Tests or procedures used by your vet to determine what is wrong with your horse, in order to reach a diagnosis.

Cost: $100 to $500

These cost ranges are approximate and may vary from region to region.
Additional charges may also apply.


Objective Lameness Evaluation, Inertial Sensor System

Cost: $100 to $500

These cost ranges are approximate and may vary from region to region.
Additional charges may also apply.


Lameness is described as an asymmetric gait, with many possible causes, the most common being pain somewhere in one or more limbs. Lameness historically has been detected through visual observation by the veterinarian. It has been shown in many studies that, even among experienced veterinarians, subjective detection of lameness can be insensitive and inaccurate, and agreement on the affected limb or limbs and severity is poor.

Assessing the results of diagnostic blocks and treatment is difficult in mild lameness and can be adversely affected by human bias. Multiple limb lameness further complicates observation and determination of the primary cause. Until recently, objective methods of measuring lameness had been restricted to gait analysis labs, impractical for day-to-day field use by veterinarians. An inertial sensor-based lameness measurement system allows veterinarians to accurately and repeatably measure lameness in the private practice clinics or farm calls.


When a horse is painful during weight-bearing, it alters its head and pelvic movements to transfer weight from painful limbs to less painful limbs. Equal weight-bearing on left and right limbs results in symmetric head and pelvic movement between the two halves of stride. Unequal weight-bearing produces asymmetric head (or pelvic) movement.

Body mounted inertial sensors measure the acceleration of the head and pelvis throughout the stride. A sensor on the RF pastern records the timing of the stride. As the horse trots, this information is transmitted wirelessly to a tablet computer that calculates the amount of asymmetry and analyzes for known and predictable patterns of lameness. The data from the device includes a graphical representation of stride-by-stride asymmetry and performs a statistical analysis of the severity and consistency of the measured lameness.

The system reports the limb or limbs affected, the amplitude of asymmetry (in millimeters), and the timing in stride (impact, mid-stance, or push-off) that the asymmetry is occurring.

Why A Vet Chooses This Diagnostic


Related Observations

Your vet might choose this diagnostic test if you were making these observations.

Very Common
Less Common
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Related Diagnostics

Other diagnostic tests that might be used in combination or with this one or instead of this one.

Very Common
Less Common
more diagnostics

Diagnoses Your Vet May Consider

This test could rule out or confirm any of the following diagnoses.

Very Common
Less Common
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Detects gait asymmetry and measures degree of asymmetry with better accuracy and sensitivity than even the most experienced practitioner.

Detects multiple limb lameness not obvious to the eye.

Can measure change in gait asymmetry (lameness) after diagnostic blocks have been performed.

Can measure and track change during or after treatment or rehabilitation, and quantify that change.

Can track subtle gait asymmetry over time. Can look for changes that might indicate an early problem.


This diagnostic does not determine the part of the limb that is painful. Your veterinarian still must perform the usual lameness evaluation protocols, which would usually include diagnostic nerve and joint blocks, in order to determine this.

If lameness is present on both left and right sides, but perfectly symmetrical left to right, then this system might not record the horse as lame The system will measure the difference between the two limbs, so if the lameness is of exactly the same amplitude and type (impact type or push off type), then there is a cancellation effect. Typically, however, one limb is a little worse than the other, and it will measure a mild lameness in the worse of the two limbs.

The system does not work for gaited horses. It must be used at the trot.

CONTRAINDICATIONS - This diagnostic is not recommended or needed for horses that are visibly lame at the walk. Exercise at the trot could worsen a condition causing severe lameness.

your role

Questions To Ask Your Vet:
  • How much will this examination add to the cost of my visit?
  • Do you think that this case warrants the use of inertial sensors (Objective lameness measurement)?
  • Does the device pinpoint lameness within the limb ?
  • Will the device work on my gaited horse?
  • Don’t you need sensors on all four limbs to determine lameness in the limbs?
  • Doesn’t having a sensor on only one limb cause a false forelimb lameness?
  • Why does it only evaluate the trot?
  • Why not the canter?
  • Can it be used while I ride my horse?
  • Does surface upon which the horse trots matter?
  • Does the size of my horse matter?
  • How does it handle high/low hoof pair conformation or different shoes on each forelimb?
  • I feel something is not right with my horse’s movement, but this says it is not lame. Why is that?
  • My horse doesn’t look or feel lame to me, why does it indicate that it is?

further reading & resources

Related References:

Rettig, MJ, Leelamankong, P, Rungsri, P, et al. Effect of sedation on fore- and hindlimb lameness evaluation using body-mounted inertial sensors. Equine Vet. J 2015 doi: 10.1111/evj.12463.

Keegan KG, Pai PF, Wilson DA, Smith BK. A curve-fitting technique for evaluating head movement to measure forelimb lameness in horses. Biomedical Sciences Instrumentation 36 (ISA [International Society for Measurement and Control volume 395]:239-244, 2000.

Donnell, J., Frisbie, D., King, M., Haussler, K., et. al. Comparison of subjective lameness evaluation, force platforms and an inertial-sensor system to identify mild lameness in an equine osteoarthritis model. The Veterinary Journal. Sep 2015

McCracken, M. J.; Kramer, J.; Keegan, K. G.; Lopes, M.; Wilson, D. A.; Reed, S. K.; LaCarrubba, A.; Rasch, M.; Comparison of an inertial sensor system of lameness quantification with subjective lameness evaluation. Wiley-Blackwell, Oxford, UK, Equine Veterinary Journal, 2012, 44, 6, pp 652-656, 20 ref.

Keegan, K. G. , Yonezawa, Y. , Pai, P. F. , Wilson, D. A. , Kramer, J. Evaluation of a sensor-based system of motion analysis for detection and quantification of forelimb and hind limb lameness in horses. American Journal of Veterinary Research, 2004, Vol. 65, No. 5, pp. 665-670, 21 ref.

Keegan KG, Yonezawa Y, Pai PF, Wilson DA. Telemeterized accelerometer-based system for the detection of lameness in horses. Biomedical Science Instrumentation 38 (ISA [International Society for Measurement and Control volume 419]:112, 2002

Marshall, J., Lund, D., Voute, L. Use of a wireless, inertial sensor-based system to objectively evaluate flexion tests in the horse. Equine Veterinary Journal. Dec 2012.

Maliye, S., Voute, L., Lund, D., Marshall, J. An inertial sensor-based system can objectively assess diagnostic anaesthesia of the equine foot. Equine Veterinary Journal. Dec 2013.

Keegan, K. G. , Arafat, S. , Skubic, M. , Wilson, D. A. , Kramer, J. Detection of lameness and determination of the affected forelimb in horses by use of continuous wavelet transformation and neural network classification of kinematic data. American Journal of Veterinary Research, 2003, Vol. 64, No. 11, pp. 1376-1381, 24 re

Rhodin, M., Roepstorff, L., French, A., Keegan, K., Pfau, T., Egenvall, A. (2016) Head and pelvic movement asymmetry during lungeing in horses with symmetrical movement on the straight. Equine Vet. J. 48, 315-320.

Author: Co-authored by Doug Thal DVM DABVP and Equinosis Staff