Pre and post images - useful or misleading? Don’t be fooled by the trickery….!

Dr. Russell MacKechnie-Guire

September 2020

In image A, the saddle is slipped to the right (orange arrow) and the rider is shortening through their left side with their seat displaced to the right. In image B, the saddle is straighter and the rider has an improved position as a result of the “intervention” – or is this a trick….? With reference to images C and D (same as the previous images, but now the limbs are visible) it can be seen that the horse is on different canter leads (image A and C = left lead and image B and D = right lead) - look at the orientation of the hoof. 

In the above scenario, riders may see these two images (A and B ) and believe the “intervention” has resolved the saddle slip and that their position is improved. The differences here, are as a function of the horse being on the opposite rein and the directional effects on locomotion and biomechanics. In addition, saddle slip generally only occurs on one rein. 

Riders could be under the impression that the “intervention” has 1) resolved the saddle slip; 2) that they are responsible for the saddle slip and 3) that the intervention has worked. Of course, if the intervention has worked and has been verified (correctly with no bias) then this is a positive.

The greater concern is if riders believe an intervention has worked, and it hasn’t. In these cases, the rider is likely not to address the underlying mechanics as to why the saddle is slipping. Evidence from (Greve and Dyson), and our own (MacKechnie-Guire et al.) has shown that the horse is the contributory factor for inducing saddle slip with the rider following the movements of the saddle and horse. It is appreciated that there are a small number of riders who may induce saddle slip however, in the majority of cases it is initiated by the horse due to multiple reasons - lameness, functional asymmetry, laterality, seasonal effect, travelling etc. research is ongoing to understand further. 

The purpose of this blog is to raise awareness, I recently received a pre and post image from a rider. This rider was not advised nor did she think to explore the underlying mechanics as to why the saddle had initially slipped as the intervention had “fixed” the problem. A few months later, the rider was still crooked and the saddle slip was more evident– what long term effect did this have on the horse+rider….? 

Saddle slip is something that requires a detailed understanding of both equine biomechanics and the interaction between the horse, saddle and rider. Correcting saddle slip is something that requires a team approach (all or some) veterinarian, saddle fitter, farrier, coach, therapist, biomechanist, horse+rider physio etc. along with regular monitoring and saddle fitting checks. Importantly, saddle slip can be an early indicator of movement asymmetry hence it is essential that it is addressed in order to limit further asymmetries developing.

  • Things to look for when viewing pre and post images.
    Foot fall – you will see with image C and D the grounded limb (green arrow) and flexed hindlimb (red arrow) has been indicated – it can be seen that the grounded/flexed limb (s) differ when on either the left / right rein. This is easily identified when looking at the orientation of the hoof
  • Pelvic roll / height – look at the top of the horse’s pelvis and observe if it rolls (falls away) in the same direction
  • Gait – walk, trot and canter have different mechanics hence will have a different effect on the horse+rider+saddle

I hope the above post helps. I am a massive advocate of using technology to help support horse + rider performance but the interpretation of information / findings is crucial and if performed incorrectly can be misleading and in the scenario presented here, could have a detrimental effect on the horse+rider. 

For meaningful comparisons to be made, the horse+rider need to be on the same rein, same moment in the stride cycle and same gait.

Please share to raise awareness.





Dr Russell MacKechnie-Guire

Friday 24 July 2020


An evidence based discussion about saddle slip - recently, there has been a lot of activity on social media about saddle slip. We and others have studied this area extensively, therefore the purpose of this post is to provide an evidence based discussion around the topic.

Saddle slip, defined as a saddle which displaces to one side as can be seen in video (A). The third marker up from the top of the tail is the middle of the cantle, during locomotion, the saddle consistently slips to the right every stride. Saddle slip is generally only present on one rein therefore, a saddle which slips to the right will occur on the left rein and a saddle which slips to the left will occur on the right rein. If a saddle slips left and right, it is likely that the saddle is too wide therefore, saddle width should be checked by a saddle fitter. 


What effect does this have on the horse?

Video A - it can be seen that the left side of the saddle panel is brought up close to the midline of the horse (spine). This results in increased saddle pressures on the left side of the horse’s back, compressing the back muscles on the left. The horse’s limbs (front+hind) are loaded asymmetrically as a result of the asymmetric positioning of the saddle+rider.


What effect does this have on the rider?

Video A - the rider’s pelvis slips to the right (with the saddle), as a result, their upper body then shortens to the left, the rider’s left knee becomes tight and the right leg becomes straight. This is often easy to see, as the stirrup (on the side that the saddle has slipped too) “appears” to be longer however, this is a function of saddle slip not an asymmetry in the rider’s limbs or stirrup leathers. Lastly, rider’s may have an asymmetric rein tension, as a result of the rider trying to maintain stability.

As mentioned, saddle slip is generally only present on one rein, therefore all of the ridden work on that rein will be compromised – straight line, circling, half pass, jumping turns etc.


Correcting Saddle Slip

When saddle slip was corrected (video B – same horse/rider/saddle/day) you can see that the third marker is now aligned with the tail marker. When saddle slip was corrected, a more uniformed pressure distribution and symmetrical movement of the horse was found and a more symmetrical rider position along with an even rein tension.


Why does saddle slip occur?

There are multiple factors that influence saddle slip, there is evidence that saddle slip occurs as a result of lameness (Greve and Dyson, AHT/RVC). Saddle slip can also occur in non-lame horse’s (MacKechnie-Guire et al, . RVC). What is interesting, from our studies and others, saddle slip appears to be initiated by the horse and not the rider. Riders will follow the movement of the saddle but don’t necessarily cause the saddle to slip – more on that in another post. Research groups are investigating additional factors which could cause saddle slip – more on that in due course. 


Horses seek a locomotor pattern to alleviate any discomfort caused by a saddle. In this case, how can a saddle which is slipping to one side be of benefit to the horse? This locomotor pattern, can lead to increased asymmetry in the horse and rider, coupled with the asymmetric forces creates a vicious circle. 

I am a huge advocate of working as a team, therefore, in cases where saddle slip is present, it is essential that this is discussed with the acting saddle fitter in conjunction with the veterinarian, coach, equine/human physio, farrier, biomechanist, therapist etc. Saddle slip requires a team approach with regular saddle assessments to monitor progress etc. 

I hope the above notes are useful.

Please share to create awareness of the importance of addressing saddle slip AND help with saddle slip recognition, as in cases where the saddle is straight and then starts to slip could be used as an early indicator of movement asymmetry occurring!

Next post will be how to identify saddle slip and who is the primary cause – horse or rider!

Kind Regards  


Centaur Biomechanics

Dr. Russell MacKechnie-Guire