Acute Modulation of Lumbar Motor Unit Behavior During Experimentally Induced Low Back Pain: A Motor Unit Decomposition Analysis
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Le résumé fourni par la source
BACKGROUND AND PURPOSE: Acute low back pain is a prevalent musculoskeletal disorder that can disrupt motor control and compromise functional stability. Evidence suggests that pain alters motor unit discharge characteristics and the temporal organization of muscle activation; however, the specific neuromuscular adaptations associated with acute low back pain remain insufficiently understood. This study aimed to investigate the effects of experimentally induced acute low back pain on force steadiness and motor unit discharge characteristics (including recruitment threshold, motor unit firing rate, and action potential amplitude) during a sustained spinal extension task METHODS: Thirty-three healthy participants (aged 18-40 years) performed a sustained spinal extension task at 20% of their maximum voluntary contraction under two experimental conditions: pre- and during pain induced by hypertonic saline injection, and pre- and during-isotonic saline injection into the right lumbar region. Electromyography signals were recorded bilaterally from the longissimus muscles. Signals were decomposed into individual motor unit action potential trains using advanced algorithms and clustered using the K-means method. RESULTS: The hypertonic saline injection successfully induced moderate pain on the numerical pain rating scale (NPRS) (median = 4.71; interquartile range (IQR) = 1.61), which was significantly higher than the isotonic control condition (NPRS median = 1.50; IQR = 1.00; p < 0.001). During the pain condition, significant lateralized adaptations were observed: motor units within the contralateral (left) longissimus muscle exhibited an increased firing rate (p = 0.020, r = 0.33), with no significant changes in the recruitment threshold or motor unit action potential amplitude. On the ipsilateral side, subtle modulations in recruitment threshold were detected. In contrast, the isotonic condition elicited only localized and nonsystemic neuromuscular changes, without the coordinated bilateral organization observed under acute pain. DISCUSSION: Acute low back pain induces a dynamic and lateralized modulation of motor unit recruitment, suggesting a compensatory redistribution of neural drive that may help preserve functional stability despite altered motor coordination. These findings provide novel insights into the neuromuscular adaptations underlying acute low back pain and have potential implications for physiotherapy assessment and intervention.
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Le contrôle bibliographique ouvert
DOI retrouvé dans Crossref DOI retrouvé ; titre concordant.
- Titre Crossref
- Acute Modulation of Lumbar Motor Unit Behavior During Experimentally Induced Low Back Pain: A Motor Unit Decomposition Analysis
- Date Crossref
- 01/07/2026
- Éditeur
- Wiley
- Type
- journal-article
Ce recoupement confirme des métadonnées liées au DOI. Il ne confirme ni la méthode ni les conclusions de l’étude, et il ne compte pas comme une seconde source scientifique indépendante.
Où se fait cette recherche
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Universidade do Porto pays non établi dans la noticeUniversité ou école supérieure
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Portuguese Army pays non établi dans la noticeOrganisme public
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Escola Superior de Saúde Norte da Cruz Vermelha Portuguesa pays non établi dans la noticeUniversité ou école supérieure
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Polytechnic Institute of Porto pays non établi dans la noticeUniversité ou école supérieure
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Universidade de São Paulo pays non établi dans la noticeUniversité ou école supérieure
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Polytechnic of Porto Porto Portugal Center for Rehabilitation Research (CIR) ESS pays non établi dans la noticeUniversité ou école supérieure
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Faculty of Sport University of Porto Porto Portugal Innovation and Intervention in Sport pays non établi dans la noticeUniversité ou école supérieure
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Northern School of Health Portuguese Red Cross Oliveira de Azeméis Portugal pays non établi dans la noticeUniversité ou école supérieure
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School of Arts Laboratory of Physical Activity Sciences pays non établi dans la noticeUniversité ou école supérieure
Universidade do Porto, Portuguese Army et Escola Superior de Saúde Norte da Cruz Vermelha Portuguesa, avec 6 autres affiliations.
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