Abstract: Differences in movement asymmetry between surfaces and with increasing speed increase the complexity of incorporating gait analysis measurements from lunging into clinical decision making. This observational study sets out to quantify by means of quantitative gait analysis the influence of surface and speed on individual-rein movement asymmetry measurements and their averages across reins (average-rein measurements). Head, withers, and pelvic movement asymmetry was quantified in 27 horses, identified previously as presenting with considerable movement asymmetries on the straight, during trot in hand and on the lunge on two surfaces at two speeds. Mixed linear models (p < 0.05) with horse as the random factor and surface and speed category (and direction) as fixed factors analyzed the effects on 11 individual-rein and average-rein asymmetry measures. Limits of agreement quantified differences between individual-rein and average-rein measurements. A higher number of individual-rein asymmetry variables-particularly when the limb that contributed to movement asymmetry on the straight was on the inside of the circle-were affected by speed (nine variables, all p ≤ 0.047) and surface (three variables, all p ≤ 0.037) compared with average-rein asymmetry variables (two for speed, all p ≤ 0.003; two for surface, all p ≤ 0.046). Six variables were significantly different between straight-line and average-rein assessments (all p ≤ 0.031), and asymmetry values were smaller for average-rein assessments. Limits of agreement bias varied between +0.4 and +4.0 mm with standard deviations between 3.2 and 12.9 mm. Fewer average-rein variables were affected by speed highlighting the benefit of comparing left and right rein measurements. Only one asymmetry variable showed a surface difference for individual-rein and average-rein data, emphasizing the benefit of assessing surface differences on each rein individually. Variability in straight-line vs. average-rein measurements across horses and exercise conditions highlight the potential for average-rein measurements during the diagnostic process; further studies after diagnostic analgesia are needed.
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This research examines how speed and type of surface affect the movement asymmetry in horses, and how these factors increase the complexity of incorporating gait analysis measurements into clinical decision making.
Objective of the Research
This study aimed to quantify the impact of surface type and speed on the movement asymmetry of horses. This movement asymmetry was measured on individual reins and the averages across reins (average-rein measurements).
Methodology
The research was conducted on 27 horses known to present with notable movement asymmetries. During this study, the movement of their head, withers, and pelvic regions were analyzed as they trotted, both in hand and on the lunge, on two types of surfaces and at two different speeds.
A statistical approach known as mixed linear models was used to analyze and determine the effects of these factors on 11 types of individual-rein and average-rein asymmetry measures.
Difference between individual-rein and average-rein measurements were quantified using a statistical tool called limits of agreement.
Key Findings
The results of the study showed that individual-rein asymmetry variables were significantly affected by both speed (nine variables) and surface type (three variables) as compared to average-rein asymmetry variables (two for both speed and surface).
Six variables showed considerable differences between ‘straight-line’ and ‘average-rein’ assessments, with asymmetry values lesser in the case of average-rein assessments.
The limits of agreement bias varied between +0.4 mm and +4.0 mm, while the standard deviations fluctuated between 3.2mm to 12.9mm. This indicated varying levels of accuracy for the measurement techniques applied.
Implications of the Research
The study shows that fewer average-rein variables are influenced by speed, underscoring the advantage of comparing right and left rein measurements.
Only one asymmetry variable displayed a variable surface difference for individual and average-rein data. This demonstrates the advantage of assessing surface differences for each rein individually.
The discrepancies across straight-line and average-rein measurements in different horses and under varying conditions underscore the potential benefits of using average-rein measurements during the diagnostic process.
However, the researchers recommend further studies after diagnostic analgesia to better understand these findings.
Cite This Article
APA
Pfau T, Persson-Sjodin E, Gardner H, Orssten O, Hernlund E, Rhodin M.
(2021).
Effect of Speed and Surface Type on Individual Rein and Combined Left-Right Circle Movement Asymmetry in Horses on the Lunge.
Front Vet Sci, 8, 692031.
https://doi.org/10.3389/fvets.2021.692031
Department of Clinical Science and Services, The Royal Veterinary College, London, United Kingdom.
Persson-Sjodin, Emma
Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Gardner, Harriet
Department of Clinical Science and Services, The Royal Veterinary College, London, United Kingdom.
Orssten, Olivia
Department of Clinical Science and Services, The Royal Veterinary College, London, United Kingdom.
Hernlund, Elin
Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Rhodin, Marie
Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Conflict of Interest Statement
TP is the owner of EquiGait Ltd., a company providing gait analysis products and services. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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