Gallop velocity and limb contact variables of quarter horses

High-speed cinematography was used to examine the relationship between velocity and linear and temporal ground contact variables of the equine transverse gallop gait. The stride characteristics of four Quarter horse fillies were used as a model. Horses were approximately thirty months of age and had been raised and trained similarly. Horses were filmed by two cameras simultaneously (243 frames/second) while galloping under the standardized conditions of a specially constructed 1.5m-wide track. Horses were all ridden with the same saddle and bridle by one person. Kinematic variables determined for sixty-two strides included stride length, step lengths and stride frequency as well as contact and non-contact periods of single limbs and combinations of limbs. Galloping velocity (10.0 to 15.0 m/sec) was strongly influenced by stride frequency (2.16 to 3.04 sec⁻¹) and to a lesser extent by stride length (4.41 to 5.56 m). Stride length and stride frequency were independent. Variations in velocity were not associated with any detectable variations in absolute or relative distances between successive limb impacts. Increases in stride length at constant stride frequency were accomplished by increasing the distance between fore limb impacts and also the distance between fore leading limb impact and the subsequent hind trailing limb impact. Decreases in stride duration with increased galloping velocity occurred at the expense of hind trailing limb unipedal contact, fore leading limb unipedal contact and the airborne phase duration.     

Biokinematics under Competitive Racing Conditions in Young Standardbred Trotters: A Preliminary Report

With the aim of evaluating equine performance in competitive trotter horses under normal racing conditions data of stride length, stride frequency and mean horses speed were obtained from 50, 2-year-old Italian winner fillies during the racing and the sprint laps of competition. The enhancement of speed in the sprint lap was obtained by increasing both stride length and stride frequency. Stride frequency for the racing and the sprint laps were (mean ± SD) 133.63 ± 3.93 and 138.97 ± 6.62 strides per minute, respectively and Stride length for the racing and the sprint laps were 7.17 ± 0.17 and 7.30 ± 0.11 m, respectively; mean speed was 48.18 ± 1.09 km/hr. The usefulness of the kinematic assessments is discussed as is its potential reference for future indicators of performance.     

Phenotypic Correlations of Stride Traits and Body Measurements in Lipizzaner Stallions and Mares

Besides being well known for their use in classical dressage, Lipizzaner horses are today becoming more and more popular for use in driving sport, with Croatia as the largest breeder in the world. To estimate their phenotypic predisposition for driving sport, this research analyzes the correlation between body measurements and traits of length and speed of walk and hand-led trot in 18 stallions (LS) and 53 mares (LM) by using a digital camera. Statistical analysis of the data concerning phenotypic correlations among the indicated traits has revealed the potential of documenting a large number of structural exterior body characteristics and quantitative measurements in Lipizzaner horses, and technical equipment has been found to be useful in research of stride traits. Higher withers height (WH) achieved through breeding was found to be negatively correlated with the number of strides per second during walk and trot, but positively correlated with walk stride length, especially in LS. Higher values for chest girth (CG) and cannon bone circumference (CBC) were found to be positively correlated with speed, as well as with stride length in LS, and negatively correlated with the number of strides per second during walk and trot in both LS and LM. Because for many years the goal of breeding Lipizzaners in Croatia has been to obtain a bigger body format and longer stride, leading to better results in a driving sport, these findings confirm breeding goals in selection work guided toward better stride length and extended stride as the most desirable traits for driving sport.     

Linear and Temporal Kinematics of the Walk in Warmblood Foals

Kinematic variables of the walk in adult horses have been well described in the literature, but few studies have investigated growth-associated changes in these parameters. The objective of this study was to quantify linear and temporal walk patterns in Warmblood foals during the preweaning growth period. Nine foals were videotaped at the walk at 3, 11, and 21 weeks of age. Repeated-measures analyses were used to compare trait means between age groups. No significant effects owing to gender were found. Although stride length and stride duration increased as foals aged, neither differed across age groups when adjusted for wither height or velocity. Most kinematic variables did not differ across age groups when adjusted for Froude number. Overstride distance decreased by more than 40% in a linear manner from 3 to 21 weeks, and had an inverse relationship with distance between diagonal limbs during stance phase. Diagonal stance duration was greater than lateral stance duration for all age groups, indicating foals did not achieve an even, four-beat rhythm by the end of the study period. Changes in walk kinematics over time were independent of differences in velocity and increasing height during growth, and may indicate the need to account for body length or other morphometrics when assessing gait parameters in growing animals. Further research is needed during postweaning growth to determine when kinematic variables become consistent with those of adult horses.     

Neck and shoulder motion of the gallop stride

The motion patterns of the neck and shoulders during the gallop stride were documented using high-speed cinematography. The gallop stride characteristics of 4 Quarter Horse fillies, approximately 30 months of age, were used as a model. Horses were housed and fed together and received the same amount and type of limited training; and were all ridden with the same tack and by the same person. Both sides of each horse were filmed simultaneously (243 frames/sec) while galloping individually along a 1.5-m-wide track. Kinematic variables describing 29 strides (mean velocity 13.1 m/sec, stride frequency 2.6 strides/sec, stride length 5.1 m) included linear and temporal measurements of the maximum and minimum heights of the wing of the atlas, spine of the scapula, shoulder joint and elbow joint; maximum and minimum angles with respect to the horizon of the neck, shoulder and arm segments; and maximum and minimum relative angles between the neck and shoulder, and shoulder and arm segments. Differences (P<.05) between the leading and trailing sides of the body were identified for 12 of a total of 27 spatial measurements reported for the neck, shoulder and arm, including minimum height of the scapula spine, maximum height of the scapula spine and elbow joint, maximum absolute angle of the shoulder segment, and minimum angle between neck and shoulder segments. Of 18 temporal measurements reported involving the neck, shoulder and arm, 14 differed (P<.05) between leading and trailing sides. Kinematic events describing the motion of the leading and trailing shoulder and arm segments were ordered and tabulated in the temporal sequence of the normal gallop stride. Results indicated that the motion patterns of the shoulder and arm segments were highly specific to the leading and trailing sides of the body in the equine gallop stride. The work required for vertical displacement of the center of mass in galloping was estimated to be approximately 98,500 J/km or 23.5 kcal/km; equivalent to approximately 6 percent of the total energy expenditure for galloping 1 km.     

Angular joint parameters in the andalusian horse at walk, obtained by normal videography

Angular parameters from both front and hind limb joints of 17 Andalusian purebred stallions at walk (velocity, 1.68±0.14 m/s; stride length, 1.84±0.14 m; stride frequency, 0.91±0.07 strides/s and stride duration, 1.09±0.06 s) were recorded using normal computer-aided videography. Neither intraindividual (six strides) or interindividual variation coefficients (%) were higher than 10% for the basic maximum or minimum joint angle stride parameters. Only some parameters for the shoulder joint were high (arm=24.91%). These parameters may be useful for comparison with those from other horses under different conditions (health, training, age, etc.). The instant of maximal flexion during stride is also presented, with stride beginning in the mid-stance position of the right forelimb; variation coefficients were around 10–15% for all joints except the shoulder, which showed highly irregular patterns for both intraindividual (50.56%) and interindividual (33.10%) variation. In conclusion, normal computer-aided videography systems can be useful for the analysis of certain stride parameters in slower gaits, such as walking.     

Linear and temporal stride characteristics of 3-day event horses at a CCI*** 3-day event horse inspection

AIMS: To quantify the linear and temporal characteristics of the trot of 3-day event horses during the preliminary horse inspection of an advanced grade CCI*** 3-day event. METHODS: A cross sectional study was made of the kinematics of 24 3-day-event horses during the first horse inspection at a CCI*** level S-day event. Video footage was digitised and linear and temporal measurements were made. RESULTS: The horses trotted for an average of 10.44+/-1.55 strides. Spatial measurements were made on an average of 5.66+/-0.92 consecutive strides when the horses were within the calibration zone. The horses increased and then obtained a constant velocity within the calibration zone. Trotting on the asphalt track did not alter the relationships between stride length, stride duration and velocity when compared with previously published values. Horse-specific differences in stance and retraction percentages were identified. CONCLUSION: Horse specific differences were identified that may contribute to each horse's unique gait or kinematic fingerprint. It is proposed that the initiation of, and completion of, stance by the hind limb first may represent engagement of the hind quarters and be a response to dressage training.     

Gymnastic Training of Hippotherapy Horses Benefits Gait Quality When Ridden by Riders with Different Body Weights

The objective was to evaluate the effects of gymnastic training on stride characteristics of walk and trot in therapy horses carrying riders of different weights. Eighteen horses used for therapeutic riding 5 days/week were randomly divided into 2 groups. Nine horses performed gymnastic (GYM) exercises after therapeutic riding on 4 days/week for 3 months, 9 horses did no additional exercises (SED). On days 0 and 90, an inertial sensor mounted to the girth on the ventral midline was used to evaluate stride characteristics when horses were ridden at walk (1.3 m/second) and trot (3.0 m/second) by able-bodied riders representing rider: horse body weight ratios (BWRs) 15%, 20%, and 25%. On day 0, the measured variables did not differ significantly between sedentary (SED) and GYM groups, but on day 90, the following statistically significant results were found: GYM-trained horses had higher regularity for all BWRs at walk and 15% and 20% BWRs at trot. Higher stride symmetry was found in GYM-trained horses carrying 25% BWRs at walk and all rider weights at trot. Dorsoventral displacement was higher in GYM-trained horses when carrying 20% and 25% BWRs at walk and 25% BWRs at trot. Dorsoventral power was lower in SED-trained versus GYM-trained horses carrying 15% BWR at walk and 20% BWR at trot. A more regular and symmetrical stride with a larger range of dorsoventral trunk motion is likely to provide a better therapeutic riding experience.     

Canter lead change kinematics of superior olympic dressage horses

Limb contact variables of the gaits of superior dressage horses were determined for competitors at the 1988 Seoul Summer Olympic Games in the finals of the Individual Dressage competition. Two 16-mm motion picture cameras were aimed perpendicular to the plane of motion along the HXF and KXM diagonals of the standard dressage arena, and filmed at 100 fps. Nineteen of the horses selected as finalists for individual dressage medals were filmed during the Grand Prix Special test executing one-stride canter lead changes, two-stride canter lead changes and the left lead extended canter. Velocities, stride lengths and stride durations were 7.03±.07 m/s, 4.15±.05 m and .592±.004 s for the extended canter. Across all stride frequencies, score was optimized with extended canter strides of the greatest length, with no upper limit detected to optimal stride length. Canter strides with lead changes had lower velocities, shorter strides and longer durations than strides without a lead change, with velocities, stride lengths and stride durations, respectively, of 3.36±.05 m/s, 2.08±.04 m and .617±.003 s for one-stride canter lead change strides; 3.65±.07 m/s, 2.21±.04 m and .605±.003 s for pre-change canter two-stride lead change strides; and 3.95±.07 m/s, 2.44±.04 m and .621±.004 s for post-change canter two-stride lead change strides. This study provided the first objective documentation of the canter limb contact patterns of world-class dressage horses.     

Linear and temporal stride characteristics of 3-day event horses at a CCI*** 3-day event horse inspection

Aims. To quantify the linear and temporal characteristics of the trot of 3-day event horses during the preliminary horse inspection of an advanced grade CCI*** 3-day event.

Methods. A cross sectional study was made of the kinematics of 24 3-day-event horses during the first horse inspection at a CCI*** level 3-day event. Video footage was digitised and linear and temporal measurements were made.

Results. The horses trotted for an average of 10.44 ± 1.55 strides. Spatial measurements were made on an average of 5.66 ± 0.92 consecutive strides when the horses were within the calibration zone. The horses increased and then obtained a constant velocity within the calibration zone. Trotting on the asphalt track did not alter the relationships between stride length, stride duration and velocity when compared with previously published values. Horse-specific differences in stance and retraction percentages were identified.

Conclusion. Horse specific differences were identified that may contribute to each horse's unique gait or “kinematic fingerprint”. It is proposed that the initiation of, and completion of, stance by the hind limb first may represent “engagement of the hind quarters” and be a response to dressage training.     

Biokinematics Under Competitive Racing Conditions in Young Standardbred Trotter Horses: A Preliminary Report

The aim of this study was to evaluate equine performance in competitive trotter horses under normal racing conditions. Data of stride length, stride frequency, and mean horse speed were obtained from 50 2-year-old Italian fillies that were winners during the racing and the sprint laps of competition. The enhancement of speed in the sprint lap was obtained by increasing both stride length and stride frequency. Stride frequencies for the racing and the sprint laps were (mean ± SD) 133.63 ± 3.93 and 138.97 ± 6.62 strides per minute, respectively, and stride lengths for the racing and the sprint laps were 7.17 ± 0.17 and 7.30 ± 0.11 m, respectively; mean speed was 48.18 ± 1.09. The usefulness of the kinematic assessments as well as its potential reference for future indicators of performance is discussed in this study.     

Locomotor, cardiocirculatory and metabolic adaptations to training in Andalusian and Anglo-Arabian horses

The effects of two training programmes in 20 Andalusian and 12 Anglo-Arabian horses were evaluated by an increasing intensity work test at velocities of 4, 5, 6, 7 and 8 m sec(-1). Heart rate was monitored and blood samples were drawn at rest and after each velocity to analyse packed cell volume, haemoglobin concentration, plasma lactate and potassium levels. Furthermore, the programmes were video-taped and stride length, duration and frequency, stance (restraint and propulsion), swing phase durations and stride vertical component were measured. The training protocol of the Andalusian horses produced significant decreases in the cardiovascular, haematological and metabolic responses to exercise. Locomotory training adaptation consisted of an increased stride frequency and a reduced stride length and vertical stride component. The last variable was the limiting factor of stride length both before and after training in the Andalusian horses. A different training protocol for show-jumping competition in Anglo-Arabian horses failed to show significant differences in the studied parameters to the work test, although an increase in stride length at velocities of over 6 m sec(-1) was observed. Stride vertical component did not have an effect on the physiological response to exercise, either before or after training.     

Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. 5. Kinematic effects

AIM: To examine the effect of race training on kinematic parameters of the trot in a sample of 2-year-old Thoroughbred fillies. METHODS: Two-year-old Thoroughbred fillies that had been either trained for racing (n=7) or left untrained in small paddocks (n=7) were examined for lameness, and linear and temporal kinematic data were collected from video recordings of each horse trotted in-hand, 5, 9 and 13 weeks after the beginning of training. Horses were graded as: sound (Grade 0), suspected but not obviously lame (Grade 1), or definitely lame at the trot (Grade 2). RESULTS: Mean velocity at the trot did not vary with lameness grade. Compared with horses classified as sound (Grade 0), horses classified as suspected or definitely lame (Grades 1 and 2) had shorter (2.55 (SE 0.02) vs 2.41 (SE 0.02) and 2.44 (SE 0.03) m; p<0.001) and faster (671 (SE 3) vs 645 (SE 1) and 647 (SE 4) msec; p<0.001) strides. None of the linear or temporal parameters measured varied significantly between the successive observation periods. When data from sound horses were pooled, the training group trotted at a higher mean velocity (4.22 (SE 0.08) vs 3.22 (SE 0.06) m/sec; p<0.001) and with a longer stride length (2.79 (SE 0.05) vs 2.18 (SE 0.06) m; p<0.001) than the untrained group. The stride duration was longer (669 (SE 7) vs 662 (SE 9) msec; p=0.01), stance period was shorter (34.1 (SE 0.6) vs 39.3 (SE 0.7) %; p<0.001) and mid-stance was achieved earlier in the stride (12.1 (SE 0.6) vs 13.1 (SE 0.2) %; p=0.001) in the trained than the untrained group. A longer swing phase in the trained group was associated with an increase in retraction time (9.2 (SE 0.2) vs 7.6 (SE 0.3) %; p=0.001). CONCLUSIONS: These data indicate that early race training in young Thoroughbreds was associated with quantifiable changes in linear and temporal kinematic parameters of the trot, which were related to the race-training objective of improving the horse's ability to work at higher velocities. CLINICAL RELEVANCE: Race training resulted in changes in the gait of non-lame horses at the trot, which should be considered during veterinary lameness examinations.     

The interrelationships of stride lengths and stride times to velocities of galloping horses

Side view slow motion movies of galloping horses were taken and analyzed to determine horse velocity, limb velocity, stride length, stride time, and the swing and support timesof the stride. Multivariate statistical methods were used to evaluate the interrelationships of theseparameters. A linear relationship between horse velocity and limb velocity was observed; however, two groups could be distinguished within the trials. In one group, in which the horses were galloping normally, a one-to-one relationship of limb velocity to horse velocity was noted. In the other group, in which the majority of the horses were either lame or restrained by the rider, limb velocities were higher than horse velocities.In general, as horse velocity increased, stride length increased and stride time decreased due to decreases in both the swing and support times of the stride. Increases in stride length contributed more to increases in horse velocity than changes in either swing or support times. Changes in stride length had the greatest effect upon the velocities of those horses that were either lame or restrained by the rider, while the effects of changes in swing and support times contributed relatively more to changes in velocities of the horses which were galloping normally.This study suggests that in lame horses, limb velocity is proportionally greater than horse velocity due to decreases in stride length and stride time.     

The effect of training on stride parameters in a cohort of National Hunt racing Thoroughbreds: A preliminary study

Reasons for performing study: The influence of training on stride parameters is controversial and to date there is no information on how training influences stride parameters during high‐speed locomotion in the field. Objective: To determine the influence of training on stride variables during high‐speed locomotion in Thoroughbred racehorses. Methods: Speed, stride frequency, stance and protraction times were quantified in 8 Thoroughbreds with foot mounted accelerometers and GPS sensors during their first week of canter after the summer break and 6 months into training. Results: At a speed of 11 m/s, stride frequency was (mean ± s.d.) 2.160 ± 0.120 strides/s pre‐ and 2.167 ± 0.083 strides/s post training; mean stance time was 125.3 ± 9 ms pre‐ and 125.9 ± 7 ms post training; protraction time was 340.7 ± 20.4 ms pre‐ and 337.2 ± 14.3 ms post training. The increase in stride frequency and the decrease in protraction time after training were significant. There was no statistically significant difference in the maximum speed reached by each horse pre‐ and post training. Conclusions: Stance time stayed constant throughout the training season in the tested horses. A significant decrease in protraction time and a corresponding significant increase in stride frequency were observed after training. Potential relevance: Training of racehorses could be adapted to maximise the effect on modifiable parameters and reduce the risk of training‐induced pathologies. Further research will be conducted to investigate the effect of different training protocols on a large number of horses.     

The effect of collection and extension on tarsal flexion and fetlock extension at trot

A recent epidemiological study indicated that various factors may be related to injury in dressage horses, but the mechanism by which these injuries occur has yet to be determined. The suspensory ligament (SL) is a frequent site of injury, and it is assumed that greatest strain is placed on this structure in collected trot; this has yet to be proved conclusively. The study aimed to investigate the effect of collected and extended trot on the hindlimb movement pattern. Four dressage horses were fitted with markers and inertial motion sensors (IMS). High‐speed video was obtained for 2 strides on each rein in collected and extended trot on 3 different surfaces: waxed outdoor; sand/plastic granules; and waxed indoor. Maximal tarsal flexion during stance and distal metatarsal coronary band ratio (MTCR), representing fetlock extension, were determined. Inertial motion sensor data determined stride duration, speed and stride length. Data were compared between collection and extension within horses on each surface, and compared between surfaces. Collected trot had significantly lower speed and stride length but longer stride duration than extended trot on all surfaces. All horses had less tarsal flexion and fetlock extension in collected compared with extended trot (P<0.05), which is likely to increase SL loading. The study findings indicate that extended trot may increase SL strain, providing a possible explanation for the high incidence of SL injury in horses trained for extravagant movement. It is possible that substantial use of extended trot could be a risk factor for development of suspensory desmitis, which might be one contributory factor in the prevalence of suspensory desmitis in young horses repeatedly undertaking extravagant movement.     

The effects of treadmill inclination and speed on the activity of two hindlimb muscles in the trotting horse

Electromyographic activity (EMG) was used to determine how hindlimb muscle activation patterns vary with speed and incline in the horse. EMG was recorded using surface electrodes over the gluteus medius and tensor fasciae latae muscles during treadmill locomotion at trot for different combinations of speed (3.5 to 6 m/s) and inclination (0, 3 and 6%). Raw EMG signals were processed to determine stride duration, activity onset and end, and integrated EMG (IEMG). Stride and stance phase duration decreased linearly with increasing speed. Stride duration was not influenced by the slope. Onset and end of muscle activity came significantly earlier in the stride cycle when speed increased and later when inclination changed from 0 to 6%. The relative duration of the burst (percentage of stride duration) increased as running speed increased, but tended to decrease with increasing slope. The IEMG of the muscles increased with increasing speed and slope, the largest increase being observed in the tensorfasciae latae. It is concluded that both increases in speed and inclination lead to an increase in the integrated electromyographic activity and hence to a higher workload of the 2 hindlimb muscles investigated.     

The influence of lameness on equine stride length consistency

The aim of this study was to assess the influence of orthopaedic pain on the variation of stride length as a kinematic system-parameter in 21 horses with forelimb lameness. Data were collected while the horses were trotting on a treadmill during a minimum of 12 motion cycles, both before and after intra-articular or perineural anaesthesia. Stride length was assessed for each motion cycle, and the mean and standard deviation were calculated for each condition. Forelimb lameness was documented as percentage of asymmetry of vertical head movement. With significant decrease of forelimb lameness after regional anaesthesia, the SD of stride length increased significantly (+0.35%, P< 0.05). Our results show that in the presence of orthopaedic pain horses keep stride variability low, possibly because the lame horse employs an optimum compensatory mechanism to reduce the pain in the affected limb, and every deviation from this pattern increases pain.     

Locomotor Response to Exercise in Relation to Plasma Lactate Accumulation and Heart Rate in Andalusian and Anglo-Arabian Horses

To establish the effect of the locomotor pattern on heart rate (HR) and plasma lactate (LA), 28 horses, 18 Andalusian (AN) and 10 Anglo-Arabian (AA), aged 3–4 years, were studied. After a warm-up period, the horses performed a four-step test at 5, 6, 7 and 8 m/s, covering 1000 m at each velocity. HR was monitored, LA was analysed at rest and after each workload, and images were filmed. The locomotor parameters determined were stride duration (SD), frequency (SF) and length (SL), step and bipedal support durations, stance (restraint and propulsion) and swing phase durations, and stride vertical component. The HR and LA were significantly higher in the AN horses from velocities of 5 m/s. Similarly, the stride vertical component was higher in the AN horses at the trot and in the leading forelimbs at the gallop. Conversely, at all the galloping velocities, swing phase duration and stride length were longer in the AA horses. Significant correlations between HR, LA and locomotor pattern were only found in the AN horses. It was concluded that the greater stride vertical component in the AN horses limits SL and the cranial advancement of the hoof, with the result that reaching a longer SL triggers an increase in HR and LA. AA horses reach a balance between SL and SF, improving the efficiency of the gait.     

Multivariate statistical analysis of stride-timing measurements of nonfatigued racing Thoroughbreds

Standard univariate and bivariate statistical methods and two multivariate methods, stepwise regression and factor analyses, were used to analyze 17 stride-timing measurements of 22 racing Thoroughbreds filmed at the beginning of races. All horses were in a right-lead transverse gallop. Data were extracted from frame-by-frame analysis of 16-mm film taken with a high-speed camera. The mean stride duration was 0.405 s and the mean stride frequency was 2.47 strides/s. Stride duration had a higher correlation to the suspension-phase duration (r = 0.864) than to stride-stance-phase duration (r = 0.644). The 2 components of stride, the suspension and stride-stance phases, lasted on average, 0.114 s and 0.291 s or 28.07% and 72.01% of the stride duration, respectively. The correlation between stride-stance and suspension phases was low (r = 0.1767). Timing of the forelimbs, rather than overall stance-phase duration, may influence the duration of the suspension phase because four of seven variables selected in a stepwise-regression analysis were exclusively from the forelimbs. The stance-phase duration, and therefore swing-phase duration, of all four limbs differed significantly (P less than 0.05). The left forelimb (LF) and right hind limb (RH) had significantly shorter stance and single-support phases. Forelimb and hind limb pairs differed in their timing and coordination. There were differences in advanced placement and overlap of the hind limbs, compared with that in the forelimbs. Significant (P less than 0.05) differences were found between three limb overlap measurements. The overlap between the forelimbs was shortest and that between the hind limbs was the longest in duration.(ABSTRACT TRUNCATED AT 250 WORDS)