Exercise-induced changes in central sensitization outcomes in individuals with chronic musculoskeletal pain: A systematic review with meta-analysis.

BACKGROUND AND OBJECTIVE: Temporal summation of pain (TSP) and conditioned pain modulation (CPM) are the two most commonly used clinical measures of central sensitization (CS). However, the effectiveness of exercise on TSP and CPM has yet to be evaluated. This review aims to investigate the effect of exercise alone on CS outcomes in individuals with chronic musculoskeletal pain. DATABASES AND DATA TREATMENT: This is a systematic review and meta-analysis. MEDLINE, EMBASE, CINAHL, PEDro and Cochrane databases were searched. Data were extracted based on the exercise modality and grouped into aerobic, resistance, isometric, or motor control modalities. Risk of bias was assessed using RoB2, RoB2 for crossover trials and ROBINS-I tools. Quality of evidence was assessed using GRADE. Random-effects meta-analyses were conducted, with subgroup analysis conducted for each exercise modality. RESULTS: The meta-analyses included thirteen studies, consisting of eight non-randomized studies, three randomized controlled trials and three randomized crossover trials. Data were categorized into four subgroups for analyses based on exercise modality. No statistically significant effect existed for both TSP and conditioned pain modulation. However, motor control exercise was found to have a significant enhancing effect on conditioned pain modulation. No significant differences were found between the exercise subgroup for both TSP and conditioned pain modulation. CONCLUSIONS: We did not find an overall effect of physical exercise on TSP and CPM. However, subgroup analysis shows favourable effects of motor control exercise in individuals with chronic neck pain. Future research should focus on exercise modality and dosage and their role in the mechanism involved in TSP and CPM in predefined populations. SIGNIFICANCE STATEMENT: Results from this study found that motor control exercise has a significant enhancing effect on conditioned pain modulation, with subgroup analysis showing favourable effects of motor control exercise in individuals with chronic neck pain. This indicates that physical exercise may have a positive effect on central sensitisation in individual with chronic neck pain. However, differential effects may exist between different types of exercise. These findings will inform understanding of neurobiological effects underlying chronic neck pain and may guide the development of more effective, personalised treatments.

Effect of exercise on chronic neck pain and central sensitization: A protocol for a randomized crossover trial.

Exercise-induced hypoalgesia (EIH) has been found to vary widely within individuals with chronic neck pain (NP). Research has suggested that the presence of central sensitization within a subgroup of individuals with chronic NP might be a mediating factor to explain the relationship between exercise and improvements in patient-reported outcomes. Furthermore, recent work has found that lactate might play a role in the development and maintenance of chronic pain. The immediate effect of a single bout of physical exercise on central sensitization in individuals with chronic NP and the relationship between lactate concentration, central sensitization and pain sensitivity are to be investigated. Eighty adult participants with chronic NP will be recruited for this randomized crossover trial. Outcome measures, including temporal summation, conditioned pain modulation, EIH and lactate concentration, will be assessed before and after low- and high-intensity bicycling exercise. The outcomes of this study will provide new insights into the mechanistic effect of exercise on central sensitization in individuals with chronic NP and have the potential to add important information to the current exercise prescription guidelines for individuals with chronic NP. This study has been approved by the Human Research Ethics Committee, The University of Adelaide (H-2022-082) and registered in the Australian New Zealand Clinical Trials Registry (ACTRN12622000642785p).

Differences in the kinematics of the cervical and thoracic spine during functional movement in individuals with or without chronic neck pain: a systematic review.

BACKGROUND: Chronic neck pain is common, impacting a person's ability to complete functional tasks. One method of quantifying functional movement is three dimensional (3D) motion analysis, however, it is unknown whether it may detect alterations in movement kinematics in individuals with neck pain. OBJECTIVE: To systematically review studies to determine possible differences in cervical and thoracic kinematics during functional movement as measured by 3D motion analysis in individuals with neck pain compared to controls. DATA SOURCES: Medline, Amed, Scopus, Cochrane, Embase, CINAHL searched on 11/11/2017. STUDY SELECTION: Studies reported 3D kinematics of functional movement (based on real-world situational biomechanics, i.e., multi-planar movements) of the cervical and thoracic spine in individuals with and without neck pain. STUDY APPRAISAL AND SYNTHESIS: Two reviewers assessed study quality; studies were summarised using discussion. RESULTS: Four thousand four hundred and sixteen title/abstracts were screened, 11 full texts retrieved. Common reasons for exclusion were participants ≤8years of age and studies that did not investigate functional movement. Included studies (n=5) used 3D motion analysis to assess kinematics during functional tasks including typing, gaming and resting posture. Participants with neck pain displayed greater neck flexion postures, reduced head velocity and smoothness of movement. LIMITATIONS: Variations in measurement methods and participant samples prevented meta-analysis. CONCLUSION: Though few studies were identified, altered kinematics were observed in individuals with neck pain, suggesting further research examining cervical spine kinematics is warranted. Recognising kinematic differences is important for clinicians to identify possible movement risk factors in individuals with neck pain that may be targeted with treatment. SYSTEMATIC REVIEW REGISTRATION NUMBER PROSPERO: CRD42017076053.