As rehabilitation therapists, assessing movement is a huge part of what we do. Lameness assessment is a part of the evaluation of movement, but it’s not the full picture. It’s a sign of pain and altered biomechanics rather than a diagnosis in itself.
Our role is to notice change, pattern, and persistence, then collaborate with the vet to localise pain and protect the horse from long-term harm. When evaluating lameness, we need to think baseline first: what you see at walk and trot before any manipulations or nerve blocks; and then what changes when a test or condition is introduced that exacerbates the lameness.
Concurrent and compensatory lameness: why one problem rarely travels alone
Horses often carry more than one pain site. Sometimes those sites are unrelated, but more often the second site develops because the first has distorted the horse’s movement for long enough to overload something else. That pattern typically begins as muscular pain and tension, then progresses toward joint or ligament inflammation, and – if we miss it – into structural change. Rapid identification of both primary and secondary pain protects the horse.
These compensatory patterns are predictable. You’ll commonly see bilateral fore or bilateral hind involvement, or a fore–hind pairing on the same or opposite side as load shifts during protection. The “why” is simple load mechanics: most horses carry ~60% of body weight on the forehand at rest (more with a rider), and discipline modifies this further – collected work and driving sports push load caudally, while canter and gallop concentrate forces onto a single forelimb during the stance phase.
Clinical guidelines help us avoid false trails in identifying the origin of a lameness.
In the forelimb, about 95% of primary pain sits at or below the carpus and the structures within the hoof remain the first suspect.
In the hindlimb, the structures within the hoof remain your primary suspects, with the hock following closely behind. Always evaluate the lumbosacral and sacroiliac region as 80% of hindlimb lameness have concurrent pain in these areas. Riders (especially inexperienced ones) often perceive forelimb pain as a hindlimb problem – don’t be led there without evidence.
Flexion tests vs passive range of motion: not the same thing
Passive range of motion (PROM) is about evaluating range of motion, pain on manipulation, and joint end feel. Flexion tests are provocation tests: you hold one or more joints in flexion for a set time and immediately trot off to see how gait changes compared with the baseline gait. They’re especially useful for unmasking asymmetry when you suspect bilateral lameness that’s cancelling itself out visually.
We’re not vets, and we don’t diagnose – but understanding what a vet is trying to achieve with these tests (and what the tests can’t do) makes our assessments sharper and our referrals more precise.
How accurate are flexion tests?
Short answer: interpret with care. Flexion tests are not sensitive or specific.
In practice, that means lots of false positives (when the flexion test is positive but the horse is not lame), especially if the tester uses more force than intended, if the horse is in hard work, and even more so in sound older mares. Conversely, true negatives (when the flexion test is negative and the horse is not lame) are relatively reliable. False negatives (when the flexion test is negative but a lameness is present) are slightly more reliable.
Use flexion tests as signals that something is irritably load-sensitive today, not as locators of an exact structure.
Specificity breaks down because you can’t truly isolate one joint. Flexing a limb changes weight-bearing through the contralateral limb, increases forces through the sacroiliac joint and axial skeleton, and loads the soft-tissue slings anchoring the forelimb to the trunk. A “positive carpal flexion,” therefore, is not enough reason to assume the carpus is causing the lameness.
If (and when) you use them: consistency is everything
If you ever employ a simple flexion test pre-referral, standardise your method so your notes are meaningful to the vet. Use the same sequence, compare to the contralateral limb, flex for ~1 minute (45 seconds is usually enough), and aim for ~100 N of force – about what it feels like to lift 10 kg. Push much harder and you will provoke positives in normal horses; one study reported positives with 150–250 N. Trot immediately after release to assess sustained change beyond the first few strides.
What counts as “positive”? Either a new, obvious lameness, or a 1–2 grade increase over baseline that persists for more than 3–5 strides. Many clinicians ignore the first three strides after release to avoid over-calling transient stiffness. Record what you saw, how long it lasted, and where you went next.
Why flexion hurts (and what each test is really stressing)
Flexion tests increase intra-articular pressure and subchondral bone load on the flexion side while stretching peri-articular soft tissues on the extension side. In other words, they compress what already doesn’t like compression and pull on what’s irritable when stretched. That’s why the same limb position can amplify pain in multiple structures – and why the result is a provocation sign, not a localisation tool.
There are many variants – distal limb flexion, fetlock flexion, carpal flexion (this is likely the closest to isolating a joint that we get during flexion tests), proximal fore flexion or extension, proximal and full hind flexion tests.
We can also use wedge tests to evaluate the digit and associated tissues.
Static palpation can also be used by applying firm, direct pressure to a painful area and holding it for a period of time before repeating the gait assessment in the same way as a flexion test is performed. This is useful for splints and the suspensory branches.
All of these tests share the same interpretation caveat: false positives are common; note your finding and continue the evaluation or refer appropriately.
Concurrent lameness: quick pattern recognition in real life
The navicular-foot spectrum in the forelimb loves to hide bilaterally. Flexion may make things appear to be in the distal limb, but nerve blocks and hoof evaluation will decide whether the foot remains suspect number one – remember the ~95% rule for forelimb primary pain being at or below the carpus, with the internal hoof structures as the first suspect.
In dressage horses, a hindlimb primary lameness often creates forelimb loading that mimics a lameness. Evalaute the canter and sit phase carefully: collection shifts load caudally, predisposing to hindlimb problems that can create contralateral or ipsilateral forelimb signs. Positive proximal hind flexion may direct the vet toward a suspensory vs. a hock work-up, but it’s still a pointer and not the whole picture.
Pain or dysfunction within the lumbosacral and sacroiliac region should point towards further investigation of the distal hindlimb. The connection between hindlimb pathology and pain in these regions is strong, and we need to identify the primary cause of dysfunction if we hope to facilitate healing and rehabilitation.
When to use (and when not to)
Where do flexion tests fit for us as veterinary rehabilitation therapists?
They’re most justifiable in a structured pre-referral screen when you need a quick, standardised snapshot to communicate to the vet, or when encountering a suspected bilateral lameness – with the understanding that interpretation must rest with the veterinarian.
Avoid flexion tests close to competitions due to potential lingering effects, and be mindful that testing immediately before treatment can confound your reassessment.
Take-home
Flexion tests are useful provocations, but they are not diagnostic. Standardise your method if you use them at all; note sustained, side-to-side changes; and never localise from a single positive. Above all, keep concurrent and compensatory patterns front-of-mind. When we integrate careful observation with disciplined note-taking and timely referral for veterinary work-up (including blocks and imaging), we help the horse sooner – and we spare secondary structures from becoming tomorrow’s problem.
References
1. Ross and Dyson, Diagnosis and Management of Lameness in the Horse, Second Edition, 2011, Elsevier
2. Desfontaines, B., Ovendale, T. 2025. Lameness Introduction: Equine Pathology & Surgery [Lecture to EPS226]. Equine-librium College, Plettenberg Bay, 2025.
3. OpenAI. (2025). ChatGPT [Large language model]. https://chat.openai.com/chat
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