Diagnostic criteria for equine thoracolumbar myofascial pain syndrome

To help clarify the paper, and in particular the “jump sign” here is a explanation:

A jump sign is a sudden, involuntary whole‑body or regional movement the horse makes when a painful trigger point is pressed. It is essentially the horse “jumping away” from the examiner’s fingers because the palpation elicits a sharp, localized pain. In horses, a jump sign may present as:
A sudden flinch, jerk, or whole‑body twitch
A rapid drop or rise of the back
Stepping away from the examiner
Tensing or bracing the musculature
Occasionally a behavioral reaction (ears back, tail swish)

The jump sign is considered a robust marker of clinically significant myofascial pain, because:
It is highly correlated with pain severity
It is predictive in multivariate models
It helps differentiate true trigger point pain from mild sensitivity
In human MPS diagnostics, the jump sign is also a core criterion—this study essentially confirms its relevance in horses.

The jump sign and the hypersensitive spot are related but they are not the same thing. Core difference
Hypersensitive spot
A hypersensitive spot is a palpable point within a taut band that is painful when pressed.
It is a local sensory finding — the horse shows pain, but the reaction stays localized.
The study reports that every horse had a hypersensitive spot .

Jump sign
A jump sign is a whole‑body or large‑region reaction when that painful spot is pressed.
It is an involuntary movement — the horse flinches, jerks, drops the back, or steps away.
The study found the jump sign in 71.7% of horses and identified it as the dominant pain predictor (>90% importance) .
DrO

Diagnostic criteria for equine thoracolumbar myofascial pain syndrome: A foundational study
Res Vet Sci. 2026 Jun 27:210:106314. doi: 10.1016/j.rvsc.2026.106314. Online ahead of print.
Authors
María Resano-Zuazu 1 , Jorge U Carmona 2 , César Fernández-de-Las-Peñas 3 , David Argüelles 4
Affiliations

1 Department of Animal Medicine and Surgery, School of Veterinary Medicine, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain.. Electronic address: z42rezum@uco.es.
2 Grupo de Investigación Terapia Regenerativa, Departamento de Salud Animal, Universidad de Caldas, Calle 65 No 26-10, 170004 Manizales, Colombia.. Electronic address: carmona@ucaldas.edu.co.
3 Department of Physical Therapy, Occupational Therapy, Physical Medicine and Rehabilitation, Universidad Rey Juan Carlos, Avenida de Atenas s/n, 28922 Madrid, Spain.. Electronic address: cesar.fernandez@urjc.es.
4 Department of Animal Medicine and Surgery, School of Veterinary Medicine, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain.. Electronic address: cu2arcad@uco.es.

PMID: 42372589
DOI: 10.1016/j.rvsc.2026.106314

Abstract

Diagnostic criteria for myofascial pain syndrome (MPS) are well established in humans but remain underexplored in horses. This study aimed to identify which MPS clinical signs were present in the equine thoracolumbar region, assess internal coherence among clinical indicators, and explore the diagnostic relevance of owner-reported behavioural, signalment, management, and clinical variables. A population of 120 horses underwent a static physical assessment of the thoracolumbar region. Owner-reported horse behaviours were collected through a questionnaire. Taut band, hypersensitive spot, local twitch response (LTR), jump sign, restricted range of motion (ROM), pain score (0-5), and global ROM score (0-4) were assessed by manual palpation. Machine-learning (ML) regression models were used to examine multivariate predictive patterns. A taut band and a hypersensitive spot were present in all horses, whereas an LTR was absent. The jump sign was identified in 71.7% and restricted ROM in 69.2% of horses. The median pain score was 4 (IQR 3-4, range 2-5). Jump sign correlated with pain score (ρ = 0.814, p < 0.001), and restricted ROM correlated with global ROM score (ρ = 0.749, p < 0.001). Owner-reported behaviours had a weak relationship with pain on palpation (ρ = 0.218, p = 0.017). Stabled horses had higher pain scores (p = 0.044) and greater ROM restriction (p = 0.013) than horses kept outdoors. Machine learning identified the jump sign as the dominant pain predictor (>90% importance) and a robust clinical marker. Taut band, hypersensitive spot, and jump sign emerged as key clinical findings associated with equine thoracolumbar MPS, providing novel insights into the clinical variables characterising this condition in horses.

Keywords: Artificial intelligence; Back pain; Horse; Muscle; Palpation; Trigger points.

Copyright © 2026 Elsevier Ltd. All rights reserved.
Conflict of interest statement

Declaration of competing interest The authors declare that they have no competing interests.

• This topic was modified 49 minutes ago by Robert Oglesby DVM.
• This topic was modified 48 minutes ago by Robert Oglesby DVM.