Flexion tests used to evaluate horse soundness are controversial because they compress joints and may cause temporary pain to detect lameness, raising welfare questions about their diagnostic value.
Flexion tests deliberately cause temporary discomfort to horses by compressing joint structures, and the welfare justification depends on the diagnostic value of the information obtained. The poor specificity of flexion tests means many horses experience discomfort for a test with limited diagnostic utility. The subjective nature of assessment and variable technique between examiners further limits value. Welfare-positive lameness investigation should use the least invasive methods that provide the most reliable information. Advances in digital gait analysis, nerve blocking, and imaging offer increasingly objective alternatives that may provide superior diagnostic information with less welfare cost.