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2.1.2022 How good are we at seeing back movement in horses?

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Rater agreement for assessment of equine back mobility at walk and trot compared to quantitative gait analysis

Have you ever heard someone tell you that your horse needs to move more through his back, or that he looks stiff through his back? If you’re a rider, then I’m fairly sure the answer will be yes. But how much can we rely on this information? How good are we at recognising how well (or not) a horse is moving through his back?

A team of researchers asked 70 veterinarians, physiotherapists and veterinary students to watch 12 horses move (video footage), and to note down different aspects of the movement of the back. The researchers wanted to find out if the participants could repeatably describe the movement of the horse’s back, whether their findings would agree with each other, and whether their findings would agree with gait analysis findings (i.e. objective measurements taken using technology, as opposed to the human eye).

What the study found was that generally each person would come up with different findings each time, that the participants generally did not agree with each other in terms of what movement they were seeing, and that what the participants reported that they saw did not fit with what the technology measured.

This leads to the conclusion that we should be careful how much emphasis we put on watching the movement of the horse’s back (especially in lameness assessment), and to the recommendation that more objective measurement systems are developed to give us accurate information where it’s needed in the clinical setting.

You can read the full article here.



Lameness assessment in horses is still predominantly performed using subjective methods. Visual assessment is known to have moderate to good intra-rater agreement but relatively poor inter-rater agreement. Little is known about inter- and intra-rater agreement on the evaluation of back motion, for which no objective measurement technique in a clinical setting is available thus far.


To describe inter- and intra-rater agreement of visual evaluation of equine back mobility.

Study design

Rater reliability study using a fully crossed design in which all horses are rated by all observers. This data is compared with objective gait analysis.


Seventy equine professionals (veterinarians and physiotherapists) and veterinary students evaluated videos of 12 healthy horses at walk and trot on a hard, straight line. Nine parameters related to back mobility were scored: general mobility, thoracic, lumbar, lumbosacral flexion and extension and left and right thoracolumbar latero-flexion. All parameters were compared with simultaneously measured quantitative motion parameters. After 1 month, six randomly chosen horses were re-evaluated by 57 observers.


For each parameter inter- and intra-rater agreements were calculated using intra-class correlation coefficients. For all parameters, inter-rater agreement was very poor (<0.2). The mean intra-rater agreement of all observers and for all parameters was poor (approximately 0.4) but varied between 0.0 and 0.96 for individual observers. There was no correlation between the visual subjective scoring and objective gait analysis measurements.

Main limitations

Horses were scored from videos and by lack of any existing (semi-) quantitative system, a custom-made system had to be used.


The poor inter- and intra-rater agreements of visual scoring of mobility of the equine back and the disagreement between subjective and objective gait analysis data, demonstrate the need for the development and introduction of objective, quantitative and repeatable techniques to assess equine back motion.

Citation: Spoormakers TJP, Graat EAM, Serra Bragança FM, Weeren PRv, Brommer H (2021) Rater agreement for assessment of equine back mobility at walk and trot compared to quantitative gait analysis. PLoS ONE 16(6): e0252536.

You can read the full article here.

© Sue Palmer, The Horse Physio, 2021

Treating your horse with care, connection, curiosity and compassion

January 2, 2022
Sue Palmer