Numerous studies have investigated the influence of pain on the spatial distribution of muscle activity using high-density surface electromyography (HDsEMG) to understand pain-related motor adaptations in individuals with spinal pain. This systematic review aimed to synthesize the available evidence to determine whether clinical or experimental spinal pain influences the spatial distribution of muscle activity. The review protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42024524021, registered April 03, 2024). Electronic databases (MEDLINE, EMBASE, PubMed, CINAHL Plus, and Web of Science), grey literature, and key journals were searched from inception to April 4, 2025. Two independent reviewers screened studies and assessed the quality of studies using the Newcastle-Ottawa Scale and the Consensus for Experimental Design in Electromyography (CEDE) checklist. Data synthesis was conducted by outcome domain, and random-effects meta-analyses were performed when feasible. From 1,099 records, 23 studies (15 clinical pain, 8 experimental pain) met the inclusion criteria. The overall certainty of evidence was rated very low according to GRADE. Meta-analysis showed a cranial shift of erector spinae activity in clinical low back pain (SMD = -0.64 [95%CI: -0.97; -0.32], p = 0.0001, I2 = 15.4%, τ2 = 0.085), although this effect was not robust in sensitivity analyses of functional tasks. In experimentally-induced neck pain, a caudal shift of upper trapezius activity was identified (SMD = 1.17 [95%CI: 0.61; 1.73], p < 0.0001, I2 = 33.4%, τ2 = 0.3059). Further studies using more consistent and comparable methodologies are needed to draw more definitive conclusions.

High-intensity interval training (HIIT) and continuous endurance exercise (END) induce distinct neuromuscular adaptations, with END particularly enhancing fatigue resistance during sustained submaximal contractions. However, the motor unit (MU) mechanisms underlying these effects remain unclear. This study investigated MU firing adaptations associated with changes in time to task failure following END and HIIT. Sixteen healthy men were randomly assigned to END or HIIT (n = 8/group) and completed six sessions over 14 days. HIIT involved 8-12 × 60-s intervals at 100% peak power output, separated by a 75-s recovery; END involved 90-120 min of continuous cycling at ∼65% peak oxygen uptake (V̇o2peak). Before and after training, participants performed a nonfatiguing isometric contraction at 50% maximal voluntary contraction (MVC), followed by a sustained contraction at 30% MVC until failure, while high-density surface EMG signals were recorded from the vasti muscles. Signals were decomposed, and MUs were tracked across sessions. MU firing rates displayed a biphasic response to fatigue: an initial decline (first phase) followed by a later increase (second phase). Postintervention, only the END group increased time-to-task failure and delayed the onset of the second phase (P = 0.021), which correlated with time to failure (r = 0.70). The END group also showed less attenuation in firing rate at failure (50% vs. 30% MVC difference: END = 0.56 Hz; HIIT = 2.8 Hz; P = 0.011), which was also associated with total endurance time (r = 0.72). These findings suggest that END-induced fatigue resistance is associated with specific MU firing adaptations that enhance the central nervous system's ability to optimise MU recruitment and firing dynamics during fatigue development.NEW & NOTEWORTHY Two weeks of endurance training (END), but not high-intensity interval training (HIIT), prolonged time to task failure during sustained submaximal contractions. This improvement in performance was linked to distinct motor unit adaptations, delayed discharge rate increase, and reduced firing rate attenuation that explained ∼50% of performance gains. Short-term END thus elicits unique neuromuscular changes that enhance fatigue resistance at low-to-moderate intensities.

Abstract Research on age-related changes in trunk extensor force control is currently limited, and the underlying neuromuscular mechanisms remain largely unexplored. To address this, we examined the relationship between oscillations in lumbar erector spinae (LES) activity and torque fluctuations in 20 young and 20 older adults during isometric and isokinetic (concentric) trunk extension contractions at 25% and 50% of maximal voluntary contraction (MVC). High-density surface electromyography (HDsEMG) signals were recorded bilaterally from the LES using 64-electrode grids. Torque steadiness was quantified using the coefficient of variation (CoV) of torque. Coherence analysis in the δ band (0–5 Hz) was applied between filtered interference HDsEMG and torque signals. Topographical maps were also generated to assess regional differences in HDsEMG-torque coherence. Older individuals exhibited greater torque CoV than young adults during both isometric (+ 23.03%, p < 0.001) and isokinetic (+ 72.62%, p < 0.001) contractions, with a larger between-group difference at 25% MVC for isokinetic contractions (Group × Torque interaction; p = 0.007). At this intensity, the older group also showed reduced HDsEMG-torque coherence (Group × Torque interaction; p = 0.004). During isometric contractions, coherence magnitude was similar across groups (p > 0.05), but older adults exhibited higher coherence in more cranial and medial LES regions (p = 0.005 and p = 0.001, respectively). Older individuals exhibited the greatest impairment in force steadiness during low-intensity isokinetic contractions. Distinct neuromuscular patterns, possibly influencing force control, emerged depending on contraction type.

Cervical radiculopathy (CR) is a neuropathic condition characterized by heterogeneous clinical presentations affecting musculoskeletal, neurological, and psychological domains. The variable success of CR management may result from a limited consideration of this complexity and a mismatch between treatment strategies and the predominant pain mechanisms, often overlooking the presence of nociplastic pain features. This cross-sectional study aimed to examine the relationships among clinical, musculoskeletal, neurological, and psychological features in patients with CR using a network analysis, and to identify patient subgroups with distinct clinical profiles, specifically testing for the presence of features characteristic of nociplastic pain. A cohort of patients with CR was assessed using validated measures across the musculoskeletal, neurological, clinical, and psychological domains. Network analysis was performed to determine the most influential variables and their interconnections. Cluster analysis was conducted to identify subgroups based on symptom profiles. Network analysis revealed that disability was the most central variable, directly associated with self-efficacy, fear avoidance, pain severity, and cervical mobility. Cluster analysis identified three clusters along a continuum of severity. The most severe cluster, representing ∼25% of the cohort, exhibited a complex and mixed profile with the highest disability, pain, psychological distress, multisite pain, sleep disturbances, musculoskeletal impairments, and widespread sensorimotor alterations; all features characteristic of nociplastic pain. Disability is a key factor in the experience of CR, and the existence of a patient subgroup with a complex presentation and nociplastic features highlights that effective management of CR requires a personalised, multimodal approach that directly targets the main drivers of disability. PERSPECTIVE: This study integrates network and cluster analyses to understand the relationships between clinical, musculoskeletal, neurological, and psychological factors in cervical radiculopathy. Disability was the central, bridging variable across domains. The presence of a cluster with features characteristic of nociplastic pain supports the need for multimodal, mechanism-based management of cervical radiculopathy.

OBJECTIVES:This study aimed to evaluate pain distribution in people with acute whiplash-associated disorders (WAD) and to explore its association with neuropathic pain and assumed central sensitization features. Although widespread pain is common after a whiplash injury, the relationship between pain extent (the area of the body perceived as painful) and underlying pain-related mechanisms in acute WAD remains poorly understood. METHODS:In this cross-sectional study, 124 individuals (mean age: 39.7±11.2 y; 67 females) with acute WAD grade II (7 to 30 d post-injury) completed questionnaires assessing neck pain intensity, disability, neuropathic pain (S-LANSS), and assumed central sensitization (Central Sensitization nventory, CSII). Pain drawings were analyzed with a validated image-processing algorithm to quantify pain extent. Correlation and multiple linear regression analyses were performed to identify predictors of pain extent. RESULTS:Bivariate correlations showed that pain extent was significantly associated with all clinical variables, with the strongest correlation observed between pain extent and S-LANSS (ρ=0.816, P <0.001). In the multiple regression model, only S-LANSS was a significant predictor of PE (β=0.705, P <0.001), explaining 64% of the variance. A moderate correlation (ρ=0.437) was found between CSI and pain extent, but the CSI did not independently predict pain extent. No statistically significnat sex differences were observed for any clinical variable. DISCUSSION:This is the first study to show a strong association between neuropathic pain features and widespread pain in people with acute WAD. These findings highlight the potential utility of assessing pain extent and neuropathic pain features to identify pain phenotypes early after injury, that may support more individualized treatment approaches.

ABSTRACT Objectives: To explore patients' and physiotherapists' perspectives on a snack-based physical activity (PA) approach and mobile health technologies (mHealth) for non-specific chronic low back pain (NSCLBP). Snack-based PA refers to short, frequent bouts of activity (2-5 minutes) integrated into daily routines. Design: Qualitative study using Interpretative Phenomenological Analysis (IPA) of semi-structured online interviews. Setting: Community-based recruitment in the United Kingdom. Interviews were conducted online via Microsoft Teams between May and November 2024. Participants: Sixteen participants were purposively sampled: eight adults with NSCLBP (lasting >=3 months in the previous year) and eight physiotherapists with >=2 years' experience managing people with NSCLBP. Results: Three shared themes were identified across both groups: (1) understanding the needs and requirements of PA; (2) perceptions of snack-based activity; and (3) factors influencing mobile health application use. Five subthemes were identified within themes one and three, together with two additional subthemes reported only by patients, relating to data sharing and technical issues. Both groups valued the time-efficiency and practical integration of snack-based activity, while highlighting the need for personalisation, age-appropriate content, accessibility and affordability. Conclusions: Physiotherapists and patients emphasised the potential value of the snack-based PA approach in terms of adherence. However, both groups agreed that future intervention development should prioritise personalisation, user-friendly design, and equitable digital access. Keywords: Low Back Pain; Chronic Pain; Exercise; Physical Activity; Qualitative Research; Mobile Applications; Telemedicine; Patient Compliance; Physical Therapists; Snack-based Physical Activity. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Science, Technology, Engineering and Mathematics Ethics Committee of the University of Birmingham gave ethical approval for this work (reference ERN_1890-Apr2024). All participants provided written informed consent. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors.

BACKGROUND:There is limited evidence on the physical and psychological features present during remission from non-specific neck pain, yet this may be relevant for the high incidence of neck pain recurrence. METHODS:A cross-sectional study design was conducted with 60 participants (20 per group: healthy controls, people in remission from recurrent neck pain, current chronic neck pain) who were assessed for pressure pain thresholds, conditioned pain modulation, cervical kinematics, proprioception, neck muscle strength, neck muscle activity via electromyography, force steadiness, endurance, and psychological features. RESULTS:People in remission and those with current neck pain demonstrated reduced maximal velocity (p ≤ 0.05) and smoothness of movement (p ≤ 0.05) during neck extension, rotation, and side flexion compared to controls. Shoulder shrug strength (p ≤ 0.001) was also reduced in both pain groups. Maximal angular velocity and smoothness of neck flexion movement, as well as peak neck extension strength, were reduced only in those in remission compared to controls (p ≤ 0.01). Those with current neck pain distinctively showed reduced neck flexion strength, reduced force steadiness during submaximal neck flexion and extension contractions, heightened antagonist coactivity, and less endurance for the neck flexors and extensors (p ≤ 0.05). CONCLUSION:Individuals in remission from neck pain exhibit some alterations in cervical kinematics, motor output and neuromuscular control resembling similar impairments to those with current chronic neck pain despite being pain-free. Such features may be relevant for pain recurrence, and this should be explored in future longitudinal studies. SIGNIFICANCE STATEMENT:This study identifies changes in physical function of the neck which are present in people with active chronic non-specific neck pain that are also evident during remission from pain. Such findings provide an understanding of the previously underexplored clinical presentation during neck pain remission. If determined to be relevant, specific interventions to target these changes could be provided to optimise functional capacity with the aim of minimising or preventing the recurrence of pain.

To evaluate the effectiveness of a multimodal physiotherapy program compared with exercise programs on pain, disability, quality of life, and shoulder muscle activation in women with persistent pain following breast cancer treatment (PPBCT). Randomized, assessor-blinded, three-arm parallel-group clinical trial. Physiotherapy in Women’s Health Research Unit at the University of Alcalá, Madrid, Spain. Ninety women with PPBCT were recruited between April 2016 and April 2022. Participants were randomized into three groups (n = 30 each). All groups received six individual physiotherapy sessions over 6 weeks and the same pain education. Participants were allocated to (i) multimodal physiotherapy (MP) including scapular exercises, deep dry needling, and neurodynamic techniques, (ii) scapular exercises (SE), or (iii) conventional shoulder exercises (CSE). The primary outcome was shoulder pain intensity (VAS). Secondary outcomes included perceived shoulder pain and disability assessed with the Shoulder Pain and Disability Index (SPADI), health-related quality of life measured with the Functional Assessment of Cancer Therapy-Breast version 4 (FACT-Bv4), shoulder muscle activation assessed using surface electromyography, and myofascial pain syndrome evaluated according to Travell and Simons’ criteria. Ninety women were randomized and completed all follow-up assessments. All three groups showed improvements over time in most outcomes. Overall, the pattern of results favored MP, followed by SE and then CSE, with consistent superiority of MP across most outcomes and several time points. For the primary outcome, MP showed greater reductions in pain intensity than SE at all assessment points, with large between-group effects post-intervention and at 3 months, and a reduced effect at 6 months. Both MP and SE showed greater pain reductions than CSE at all assessment points, with large between-group effects, and changes exceeded the minimal clinically important difference only in the MP and SE groups. A multimodal physiotherapy program combining scapular exercises, deep dry needling, and neurodynamic techniques was more effective than exercise programs alone in women with PPBCT. Scapular exercise-based rehabilitation appears to play a key role in long-term recovery, while the addition of other physiotherapy techniques may primarily contribute to earlier symptom reduction. These findings support the use of a multimodal approach to address the complex mechanisms underlying persistent pain in breast cancer survivors, with potential implications for clinical decision-making in survivorship care. A multimodal physiotherapy approach integrating scapular exercises, pain education, deep dry needling, and neurodynamic techniques may provide clinically meaningful benefits for breast cancer survivors with persistent pain, improving function, quality of life, and long-term engagement in self-management strategies.

Abstract Pain demands attention and can disrupt task-related goals. Attention allocation is a key cognitive process supporting motor learning and disruption of internal schemas associated with attentional control during motor learning can result in interference in improvements in performance. Movement-contingent pain is an important characteristic of persistent musculoskeletal pain. Despite this, research exploring pain interference with motor learning and attention has exclusively utilised tonic pain paradigms. Understanding the impacts of movement-contingent pain on motor learning and attention may provide important insights into the interaction between pain and motor learning. The aim of this study was to; 1) explore the robustness of a movement-contingent pain paradigm across an extended period of training, 2) explore the impact of movement-contingent pain on improvements in performance and attentional allocation during motor learning. Three groups (healthy non-pain, healthy experimental-pain and persistent pain experimental-pain) completed ten trials of a motor sequence learning task while experiencing a movement-contingent electrical stimulation. Three task performance measures and five gaze indices, previously associated with attentional control, were collected. Results showed that; 1) low frequency electro-cutaneous stimulation could produce a valid and consistent pain experience across a sustained period of training, 2) attentional allocation becomes more efficient across learning, accompanied by improvements in task performance, 3) changes in task performance and attentional measures across training were similar in all groups despite the presence of pain, 4) movement-contingent experimental pain enhanced spatial performance at all time points in healthy participants but was not accompanied by a different pattern of attentional allocation. This study demonstrates that the impact of movement-contingent pain on motor learning is comparable to the impacts of tonic experimental pain and provides interesting insights into patterns of attentional allocation across time but little evidence that these attentional allocations are impacted by the presence of pain or a past history of pain.

BACKGROUND:Post-traumatic stress symptoms (PTSS) are common following musculoskeletal trauma and are associated with poorer recovery, disability, and reduced quality of life. Although psychosocial and injury-related factors have been linked to PTSS, limited research has examined longitudinal predictors or the relationship between injury severity and PTSS progression in people hospitalised for musculoskeletal trauma. OBJECTIVES:To identify predictors of PTSS at three and six months following musculoskeletal trauma and hospitalisation, and to examine the relationship between injury severity and PTSS severity over time. METHODS:This secondary analysis of a prospective cohort study included 125 adults admitted to a UK major trauma centre with acute musculoskeletal injuries. PTSS were assessed using the Impact of Event Scale-Revised (IES-R) at baseline, three, and six months, with scores ≥22 indicating elevated PTSS. Candidate predictors included socio-demographic, clinical, and trauma-related variables. Multivariate logistic regression identified predictors at three and six months. Multicollinearity was assessed using variance inflation factors and principal component analysis. Injury severity (mild, moderate, major) was examined using Kruskal-Wallis and Mann-Whitney U tests. Model discrimination and calibration were evaluated using AUC and Hosmer-Lemeshow tests. RESULTS:At baseline, 97.6% of participants met the PTSS threshold, decreasing to 26.4% at three months and 17.6% at six months. This high baseline prevalence likely reflects the early post-injury assessment period and the use of a sensitive screening threshold. At three months, road traffic accidents (OR 3.71, 95% CI 2.60-6.85) and car accidents (OR 2.20, 95% CI 1.68-3.15) significantly increased PTSS risk compared to falls. Higher baseline anxiety (OR 0.53, 95% CI 0.33-0.86) and kinesiophobia (OR 0.58, 95% CI 0.39-0.86) were associated with reduced PTSS odds. At six months, higher chronic pain-related disability independently predicted lower PTSS risk (OR 0.89, 95% CI 0.82-0.97). Injury severity differed significantly at six months (p = 0.022) but not at three months (p = 0.172). The six-month model demonstrated excellent discrimination (AUC = 0.91) and good calibration (p = 0.70). CONCLUSIONS:PTSS following musculoskeletal trauma are influenced by trauma mechanism, psychological factors, and injury severity over time, supporting early risk stratification and targeted psychological intervention.

Cervical radiculopathy (CR) is a clinical condition caused by compression of the nerve root. In clinical practice, the diagnosis of CR is based on information from the patient’s history, physical examination, and diagnostic imaging. This systematic review aimed to update and summarise the evidence reported in a systematic review published in 2018 on the diagnostic performance of physical examination tests. A literature search was performed in six electronic databases. Selection, assessment of risk of bias (using the QUADAS-2) and data extraction were performed independently by two reviewers. Sensitivity and specificity were calculated, and the certainty of the evidence was assessed using the GRADE framework. For the meta-analysis, a hierarchical bivariate random-effects model was used and, in line with recommendations for sparse data, models were interpreted as bivariate fixed-effect Generalized Linear Mixed Models. In total, eight studies were included. Diagnostic value was assessed for six physical examination tests. Slightly different versions of Spurling’s test were assessed in five studies, with a reported high specificity ranging from 0.84 to 1.00 (95

Introduction:The Cranio-Cervical Flexion Test (CCFT) is a validated clinical test used to evaluate deep cervical flexor muscle function. A pressure biofeedback unit (PBU) has traditionally been the reference device. Recently, a new portable digital device known as the Neuromuscular Cranio-cervical Device (NOD) has been developed as a potential alternative. Methods:In this cross-sectional concurrent validation study, 88 participants were recruited from four outpatient physiotherapy practices, including individuals with current neck pain and individuals with a previous history of neck pain. All participants performed the CCFT using both devices. The PBU was inflated to a baseline pressure of 20 mmHg, with the participant then performing C-CF to increase the pressure in increments of 2 mmHg over five progressive stages, while the NOD was calibrated to corresponding force targets. Agreement and concurrent validity between the devices were assessed, and C-CF range of motion (ROM) was analyzed using linear mixed-effects models. Results:Agreement between CCFT performance scores obtained with the NOD and the PBU was 94.3%, with a very strong positive correlation (Spearman's ρ = 0.930, p < 0.001). The NOD measured slightly greater C-CF ROM than the PBU (mean difference 0.68°), with significant differences at lower CCFT stages that converged at higher stages of the test. Conclusion:These findings demonstrate strong concurrent validity between the NOD and the PBU, supporting the NOD as a valid digital alternative for assessment of the CCFT.

Surface electromyography (sEMG) is one of the most widely used techniques for studying the control of human movement and neuromuscular function, and for establishing human-machine interfaces. Over the past two decades, sEMG has undergone substantial conceptual and methodological evolution, progressing from a tool for describing global muscle activation to a modality capable of providing access, directly or indirectly, to the neural information underlying motor control. Alongside advances in sensor technology, signal processing, modelling, and artificial intelligence, this evolution has expanded the range of questions that sEMG can address while also increasing the complexity of its correct interpretation. Despite the extensive literature on sEMG, fundamental misconceptions, recurring practical doubts, and fragmented understanding persist. In this article we adopt a question-driven format to address ten frequently asked questions (FAQs) on sEMG. The questions are organized into three thematic sections: foundations of sEMG, signal processing and interpretation, and applications. Rather than providing an exhaustive review, the answers focus on clarifying core principles, underlying assumptions, and intrinsic limitations, while highlighting recent methodological developments and future perspectives. By structuring the discussion around FAQs, this work aims to provide a clear, accessible, and conceptually grounded entry point to sEMG, and to establish a framework that can be extended in future contributions focused on specific application domains, complementing traditional narrative reviews and supporting more informed and effective use of the technique across research and applied contexts.

Abstract This study investigated the effects of eccentric exercise-induced delayed onset muscle soreness (DOMS) on neck extensor muscle behaviour and force output, examining force steadiness and the spatial distribution of splenius capitis (SCap) and upper trapezius (UT) muscle activity. Twenty healthy individuals completed three laboratory sessions (baseline, 24 h and 48 h post-exercise), where participants performed submaximal isometric neck extension and flexion tasks (20%, 50%, and 70% of their maximum voluntary contraction). High-density surface electromyography was used to examine bilateral SCap and UT muscle activity, and force steadiness was evaluated using the absolute and relative amplitude of force fluctuations. Neck muscle soreness significantly increased 24 h and 48 h post-exercise compared with baseline (p < 0.001), along with significant reductions in pressure pain thresholds over suboccipital and C4 regions (p < 0.001). Caudal shifts of SCap and UT muscle activity were observed during neck extension contractions in the presence of DOMS (p < 0.01, p < 0.001, respectively), and entropy values were significantly higher at 24 h and 48 h for the SCap (p < 0.001). The absolute amplitude of force fluctuations during the neck extension contractions improved across sessions (p < 0.05). These findings suggest that acute neck muscle soreness induces a redistribution of neck muscle activity; this is likely to be adaptive to protect painful muscle regions.

Objective Trismus is a common and debilitating complication following head and neck cancer treatment, with significant consequences for quality of life, nutrition and oral function. Although several rehabilitation strategies have been proposed, their design and effectiveness remain poorly systematized. This review aimed to summarize evidence from randomized controlled trials on rehabilitation interventions for treatment-induced trismus in HNC.Data sources A scoping review was performed using PubMed, PEDro, Web of Science, Scopus and EMBASE, covering publications up to May 2025.Review methods We included randomized controlled trials in English or Spanish evaluating any rehabilitation intervention in adults with trismus following HNC treatment. One author conducted the search, and two authors independently screened articles for inclusion.Results From 2215 records identified, 25 randomized controlled trials met the inclusion criteria. Twelve investigated preventions during or shortly after cancer treatment, while 13 addressed established trismus. Most interventions were based on exercise therapy, delivered in hospitals, private clinics or at home. Only a minority incorporated manual therapy or physical agents. Devices such as TheraBite or JawTrainer were evaluated in several studies. While most trials reported improvements in maximal mouth opening, few assessed condition-specific patient-reported outcomes. Rehabilitation interventions were predominantly implemented by physiotherapists.Conclusion Exercise therapy, often combined with devices, is the most frequently studied approach for treatment-induced trismus. Evidence for manual therapy and physical modalities remains limited. Considerable heterogeneity across studies hinders comparison and replication, underlining the need for standardized protocols and outcomes in future trials.

BACKGROUND:Pain, including phantom limb pain (PLP), residual limb pain (RLP) and low back pain (LBP), is highly prevalent after lower limb amputation (LLA) and compromises quality of life. Although both pain and function have been studied extensively, methods of assessment and reporting vary, limiting comparability. A clearer overview of how these domains are measured and interrelated is needed to guide research and practice. OBJECTIVE:To synthesise evidence on how postamputation pain and functional outcomes have been assessed and reported in adults with LLA, and to examine reported relationships between pain and mobility/function. DESIGN:Scoping review guided by Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. DATA SOURCES:MEDLINE, Embase and PsycINFO (inception to 15 August 2025). ELIGIBILITY CRITERIA:Quantitative studies that measured pain and functional outcome in adults with LLA. DATA EXTRACTION AND SYNTHESIS:Two reviewers independently extracted study characteristics, pain measures and functional outcomes in Covidence; findings were narratively synthesised. RESULTS:Eighty-four studies were included. RLP (n=46), LBP (n=32) and PLP (n=28) were most frequently examined. Pain was mainly assessed by self-report scales; mobility was typically assessed by clinical tests and less often by biomechanical instrumentation. PLP was associated with altered gait and balance deficits; RLP with limited walking distance, asymmetric weight-bearing and reduced community participation; LBP with gait asymmetry, trunk-pelvis discoordination and increased energy cost of walking. CONCLUSIONS:Postamputation pain is often linked to reduced mobility and functional limitations. However, heterogeneous definitions and inconsistent methodology hinder synthesis across studies. Future research should combine validated pain scales with objective analysis, wearable sensors and musculoskeletal modelling to clarify mechanisms and inform rehabilitation.

Introduction Neck pain (NP) is a leading cause of disability worldwide and affects more than 200 million people. Incidence and associated economic burden are constantly increasing, and little is known about the factors that promote new and more severe episodes in those individuals with recurrent NP. Current evidence supports that changes in physical, psychological and social factors persist between NP episodes, and these changes might contribute to the development of new episodes. The End Recurrent Neck Pain (END-RNP) study aims to use physical, psychological and social factors tested while in symptom remission to predict, within a 12-month period, the frequency and severity of new NP episodes.Methods and analysis The END-RNP study is a multicentre, prospective cohort study conducted from March 2025 to February 2028 at the University of Birmingham and the University of Essex (UK). 300 adults reporting two or more NP episodes in the previous year will be recruited from September 2025 to form the recurrent NP cohort, and 48 adults without a history of NP will provide normative data. Laboratory testing will be conducted for all participants when pain-free by assessing cervical kinematics and proprioception, neck-muscle strength, endurance and activation, pain processing, psychological and social factors. All recurrent NP participants will complete online questionnaires every 2 weeks for 12 months, recording days with NP, pain intensity/interference, healthcare use and other behavioural and environmental factors. Participants in the recurrent NP cohort who experience an acute NP episode during the 12-month follow-up will repeat the laboratory assessment. To develop the prediction models, candidate predictors will be the baseline measurements of any feature that shows either cross-sectional differences between recurrent NP and control groups or within-subject changes between the pain-free baseline and a pain episode. From the identified candidate predictors, two multivariable models will be developed using penalised regression, with (i) number of days with NP (linear regression) and (ii) NP severity (ordinal regression) as their respective dependent variables. Internal validation will use bootstrap resampling to estimate optimism-adjusted performance (R2, C-statistic and calibration slope), prediction instability and uncertainty, and clinical utility. The models from the END-RNP study will provide clinical prediction tools to help identify those at high risk of frequent and severe NP episodes and to inform the personalised prevention of recurrent NP.Ethics and dissemination The END-RNP study was approved by the Ethics Committee at the University of Birmingham (ERN_4005-Aug2025) and by the University of Essex (ETH2526-0098) on 2 September 2025, prior to the recruitment of the first participant. The findings will be presented at national and international conferences and submitted for publication in peer-reviewed journals.

Background: Physical activity is a recommended first‑line treatment for chronic low back pain, yet adherence to structured exercise remains poor due to pain, fear, fatigue, and contextual barriers. Snacktivity™, which promotes brief, frequent bouts of movement embedded in daily routines, has emerged as a potentially feasible alternative. However, it remains unclear how, why, and for whom Snacktivity supports engagement in people living with chronic low back pain. Objective: To develop and refine programme theories explaining how Snacktivity‑type interventions support physical activity engagement and related outcomes in adults with chronic low back pain. Methods: A realist review was conducted following RAMESES standards. Initial programme theories were developed and iteratively refined through synthesis of quantitative, qualitative, and mixed‑methods evidence from Snacktivity and related sedentary‑reduction interventions in low back pain and transferable adult populations. Evidence was analysed to identify context–mechanism–outcome (CMO) configurations. Results: Forty‑two studies contributed evidence to programme theory refinement. Five refined programme theories were supported. Snacktivity appears to enable engagement by lowering perceived burden and threat rather than eliminating fear, generating mastery experiences that enhance self‑efficacy, and reducing symptom interference through brief, distributed activity. Education and coaching components supported meaning‑making by reframing movement as legitimate and achievable, while environmental cues and routines promoted habit formation. Psychosocial outcomes (confidence, mood, vitality) and habit formation were more consistently improved than performance‑based outcomes, and engagement was sustained even when pain or fatigue persisted. Conclusions: Snacktivity functions as a participation‑enabling intervention rather than a traditional exercise prescription. Its effectiveness in chronic low back pain is explained by psychosocial and contextual mechanisms that support psychological safety, mastery, and habit formation. These findings support a shift from dose‑response exercise models toward interventions that prioritise feasibility, meaning, and sustained participation in daily life.

BACKGROUND AND OBJECTIVE:Non-specific low back pain (LBP) frequently becomes persistent or recurrent. This systematic review and meta-analysis determined whether physical, psychophysical or psychological variables can predict persistent or recurrent non-specific LBP. DATABASE AND DATA TREATMENT:Studies investigating physical, psychophysical or psychological predictors of persistent/recurrent LBP, pain intensity or disability were included. MEDLINE, EMBASE, APA PsycINFO, PubMed, CINAHL Plus, Web of Science, Scopus, ZETOC and OpenGrey were searched until January 2025. Risk of bias of individual studies was assessed using QUIPS and the certainty of evidence using GRADE. RESULTS:Fifteen studies were included, all addressing persistent LBP, examining one physical predictor domain (trunk kinematics), one psychophysical predictor domain (pain sensitivity) and seven psychological domains (depression-distress, anxiety, fear avoidance, catastrophising, somatisation, pain coping strategy, pain self-efficacy). Depression and distress significantly predicted persistent LBP and disability (n = 15,778; β = 0.28, 95% CI: 0.04 to 0.53, p = 0.024), and fear avoidance also significantly predicted persistent LBP and disability (n = 1105; β = 0.24, 95% CI: 0.00 to 0.49, p = 0.049), albeit both with low certainty of evidence. Enhanced temporal summation of pain was not a significant predictor of pain outcomes (n = 192; β = 0.10, 95% CI: -0.37 to 0.57), with very low certainty of evidence. Physical predictors showed limited and inconclusive evidence. Overall, the certainty of evidence ranged from very low to low across all predictor domains. CONCLUSION:Psychological factors, particularly depression-distress and fear avoidance, may predict LBP persistence, although higher quality studies are needed. SIGNIFICANCE STATEMENT:Depression-distress and fear avoidance are significant predictors of persistent non-specific low back pain, while evidence for physical predictors remains limited. These findings emphasize the need for early identification of modifiable psychological risk factors. TRIAL REGISTRATION:PROSPERO (Registration number CRD42024599514).

Introduction Low back pain (LBP) is a global health concern. Approximately two-thirds of those who recover from LBP experience a relapse within a year, with many chronic cases encountering acute flare-ups (exacerbation). This systematic review will synthesise and analyse whether physical and/or psychological features can predict recurrent episodes of LBP or exacerbation of pain.Methods and analysis This systematic review protocol follows the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines. Comprehensive literature searches will be conducted in MEDLINE, EMBASE, APA PsycInfo, PubMed, CINAHL Plus, Web of Science, Scopus and ZETOC, spanning from each database’s inception through to January 2025. Google Scholar and grey literature sources, including OpenGrey, will also be searched to ensure comprehensive coverage. Two independent reviewers will screen titles, abstracts and full texts, assessing the risk of bias with a modified Quality in Prognosis Studies tool. The overall certainty of evidence will be evaluated using an adapted Grading of Recommendations Assessment, Development and Evaluation approach. If sufficient data homogeneity is present, a meta-analysis will be performed; otherwise, findings will be synthesised narratively. The results will identify the ability of physical and/or psychological factors to predict pain recurrence or acute exacerbation in case of persistent non-specific LBP.Ethics and dissemination This study protocol does not present any ethical concerns. The findings from the systematic review will be submitted for publication in a peer-reviewed journal and will also be presented at relevant conferences.PROSPERO registration number CRD42024599514.