Horses, just like people are more dominant on one side than another. This is often exacerbated by many owners and riders only working from the left hand side, particularly when leading and getting on and off. Symmetry can be described as parallel foot placement between the left and right side and in-line foot placement of the hind and front foot on the same side.
Recent studies have suggested that the human eye can only detect lameness if the horse is over 25% lame and there is often some discrepancy over which leg until the lameness gets to about 50%. Lameness is linked to riders who are asymmetric, but is also associated with non specific issues such as saddle slip, reluctant to go forward, etc etc. Unsurprisingly, 70% of horses with back problems are lame and 32% of lamenesses also present with back problems.
Further studies have identified that over 50% of horses which the owners thought were sound actually had a significant asymmetry which could have been classed as a lameness. Riders should think about how likely it is that your horse is asymmetric and possibly in the under 25% lame category. Things to think about:
- Is your horse always reluctant to move/yield in one direction, e.g. Left shoulder in, left canter?
- Does your horse box walk in one direction?
- Do you always tack up and get on the same way or are you good at switching your stirrup leathers and using a mounting block?
- Does your horse lack impulsion on one hind leg more than the other?
- How balanced and symmetrical are you? How dominant are you on your strong side? (Click here to find out how well you do on my 3-Part Rider Self Assessment)
Current lameness assessments by a vet will comprise of watching, feeling, stress testing, scanning and nerve blocking, as necessary.
Force plates are now being trailed in assessing lameness and have shown consistent findings:
- Less force can be produced by the affected leg which is shown by reduced power output and reduced peak force on that limb. This is identified as a lower spike on the y axis of a graph.
- Lameness/asymmetry will always cause compensations at the other end, e.g hind limb lameness will always cause a forelimb or neck asymmetry and forelimb lameness will always cause hind limb or sacrum asymmetry. This has been quantified by surface markers and video analysis.
- Trotting on the lunge will cause asymmetric force production due to centripetal forces (leaning in). The inner hip will move more but have reduced vertical movement during stance phase and reduced force production. This will look like an inside hip hike. Head movement varies between horses and can be greater during inside or outside forelimb stance. This is important because it would be easy to assume that all horses are now "asymmetric" when tested on the lunge, but it is merely how to horse has to carry himself to deal with the speed and radius of circle.
Thus, previously relying on only visual feedback to see if a horse is lame is becoming a thing of the past. Force plates, pressure mats and 3D optic systems as part of an Objective Locomotion Analysis are now able to act as a tool to contribute to a vet’s assessment.
However, riders need to vigilant in making sure that they are balanced and symmetrical as failure to do so is now scientifically linked to equine lameness. This is something, anecdotally, I have frequently found when treating horses. Several the patterns of tension and resistance in the horse is due to the rider. Having an MOT for you and your horse will provide greater insight into how you are both moving and influencing each other. For more information, please click on equine osteopathy or rider osteopathy, or have a look at some of the packages which I offer.