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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.
Trabecular bone remodeling around smooth and porous implants in an equine patellar model. The objective of this investigation was to examine the stress-morphology relationships for trabecular bone around implants with different surface characteristics. Stainless steel spheres with either a polished surface or a sintered-bead porous coating were implanted unilaterally into equine patellae and maintained for a 6 month period. Stereological methods were used to quantify the trabecular bone morphology and finite element analyses were performed to predict the trabecular bone stresses. In general, the remodeling response around the smooth implants was greater than that around those porou...
Laterality in the gallop gait of horses. Bilateral asymmetry in gallop stride limb contact patterns of four Quarter Horse fillies was documented by high-speed cinematography. Horses were filmed with rider by two cameras simultaneously while galloping along a straightaway. Even though signaled for each gallop lead an equivalent number of times, horses frequently switched leads, selecting the left lead nearly twice as often as the right. Velocities and stride lengths were greater for the left lead than the right, but stride frequencies did not differ between leads. Velocity effects were partitioned out in limb contact data analysis to ...
Software for analysis of equine ground reaction force data. Software for analysis of force plate recordings of the horse at normal walk is described. The data of a number of stance phases are averaged to obtain a representative tracing of that horse. The amplitudes of a number of characteristic peaks in the force-time curves are used to compare left and right front limbs and left and right hind limbs. The averaged tracings are plotted, default on the line printer or, via separate program, on a high quality pen plotter. A version of the program applicable for analysis of human force plate recordings, is available.
Endurance exercise in the horse–a review. Part I. Over the last 10 years, there has been a great increase in information on the physiological effects of endurance exercise in horses reflecting the increase in popularity of endurance riding throughout the world. This review, which is in two parts, examines energy considerations, fluid and electrolyte balance, acid-base balance, hormonal and metabolic changes, muscle function, renal and hepatic function, haematological changes and clinical problems encountered in endurance rides. Additionally, relevant information from studies in man is included.
Change in triceps muscle intracompartmental pressure with repositioning and padding of the lowermost thoracic limb of the horse. Triceps intracompartmental pressure was measured in the lowermost limb of the recumbent horse during the initial period of recumbency during elective surgical procedures in 11 horses. Intramuscular pressure, using an IM catheter, was measured with the thoracic limbs in 4 different positions, including (I) table-contact limb unadvanced-unsupported free limb, (II) table-contact limb unadvanced-supported free limb, (III) table-contact limb advanced cranially, unsupported free limb, and (IV) table-contact limb advanced cranially, supported free limb. Pressure was measured in the 4 positions with a...
Fracture toughness design in horse hoof keratin. An engineering fracture mechanics approach was applied to the analysis of the fracture resistance of equine hoof-wall. The relationship between fracture toughness and the morphological organization of the keratin hoof tissue was investigated. Fracture toughness was evaluated using the J-integral analysis method which employs the compact tension test geometry. Tensile tests were also conducted to evaluate the effect of the morphological organization on the stress-strain behaviour. Hoof-wall has greatest fracture resistance for cracks running proximally, parallel to the tubular component of the ...
Relationships between stride length, stride frequency, velocity, and morphometrics of foals. Velocity-dependent changes in stride length and frequency were studied in 19 male foals, 6 to 8 months of age, and were related to body morphometrics. Eighteen distance and 8 angle measurements were digitized from 16-mm films of standing foals. The total mass and the percentage of total mass acting through the forelimbs were also recorded. Stride length and frequency data were extracted from 16-mm films of 239 strides of the walk, trot, and canter-gallop. Polynomial-regression analysis was used to determine the equation that best described the relationship between data of stride length or freq...
Equine energetics. II. Energy expenditure in horses during submaximal exercise. Energy expenditure was measured in four geldings (433 to 520 kg) during submaximal exercise on a racetrack using a mobile open-circuit indirect respiration calorimeter. A total of 304 5-min measurements of O2 consumed and CO2 produced were taken. Measurements were made with and without riders. The amount of energy expended by the horses was exponentially related to speed and was proportional to the body weight of the riderless horse or the combined weight of the horse plus rider and tack. Total energy expended by the four horses walking, trotting, cantering was best described by the equation: ...
Variations in cross-sectional area and composition of equine tendons with regard to their mechanical function. The cross-sectional area, collagen content, dry weight as a percentage of the wet weight and the tendon fibre percentage of the cross-sectional area of the equine hindlimb were determined in the superficial and deep digital flexor tendons and the suspensory ligament at 10, 12 and six sites between tarsus and insertion respectively. The values of each of the four parameters varied between different sites in the same tendon, between different tendons within a horse and between analogous tendons of different horses. Within a tendon the cross-sectional area was inversely proportional to the collag...
Ground reaction force patterns of Dutch Warmblood horses at normal walk. The ground reaction force patterns from 20 clinically sound Dutch Warmblood horses (Group A) were recorded at the normal walk. The data from four to 10 stance phases of each limb were computer averaged after normalisation to the animal's body mass and to the stance time. This analysis method allowed comparison of data from left and right fore- and hindlimbs within and between horses. The left-to-right symmetry in the reaction force peaks of contralateral limbs of one horse exceeded 90 per cent. The time in the stance phase at which the peaks occur were even more symmetrically distributed. A ch...
J.B. Wolffe memorial lecture. Is the lung built for exercise? In summary, we have shown that the design of the pulmonary system from the architectural capacities of the lung parenchyma and respiratory muscles to the remarkable, multi-level neural integration of breathing pattern and respiratory muscle recruitment is clearly intended for the exercising state. Furthermore, the system shows remarkable capability for true adaptation, both phylogenetically and even within only a few generations within a species, when preservation of the organism's ability to survive and function is at stake. At the same time there are limits to the system's homeostatic capabi...
Symmetry in running. Symmetry plays a key role in simplifying the control of legged robots and in giving them the ability to run and balance. The symmetries studied describe motion of the body and legs in terms of even and odd functions of time. A legged system running with these symmetries travels with a fixed forward speed and a stable upright posture. The symmetries used for controlling legged robots may help in elucidating the legged behavior of animals. Measurements of running in the cat and human show that the feet and body sometimes move as predicted by the even and odd symmetry functions.
Relationship between spinal biomechanics and pathological changes in the equine thoracolumbar spine. The relationship between spinal biomechanics and pathological changes occurring in functionally normal equine thoracolumbar spines was studied in 23 horses. Ventrolateral vertebral body osteophytes occurred in 36 per cent of the spines. The majority occurred between the 10th and 17th thoracic vertebrae with the largest being found between the 11th and 13th thoracic vertebrae, the region of the thoracic spine where the greatest amount of lateral bending and axial rotation occurs. Impingement of the dorsal spinous processes was detected in 86 per cent of the spines with most lesions occurring be...
Exercise and the height of horses. The heights of 89 horses were measured at the withers before and after half a furlong of trotting exercise. The mean (+/- sd) height increase after exercise was 1.75 +/- 0.86 cm and the horses returned to their resting height within seven minutes. There was no linear relationship between gain in height and pre-exercise height.
A technique to quantify skin displacement in the walking horse. A method is presented for quantitative determination of skin movement over the underlying skeletal structures during normal locomotion of the horse. The principle of the method is simultaneous visualization of the position of the skin and the underlying bony structures, by marking the bones with implanted light-emitting diodes (LEDs) and the skin with self adhesive spot labels. Recordings were made using photography.
Dynamic model of the equine hindlimb during the swing phase. A dynamic model is developed to describe the swing phase of the hindlimb of a normally walking horse. The limb was represented by four rigid segments constrained to move in a sagittal plane only. The mathematical equations of motion of this four-element pendulum were formulated using Lagrange's theorem. The morphometric parameters from the hindlimb segments of 3 horses were determined using high-speed film analysis. Five muscle groups were incorporated in the model. Muscle activity was derived from earlier EMG measurements. Optimization of muscle moments resulted in a simulated swing movement ...
Electromyographic, myomechanical, and intraluminal pressure changes associated with acute extraluminal obstruction of the jejunum in conscious ponies. Bipolar electrodes, strain gauge force transducers, intraluminal pressure recording catheters, and extraluminal intestinal obstructors were surgically implanted in 4 ponies to record myoelectrical and mechanical activity of the distal portion of the jejunum and ileum. After determining normal intestinal activity and pressures, the distal portion of the jejunum was obstructed with an extraluminal obstructor. Myoelectrical and mechanical activity recorded from jejunal segments proximal to the obstruction increased significantly (P less than 0.01), whereas activity distal to the obstruction remai...
Locomotion and gait analysis. Gait analysis can play an important role in exercise physiology, racetrack ergonomics, lameness prophylaxis, and assessment of performance potential in racehorses. This article concentrates on the methods used for gait analysis and considers some basic data on the different gaits of the horse.
Exercise physiology. An overview. Through the study of equine exercise physiology, one can learn more about what happens to the body of the performance horse during all forms of exercise. Better understanding of skeletal, joint, tendon, and ligament adaptations to loading and stress may allow adjustments to be made in training techniques to reduce the incidence of injury. The information obtained from exercise research may also facilitate the investigation of questions such as the following: What makes one horse perform better than another? How can one bring out the optimal performance in each horse? How can one tell when a ho...
Training programs. A training program is designed with the aim of developing the specific physiologic capabilities required to perform a certain type of exercise. Such capabilities involve the psychologic familiarity with, and acceptance of, the required tasks, the development of the neuromuscular coordination to perform these tasks optimally, and the utilization of energy by the working muscles. This article presents some basic principles for the design of training programs and offers ideas on how these principles may be applied to the conditioning of horses.
In vitro mechanical properties of equine tendons in relation to cross-sectional area and collagen content. The mechanical properties of the deep digital flexor tendon (DDFT), the superficial digital flexor tendon (SDFT) and the suspensory ligament (SL) of the hindlimb of the horse were studied in vitro. The tendons were observed at several morphologically distinct sites. The loaded tendon is homogeneously strained, in spite of large variations in cross-sectional area. Consequently the modulus of elasticity was inversely proportional to the corresponding cross-sectional area and ranged from 738 MPa (megaPascal, N mm-2) to 1398 MPa within the DDFT, from 1000 MPa to 1282 MPa within the SDFT and from 5...
In vivo bone strain in the equine tibia before and after transection of the peroneus tertius muscle. The present study was undertaken to determine the influence of the peroneus tertius muscle on the loading regime of the tibia in the horse. Strain gauge rosettes were bonded to the cranial and caudal cortices of the left and right tibiae in six Shetland ponies. In vivo bone strain recordings were made before and after unilateral transection of the peroneus tertius muscle. Relatively large individual variations in response to transection were observed in both the experimental and the contralateral control limbs. The principal strain values on the cranial and caudal cortices increased during the...
Changes in digital venous pressures of horses moving at the walk and trot. Blood pressures from the catheterized lateral digital vein of the fore-limbs of 6 clinically normal horses were measured at rest, at the walk, and at the trot. Digital venous pressures were compared with the phases of the stride and weight-bearing forces, using electrogoniometry and a force platform. Rapid increases in digital venous pressures to maximal values were observed immediately before maximal forces during the support period of the stride. At the trot, increases in peak vertical forces were paralleled by increases in peak digital venous pressures. Seemingly, the hydrodynamics of the d...
Impact and shear resistance of turf grass racing surfaces for Thoroughbreds. The 2 dominant processes involved in the horse hoof-to-racing surface interaction are the shock loading of the horse's leg upon impact with the racing surface and rotation of the horse's hoof into the racing surface. These processes were measured as impact resistance (ie, the peak deceleration of a moving body upon impact with the test surface) and as resistance to shear. The objective of the present study was to measure physically (under a variety of conditions) those soil and turf factors related to the 2 processes. It was concluded that thatch accumulation and mowing height of the turf did ...
Direct current stimulation of bone production in the pony: observations with a diaphyseal osteotomy model. Electrically induced osteogenesis exhibits a dose response curve and can induce bone formation in the absence of trauma and in nonunions. Electrically induced osteogenesis, using direct electric current (DC) in a third metacarpal diaphyseal osteotomy model, in conjunction with internal fixation and postoperative loading, was investigated. Twelve young adult ponies of mixed sex were divided into 2 treatment groups (A and B) of 3 stimulated and 3 controls each and evaluated, using a specifically designed procedure. Stimulated ponies in both groups were given 20 microA of DC via an implanted bone...
Force development during sustained locomotion: a determinant of gait, speed and metabolic power. This paper develops three simple ideas about force development during sustained locomotion which provide some insights into the mechanisms that determine why animals change gait, how fast they can run, and how much metabolic energy they consume. The first idea is that the alternate stretch-shorten pattern of activity of the muscles involved in locomotion allows muscle-tendon units to function as springs, affecting the amount of force a given cross-sectional area of muscle develops, and the metabolic requirements of the muscles for force development. Animals select speeds and stride frequencies...
The role of compliance in mammalian running gaits. The running gaits used by both bipedal and quadrupedal animals are reviewed and contrasted. At high speeds, bipeds use both ordinary running, in which the legs move opposite one another, and hopping. Quadrupeds generally use the trot or its variations at moderate speeds, and first the canter and then the gallop as speed increases. Running in both bipeds and quadrupeds generally involves at least one aerial phase per stride cycle, but certain perturbations to running including running in circles, running under enhanced gravity, running on compliant surfaces and running with increased knee flexi...
