicular disease would reveal an abnormal gait that persists despite loss of sensation to the palmar foot region, which may predispose such horses to navicular disease. Methods: 17 clinically normal Thoroughbreds and 8 Thoroughbreds with navicular disease. Methods: Data on ground reaction forces were obtained in trotting horses, using a force plate. Force-time curve variables for clinically normal horses were derived from 4 points at the beginning and 4 points at the end of the vertical and craniocaudal horizontal plots. Principal com...
Reliability of two 2,400-m time-trial protocols for assessing performance of Standardbred racehorses. To evaluate the reliability of 2 time-trial protocols, 1 that involved use of a pacemaker and 1 that did not, for assessing performance of Standardbred racehorses. Methods: 3- to 7-year-old Standardbred maiden pacers. Methods: 11 Standardbred pacers were used to determine the reliability of a time-trial protocol that involved use of a galloping pacemaker. All tests were performed by a single driver. Horses were paced for an initial 1,600 m then raced and timed for the final 800 m. They were retested 9 days later. Twenty-two horses were used to determine the reliability of a time-trial protocol...
Screw fixation in lag fashion of equine cadaveric metacarpal and metatarsal condylar bone specimens: a biomechanical comparison of shaft and cortex screws. To compare acute fixation stability and insertion effort of cortex bone screws with and without a shaft inserted in lag fashion in equine metacarpal (metatarsal, MC(T)III) bone. Methods: Screw types with independent variables of screw diameter (4.5 or 5.5 mm) and shaft type (without shaft, with 20-mm shaft, or with 25-mm shaft) were studied. Bone specimens cut from distal equine MC(T)III condyles were used. After screw insertion in lag fashion into 2 bone blocks with an instrumented device, shear tests were conducted in a mechanical testing machine. Outcome variables of peak insertion torque, ...
