Visual lameness assessment in comparison to quantitative gait analysis data in horses

A.M. Hardeman, A. Egenvall, F.M. Serra Bragança, J.H. Swagemakers, M.H.W. Koene, L. Roepstorff, P.R. van Weeren, A. Byström

Equine Veterinary Journal 2022;00:1-10


Background: Quantitative gait analysis offers objective information to support clinical decision-making during lameness workups including advantages in terms of documentation, communication, education, and avoidance of expectation bias. Nevertheless, hardly any data exist comparing outcome of subjective scoring with the output of objective gait analysis systems.
Objectives: To investigate between-and within-veterinarian agreement on primary lame limb and lameness grade, and to determine relationships between subjective lameness grade and quantitative data, focusing on differences between (1) veterinarians (2) live vs video assessment, (3) baseline assessment vs assessment following diagnostic analgesia.
Study design: Clinical observational study
Methods: Kinematic data were compared to subjective lameness assessment by clinicians with ≥8 years of orthopaedic experience. Subjective assessments and kinematic data for baseline trot-ups and response to 48 diagnostic analgesia interventions in 23 cases were included. Between and within-veterinarian agreement was investigated using Cohen's Kappa (κ). Asymmetry parameters for kinematic data ('forelimb lame pattern', 'hindlimb lame pattern', 'overall symmetry', 'vector sum head', 'pelvic sum') were determined, and used as outcome variables in mixed models; explanatory variables were subjective lameness grade and its interaction with (1) veterinarian, (2) live or video evaluation and (3) baseline or diagnostic analgesia assessment.
Results: Agreement on lame limb between live and video assessment was 'good' between and within veterinarians (median κ = 0.64 and κ = 0.53). There was a positive correlation between subjective scoring and measured asymmetry. The relationship between lameness grade and objective asymmetry differed slightly between (1) veterinarians (for all combined parameters, p-values between P < .001 and 0.04), (2) between live and video assessments ('forelimb lame pattern', 'overall symmetry', both P ≤ .001), and (3) between baseline and diagnostic analgesia assessment (all combined parameters, between P < .001 and .007).
Main limitations: Limited number of veterinarians (n = 4) and cases (n = 23), only straight-line soft surface data, different number of subjective assessments live vs
from video.
Conclusions: Overall, between-and within-veterinarian agreement on lame limb was 'good', whereas agreement on lameness grade was 'acceptable' to 'poor'. Quantitative data and subjective assessments correlated well, with minor though significant differences in the number of millimetres, equivalent to one lameness grade between veterinarians, and between assessment conditions. Differences between baseline assessment vs assessment following diagnostic analgesia suggest that addition of objective data can be beneficial to reduce expectation bias. The small differences between live and video assessments support the use of high-quality videos for documentation, communication, and education, thus, complementing objective gait analysis data.

Range of motion and between-measurement variation of spinal kinematics in sound horses at trot on the straight line and on the lunge. 

A.M. Hardeman, A. Byström, L. Roepstorff, J.H. Swagemakers, P.R. van Weeren, F.M. Serra Bragança

PLoS ONE 2020 12(2): e0222822


Clinical assessment of spinal motion in horses is part of many routine clinical exams but remains highly subjective. A prerequisite for the quantification of spinal motion is the assessment of the expected normal range of motion and variability of back kinematics. The aim of this study was to objectively quantify spinal kinematics and between -measurement, -surface and -day variation in owner-sound horses. In an observational study, twelve owner-sound horses were trotted 12 times on four different paths (hard/soft straight line, soft lunge left and right). Measurements were divided over three days, with five repetitions on day one and two, and two repetitions on day three (recheck) which occurred 28-55 days later. Optical motion capture was used to collect kinematic data. Elements of the outcome were: 1) Ranges of Motion (ROM) with confidence intervals per path and surface, 2) a variability model to calculate between-measurement variation and test the effect of time, surface and path, 3) intraclass correlation coefficients (ICC) to determine repeatability. ROM was lowest on the hard straight line. Cervical lateral bending was doubled on the left compared to the right lunge. Mean variation for the flexion-extension and lateral bending of the whole back were 0.8 and 1 degrees. Pelvic motion showed a variation of 1.0 (pitch), 0.7 (yaw) and 1.3 (roll) degrees. For these five parameters, a tendency for more variation on the hard surface and reduced variation with increased repetitions was observed. More variation was seen on the recheck (p<0.001). ICC values for  pelvic  rotations were between 0.76 and 0.93, for the whole back flexion-extension and lateral bending between 0.51 and 0.91. Between-horse variation was substantially higher than within-horse variation. In conclusion, ROM and variation in spinal biomechanics are horse-specific and small, necessitating individual analysis and making subjective and objective clinical assessment of spinal kinematics challenging.

The Effect of Kinesiotape on Flexion-Extension of the Thoracolumbar Back in Horses at Trot

C. Ericson, P. Stenfeldt, A.M. Hardeman, I. Jacobsen

Animals 2020, 10 (2), 301. doi:10.3390/ani10020301


Kinesiotape theoretically stimulates mechanoreceptive and proprioceptive sensory pathways that in turn may modulate the neuromuscular activity and locomotor function, so alteration of activation, locomotion and/or range of motion (ROM) can be achieved. The aim of this study was to determine whether kinesiotape applied to the abdominal muscles would affect the ROM in flexion-extension (sagittal plane) in the thoracolumbar back of horses at trot. The study design was a paired experimental study, with convenient sample. Each horse was randomly placed in the control or the intervention group and then the order reversed. Eight horses trotted at their own preferred speed in hand on a straight line, 2 × 30 m. Optical motion capture was used to collect kinematic data. Paired t-tests, normality tests and 1-Sample Wilcoxon test were used to assess the effects of the kinesiotape. No statistical significance (p < 0.05) for changes in flexion-extension of the thoracolumbar back in trot was shown in this group of horses. Some changes were shown indicating individual movement strategies in response to stimuli from the kinesiotape. More research in this popular and clinically used method is needed to fully understand the reacting mechanisms in horses.

Variation in gait parameters used for objective lameness assessment in sound horses at the trot on the straight line and the lunge. 

A.M. Hardeman, F.M. Serra Bragança, J.H.Swagemakers, P.R. van Weeren, L. Roepstorff

Equine Veterinary Journal 51 (2019) 831-839


Background: Objective lameness assessment is gaining more importance in a clinical setting, necessitating availability of reference values.
Objectives: To investigate the between -path, -trial and -day variation, between and within horses, in the locomotion symmetry of horses in regular use that are perceived sound.
Study design: Observational study with replicated measurement sessions
Methods: Twelve owner-sound horses were trotted on the straight line and on the lunge. Kinematic data were collected from these horses using 3D optical motion capture. Examinations were repeated on 12 occasions over the study which lasted 42 days in total. For each horse, measurements were grouped as 5 replicates  on the first and second measurement days and two replicates on the third measurement day.  Between measurement days 2 and 3, every horse had a break from examination of at least 28 days. Previously described symmetry parameters were calculated: RUD and RDD (Range Up/Down Difference; difference in upward/downward movement between right and left halves of a stride; MinDiff and MaxDiff (difference between the two minima/maxima of the movement; HHDswing and HHDstance (Hip Hike Difference-swing/-stance; difference between the upward movement of the tuber coxae during swingphase/stancephase). Data are described by the between-measurement-variation for each parameter. A linear mixed model was used to test for the effect of time, surface and path. Intraclass correlation coefficients (ICC) were calculated to access repeatability.
Results: Mean between-measurement-variation was (MinDiff, MaxDiff, RUD, RDD): 13mm, 12mm, 20mm, 16mm (head); 4mm, 3mm, 6mm, 4mm (withers) and 5mm, 4mm, 6mm, 6mm (pelvis); (HHDswing, HHDstance): 7 and 7mm. 
More between-measurement-variation is seen on the first measurement day compared to the second and third measurement days. In general, less variation is seen with increasing number of repetitions.
Less between-measurement-variation is seen on hard surface compared to soft surface. More between-measurement-variation is seen on the circle compared to the straight line. Between-horse variation was clearly larger than within-horse variation. ICC values for the head, withers and pelvis symmetry parameters were 0.68 (head), 0.76 (withers), 0.85 (pelvis). 
Main limitations: Lunge measurements on a hard surface were not performed.
Conclusions: Between-measurement-variation may be substantial, especially in head motion. This should be considered when interpreting clinical data after repeated measurements, as in routine lameness assessments.

Reliable and clinically applicable gait event classification using upper body motion in walking and trotting horses

C. Roepstorff, M.T. Dittmann, S. Arpagaus, F.M. Serra Bragança, A.M. Hardeman, E. Persson-Sjödin, L. Roepstorff, A. Imogen Gmel, M.A. Weishaupt

Journal of Biomechanics 2021 (114) 110146


Objectively assessing horse movement symmetry as an adjunctive to the routine lameness evaluation is on the rise with several commercially available systems on the market. Prerequisites for quantifying such symmetries include knowledge of the gait and gait events, such as hoof to ground contact patterns over consecutive strides. Extracting this information in a robust and reliable way is essential to accurately calculate many kinematic variables commonly used in the field. In this study, optical motion capture was used to measure 222 horses of various breeds, performing a total of 82 664 steps in walk and trot under different conditions, including soft, hard and treadmill surfaces as well as moving on a straight line and in circles. Features were extracted from the pelvis and withers vertical movement and from pelvic rotations.The features were then used in a quadratic discriminant analysis to classify gait and to detect if the left/right hind limb was in contact with the ground on a step by step basis. The predictive model achieved 99.98% accuracy on the test data of 120 horses and 21 845 steps, all measured under clinical conditions. One of the benefits of the proposed method is that it does not require the use of limb kinematics making it especially suited for clinical applications where ease of use and minimal error intervention are a priority. Future research could investigate the extension of this functionality to classify other gaits and validating the use of the algorithm for inertial measurement units.

Vertical movement symmetry of the withers in horses with naturally occurring forelimb and hindlimb lameness at trot

E. Persson-Sjödin, E. Hernlund, T. Pfau, P. Haubro Andersen, K. Holm Forsström, A. Byström, F.M. Serra Bragança,  A.M. Hardeman, L. Greve, A. Egenvall, M. Rhodin



The most prominent compensatory asymmetry is the head nod down in horses with a primary hindlimb lameness. A possible clinical pitfall is mistaking this for primary ipsilateral forelimb lameness, which might delay correct diagnosis. The objective of this study was to describe compensatory lameness patterns and to examine whether the relationship between the direction of head and withers movement asymmetry parameters can be used to distinguish horses with primary forelimb lameness from horses with a compensatory head movement asymmetry due to primary hindlimb lameness. Medical records and objective movement symmetry data, collected with high-speed cameras as part
of routine lameness investigations at four different locations, were retrospectively analysed. Head, withers and pelvis motion asymmetries in 241 horses trotting in a straight line were compared before and after successful diagnostic analgesia was performed on one limb. Linear models and paired t-tests were used to analyse the data. In horses with forelimb lameness, 78-83% showed ipsilateral head-withers asymmetry. In horses
with hindlimb lameness, 90% showed diagonal pelvis-withers asymmetry. In 27-33% of the hindlimb lame horses, a large ipsilateral head movement asymmetry was seen, while 82-83% of these horses still showed diagonal pelvis-withers asymmetry and thus contralateral head-withers asymmetry. This study demonstrates that head and withers movement asymmetry parameters generally indicate
the same forelimb in horses with forelimb lameness and indicate opposite forelimbs in horses with hindlimb lameness. Quantification of withers asymmetry is therefore a useful supplement in clinical objective lameness assessment and could help locate the primary lameness in hindlimb lame horses with a compensatory ipsilateral head movement asymmetry.

Differences in equine spinal kinematics between straight line and circle in trot

A. Byström, A.M. Hardeman, F.M. Serra Bragança, L. Roepstorff, J.H. Swagemakers, P.R. van Weeren, A. Egenvall

Scientific Reports | 2021 Jun 18;11(1):12832. doi: 10.1038/s41598-021-92272-2


Work on curved tracks, e.g. on circles, is commonplace within all forms of horse training. Horse movements on a circle are naturally asymmetric, including the load distribution between inner and outer limbs. Within equestrian dressage the horse is expected to bend the back laterally to follow the circle, but this has never been studied scientifically. In the current study 12 horses were measured (optical motion capture, 100 Hz) trotting on the left and right circles and on straight line without rider (soft surface). Data from markers placed along the spine indicated increased lateral bending to the inside (e.g. left on the left circle) of the thoracolumbar back (left -3.75°; right 3.61° vs. straight) and the neck (left -5.23°; right 4.80°). Lateral bending ROM increased on the circle (0.87° and 0.62°). Individual variation in straight-circle differences were evident, but each horse was generally consistent over multiple trials. Differences in back movements between circle and straight were generally small and may or may not be visible, but accompanying changes in muscle activity and limb movements may add to the visual impression.

Movement asymmetries in horses presented for pre purchase or lameness examination

A.M. Hardeman, A. Egenvall, F.M. Serra Bragança, M.H.W. Koene, J.H. Swagemakers, L. Roepstorff, P.R. van Weeren, A. Byström

Equine Veterinary Journal (2021) 00: 1–13. doi: 10.1111/evj.13453.


Background: The increasing popularity of objective gait analysis makes application in prepurchase examinations (PPE) a logical next step. Therefore, there is a need to have more understanding of asymmetry during a PPE in horses described on clinical evaluation as subtly lame.

Objectives: The objective of this study is to objectively compare asymmetry in horses raising minor vet concerns in a PPE and in horses raising major vet concerns with that found in horses presented with subtle single- limb lameness, and to investigate the effect of age/discipline on the clinicians' interpretation of asymmetry on the classifi- cation of minor vet concerns in a PPE. 

Study Design: Clinical case- series. 
Methods: Horses presented for PPE (n = 98) or subjectively evaluated as single limb low- grade (1– 2/5) lame (n = 24, 13 forelimb lame, 11 hindlimb lame), from the patient population of a single clinic, were enrolled in the study provided that owners were willing to participate. Horses undergoing PPE were assigned a classification of having minor vet concerns (n = 84) or major vet concerns (n = 14) based on findings during the dynamic- orthopaedic part of the PPE. Lame horses were only included if pain- related lameness was confirmed by an objective improvement after diagnostic analgesia ex- ceeding daily variation determined for equine symmetry parameters using optical mo- tion capture. Clinical evaluation was performed by six different clinicians, each with ≥8 years of equine orthopaedic experience. Vertical movement symmetry was meas- ured using optical motion capture, simultaneously with the orthopaedic examination. Data were analysed using previously described parameters and mixed model analysis and least squares means were used to calculate differences between groups. 

Results: There was no effect of age or discipline on the levels of asymmetry within PPE horses raising minor vet concerns. MinDiff and RUD of the head discriminated between forelimb lame and PPE horses raising minor vet concerns; MinDiff, MaxDiff, RUD of the Pelvis, HHDswing and HHDstance did so for hindlimb lameness. Two lameness patterns differentiated both forelimb and hindlimb lame from PPE horses with minor vet con- cerns: RUD Poll + MinDiff Withers – RUD Pelvis and RUD Pelvis + RUD Poll − MinDiff Withers. Correcting for vertical range of motion enabled differentiation of PPE horses with minor vet concerns from PPE horses with major vet concerns. 
Main Limitations: Objective data only based on trot on soft surface, limited number of PPE horses with major vet concerns. 
Conclusions: Combinations of kinematic parameters discriminate between PPE horses with minor vet concerns and subtly lame horses, though overlap exists.

Interpretation of objective gait analyses, including a comparison to subjective evaluation of lameness in horses.

A.M. Hardeman, A. Byström, A. Egenvall, F.M. Serra Bragança, J.H. Swagemakers, L. Roepstorff, P.R. van Weeren



Despite routine application of quantitative gait analysis in the equine practice nowadays, there is no guideline on the clinical interpretation of the objective data. The objectives of this study were therefore to investigate agreement between objective and subjective evaluation on the primary lame limb and to provide clinicians with guidelines on how to interpret their clinical data, based on scientific literature. Twenty-three horses, presented to the clinic for lameness evaluation and subjectively assessed as 1,2 or 3/5 (AAEP scale) single limb lame by one of the four participating veterinarians, were trotted on the straight line and on the lunge. Kinematic data were collected using 3D optical motion capture. Horses were evaluated subjectively, both live and on video assessment. A thorough interpretation of the objective data was performed and outcome was compared to the subjective assessment. Good agreement was achieved between subjective assessment and evaluation of the objective data. A structured overview of argumentation was obtained, which may serve as a guideline for clinicians to interpret their objective data. Main limitations were the limited number of participating horses and the fact that data were only collected on soft surface.

A first exploration of perceived pros and cons of quantitative gait analysis in equine clinical practice

A.M. Hardeman, P.R. van Weeren, F.M. Serra Bragança, H. Warmerdam, H.G.J. Bok

Equine Veterinary Education (2021) 1-7. doi: 10.1111/eve.13505


Background: Quantitative gait analysis is rapidly gaining ground in equine practice, and pros and cons are regularly discussed within the scientific literature. However, no data exist on the appreciation of the technique by equine clinicians, their motivation to use it or not, and their perception of its value in daily practice. 
Objectives: To make a first inventory of opinions, expectances and experiences of equine veterinarians concerning the use of quantitative gait analysis in their daily general practice. 
Study design: Survey. 
Methods: A questionnaire was sent out to a group of equine orthopaedic clinicians working in an equine clinic or practice. Respondents were classified as users (having clinical experience with quantitative gait analysis) or not (nonusers). Data were analysed using descriptive statistics.

Results: Within the sample population, users were more positive about the usefulness of quantitative gait analysis than nonusers. Veterinarians who purchased a system were motivated by better objectivity, transparency, documentation and client service. Main reasons not to purchase a system were costs and complexity of data interpretation. A minority of both users and nonusers deemed quantitative gait analysis also suitable for equine professionals other than veterinarians. 
Main limitations: Users (n = 40) outnumbered nonusers (n = 32), sample size was limited (n = 72) and insufficient to allow for generalisation of results. 
Conclusions: Users of quantitative gait analysis were more positive about the technology than nonusers. More data are needed to allow for generalisation of the results. Regularly repeating this survey may help in monitoring, and eventually guiding the process of integration of gait analysis technology within equine clinical practice by providing valuable information for individual clinics, educational institutions and the industry producing this technology.