Physical activity should be the primary intervention for individuals living with chronic pain A position paper from the European Pain Federation (EFIC) 'On the Move' Task Force.

BACKGROUND: There is clear evidence demonstrating the benefits of physical activity (PA) on pain and overall health, however, PA is challenging for many individuals living with chronic pain. Even non-exercise specialists can (cost) effectively promote PA, but many health professionals report a number of barriers in providing guidance on PA, suggesting that it is not consistently promoted. This expert position paper summarizes the evidence and provides five recommendations for health professionals to assess, advise and support individuals living with any chronic pain condition with a long life expectancy in adopting and sustaining physically active lifestyles. METHODS: This position paper was prepared by the 'On The Move' Task Force of the European Pain Federation EFIC. Final recommendations were endorsed by the European Pain Forum, Pain Alliance Europe and the Executive Board of EFIC. RESULTS: We recommend that all health professionals (1) Take a history of the persons' PA levels, and put PA on the agenda, (2) Advise that PA is important and safe for individuals living with chronic pain, (3) Deliver a brief PA intervention and support individuals living with chronic pain in becoming physically active, (4) Discuss acceptable levels of PA-related soreness and pain and (5) Provide ongoing support in staying physically active. SIGNIFICANCE: Physical activity is safe and offers several advantages, including general health benefits, low risk of side effects, low cost and not requiring access to healthcare. Adoption of these recommendations can improve the quality of care and life of individuals living with chronic pain and reduce their overall health risks.

Preoperative glycaemic control, number of pain locations, structural knee damage, self-reported central sensitisation, satisfaction and personal control are predictive of 1-year postoperative pain, and change in pain from pre- to 1-year posttotal knee arthroplasty.

PURPOSE: The aim of this study was to identify preoperative predictors for 1-year posttotal knee arthroplasty (TKA) pain and pre- to post-TKA pain difference in knee osteoarthritis (KOA) patients. METHODS: From March 2018 to July 2023, this prospective longitudinal cohort study enrolled KOA patients awaiting TKA from four hospitals in Belgium and the Netherlands. Different biopsychosocial predictors were assessed preoperatively by questionnaires and physical examinations (input variables). The Knee injury and Osteoarthritis Outcome Score (KOOS) subscale pain was used to measure pain intensity. The absolute KOOS subscale pain score 1-year post-TKA and the difference score (ΔKOOS = 1-year postoperative - preoperative) were used as primary outcome measures (output variables). Two multivariable linear regression analyses were performed. RESULTS: Two hundred and twenty-three participants were included after multiple imputation. Worse absolute KOOS subscale pain scores 1-year post-TKA and negative or closer to zero ΔKOOS subscale pain scores were predicted by self-reported central sensitisation, lower KOA grade and preoperative satisfaction, and higher glycated haemoglobin, number of pain locations and personal control (adjusted R2 = 0.25). Additional predictors of negative or closer to zero ΔKOOS subscale pain scores were being self-employed, higher preoperative pain and function (adjusted R2 = 0.37). CONCLUSION: This study reports different biopsychosocial predictors for both outcomes that have filtered out other potential predictors and provide value for future studies on developing risk assessment tools for the prediction of chronic TKA pain. PROTOCOL REGISTRATION: The protocol is registered at clinicaltrials.gov (NCT05380648) on 13 May 2022. LEVEL OF EVIDENCE: Level II.

Does pain intensity after total knee arthroplasty depend on somatosensory functioning in knee osteoarthritis patients? A prospective cohort study.

The objective of this study is to determine whether the change in pain intensity over time differs between somatosensory functioning evolution profiles in knee osteoarthritis (KOA) patients undergoing total knee arthroplasty (TKA). This longitudinal prospective cohort study, conducted between March 2018 and July 2023, included KOA patients undergoing TKA in four hospitals in Belgium and the Netherlands. The evolution of the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale pain over time (baseline, 3 months, and 1 year post-TKA scores) was the outcome variable. The evolution scores of quantitative sensory testing (QST) and Central Sensitization Inventory (CSI) over time (baseline and 1 year post-TKA scores) were used to make subgroups. Participants were divided into separate normal, recovered, and persistent disturbed somatosensory subgroups based on the CSI, local and widespread pressure pain threshold [PPT] and heat allodynia, temporal summation [TS], and conditioned pain modulation [CPM]. Linear mixed model analyses were performed. Two hundred twenty-three participants were included. The persistent disturbed somatosensory functioning group had less pronounced pain improvement (based on CSI and local heat allodynia) and worse pain scores 1 year post-TKA (based on CSI, local PPT and heat allodynia, and TS) compared to the normal somatosensory functioning group. This persistent group also had worse pain scores 1 year post-TKA compared to the recovered group (based on CSI). The study suggests the presence of a "centrally driven central sensitization" subgroup in KOA patients awaiting TKA in four of seven grouping variables, comprising their less pain improvement or worse pain score after TKA. Future research should validate these findings further. The protocol is registered at clinicaltrials.gov (NCT05380648).

Mobile technologies for rehabilitation in non-specific spinal disorders: a systematic review of the efficacy and potential for implementation in low- and middle-income countries.

PURPOSE: The aim of this systematic review was primarily to identify the types of mHealth technologies for the rehabilitation of non-specific spinal disorders, second to evaluate their efficacy, and finally to determine their applicability in LMICs. METHODS: Three databases (Scopus, PubMed, and Web of Science) were searched for randomized controlled trials and clinical trials from January 2012 until December 2022. Studies were found eligible when using mHealth technologies for the rehabilitation of non-specific spinal disorders. To evaluate efficacy, the primary outcome was pain intensity, and the secondary outcomes were disability and quality of life. To evaluate the applicability in LMICs, information about financial and geographical accessibility, offline usability, and languages was extracted. RESULTS: Fifteen studies were included comprising 1828 participants who suffer from non-specific low back pain (86.05%) and non-specific neck pain (13.95%). Fourteen distinct smartphone-based interventions and two sensor system interventions were found, with a duration ranging from four weeks to six months. All mHealth interventions demonstrated efficacy for the improvement of pain, disability and quality of life in non-specific spinal disorders, particularly low back pain. Five of the evaluated smartphone applications were free of charge accessible and had language features that could be adapted for use in LMICs. CONCLUSION: mHealth interventions can be used and integrated into the conventional treatment of non-specific spinal disorders in rehabilitation. They have demonstrated efficacy and could be implemented in LMICs with minor adaptations to overcome language barriers and the absolute necessity of the internet.

High-Intensity Training for Knee Osteoarthritis: A Narrative Review.

Knee osteoarthritis (OA) is the most common joint disease worldwide. Exercise therapy has been identified as a first-line treatment option in patients suffering from knee OA. High-intensity training (HIT) is an innovative exercise modality with potential in improving various disease-related outcomes. The purpose of this review is to explore the impact of HIT on knee OA symptoms and physical functioning. A comprehensive search of scientific electronic databases was conducted to identify articles on the effects of HIT on knee OA. Thirteen studies were included in this review. Ten compared the effects of HIT with those of low-intensity training, moderate-intensity continuous training, or a control group. Three evaluated the effects of HIT alone. Eight reported a decrease in knee OA symptoms (especially pain), and eight reported an increase in physical functioning. HIT was shown to improve knee OA symptoms and physical functioning, but also aerobic capacity, muscle strength, and quality of life with minimal or no adverse events. However, compared with other exercise modalities, no clear superiority of HIT was found. HIT is a promising exercise strategy in patients with knee OA; nonetheless, the actual quality of evidence remains very low, and more high-quality studies are needed to confirm these promising outcomes.

High intensity training improves symptoms of central sensitization at six-month follow-up in persons with chronic nonspecific low back pain: Secondary analysis of a randomized controlled trial.

BACKGROUND: High intensity training (HIT) improves disability and physical fitness in persons with chronic nonspecific low back pain (CNSLBP). However, it remains unclear if HIT affects pain processing and psychosocial factors. OBJECTIVE: To evaluate 1) the effects of HIT on symptoms of central sensitization and perceived stress and 2) the relationship of symptoms of central sensitization and perceived stress with therapy success, at six-month follow-up, in persons with CNSLBP. METHODS: This is a secondary analysis of a previously published randomized controlled trial. Persons with CNSLBP (n = 51, age=43.6y) completed the Central Sensitization Inventory (CSI) and Perceived Stress Scale (PSS) at baseline (PRE) and six months after 12-week of HIT consisting of concurrent exercise therapy (FU). Two groups were formed based on CSI scores (low-CSI/high-CSI). First, linear mixed models were fitted for each outcome, with time and groups as covariates. Multiple comparisons were executed to evaluate group (baseline), time (within-group), and interaction (between-group) effects. Second, correlation and regression analyses were performed to evaluate if baseline and changes in CSI/PSS scores were related to therapy success, operationalized as improvements on disability (Modified Oswestry Disability Index), and pain intensity (Numeric Pain Rating Scale). RESULTS: Total sample analyses showed a decrease in both CSI and PSS. Within-group analyses showed a decrease of CSI only in the high-CSI group and a decrease of PSS only in the low-CSI group. Between-group analyses showed a pronounced decrease favouring high-CSI (mean difference: 7.9; 95%CI: 2.1, 12.7) and no differences in PSS (mean difference: 0.1; 95%CI: -3.0, 3.2). CSI, but not PSS, was weakly related to therapy success. CONCLUSION: HIT improves symptoms of central sensitization in persons with CNSLBP. This effect is the largest in persons with clinically relevant baseline CSI scores. HIT also decreases perceived stress.

Clinical phenotypes and prognostic factors in persons with hip osteoarthritis undergoing total hip arthroplasty: protocol for a longitudinal prospective cohort study (HIPPROCLIPS).

BACKGROUND: Large heterogeneity exists in the clinical manifestation of hip osteoarthritis (OA). It is therefore not surprising that pain and disability in individuals with hip OA and after total hip arthroplasty (THA) cannot be explained by biomedical variables alone. Indeed, also maladaptive pain-related cognitions and emotions can contribute to pain and disability, and can lead to poor treatment outcomes. Traumatic experiences, mental disorders, self-efficacy and social support can influence stress appraisal and strategies to cope with pain, but their influence on pain and disability has not yet been established in individuals with hip OA undergoing THA. This study aims (1) to determine the influence of traumatic experiences and mental disorders on pain processing before and shortly after THA (2) to identify preoperative clinical phenotypes in individuals with hip OA eligible for THA, (3) to identify pre- and early postoperative prognostic factors for outcomes in pain and disability after THA, and (4) to identify postoperative clinical phenotypes in individuals after THA. METHODS: This prospective longitudinal cohort study will investigate 200 individuals undergoing THA for hip OA. Phenotyping variables and candidate prognostic factors include pain-related fear-avoidance behaviour, perceived injustice, mental disorders, traumatic experiences, self-efficacy, and social support. Peripheral and central pain mechanisms will be assessed with thermal quantitative sensory testing. The primary outcome measure is the hip disability and osteoarthritis outcome score. Other outcome measures include performance-based measures, hip muscle strength, the patient-specific functional scale, pain intensity, global perceived effect, and outcome satisfaction. All these measurements will be performed before surgery, as well as 6 weeks, 3 months, and 12 months after surgery. Pain-related cognitions and emotions will additionally be assessed in the early postoperative phase, on the first, third, fifth, and seventh day after THA. Main statistical methods that will be used to answer the respective research questions include: LASSO regression, decision tree learning, gradient boosting algorithms, and recurrent neural networks. DISCUSSION: The identification of clinical phenotypes and prognostic factors for outcomes in pain and disability will be a first step towards pre- and postoperative precision medicine for individuals with hip OA undergoing THA. TRIAL REGISTRATION: ClinicalTrials.gov: NCT05265858. Registered on 04/03/2022.

Are contextual factors associated with activities and participation after total hip arthroplasty? A systematic review.

OBJECTIVES: After total hip arthroplasty (THA), over 30% of individuals report activity limitations and participation restrictions. This systematic review aimed to determine the association between contextual factors and outcomes in the activity and participation domain after THA for hip osteoarthritis (OA). METHODS: This systematic review was developed according to the PRISMA guidelines for systematic reviews. PubMed, Web of Science, Embase and Scopus were searched until August 2022. Risk of bias was assessed with the Quality in Prognosis Studies tool (QUIPS). RESULTS: Twenty-nine articles were included. Eighteen had a high risk of bias, 3 had a low risk of bias, and 8 had a moderate risk of bias. Anxiety was only investigated in studies with high risk of bias but showed a consistent negative association with activities and participation after THA across multiple studies. Evidence was inconsistent regarding the associations between depression, trait anxiety, sense of coherence, big 5 personality traits, educational level, marital status, employment status, job position, expectations and social support, and the activity and participation domain. Optimism, general self-efficacy, cognitive appraisal processes, illness perception, ethnicity, and positive life events were associated with activities and participation but were only investigated in 1 study. No associations were identified across multiple studies for living or smoking status. Control beliefs, kinesiophobia, race, discharge location, level of poverty in neighbourhood, negative life events and occupational factors, were not associated with the activity and participation domain but were only investigated in 1 study. CONCLUSION: Methodological quality of the included studies was low. Anxiety was the only factor consistently associated with worse outcomes in the activity and participation domain after THA but was only investigated in studies with high risk of bias. Further research is needed to confirm relationships between other contextual factors and activities and participation after THA. REGISTRATION: PROSPERO CRD42020199070.

Changes in static balance during pregnancy and postpartum: A systematic review.

BACKGROUND: Because pregnant women show a high risk of falling, some researchers examined their balance during static standing. This systematic review summarized the findings from all studies evaluating static balance in women during pregnancy and postpartum. RESEARCH QUESTION: Do pregnant and postpartum women show differences in static balance compared to non-pregnant women, and does static balance change during pregnancy and postpartum? METHODS: Pubmed, Embase, CINAHL, and Web of Science databases were searched systematically from inception until Feb 23, 2022. Studies were eligible for inclusion if they measured COP sway with a force plate during bipedal static standing, and compared COP outcomes between healthy pregnant or postpartum women and non-pregnant women, and/or during different stages of pregnancy and the postpartum period. Methodological quality was assessed overall with a modified version of the Downs and Black checklist, and specifically related to COP measurement by using recommendations of Ruhe et al. (2010). The protocol was registered in PROSPERO (CRD42020166302). RESULTS: Thirteen studies were included. Because methodological approaches varied greatly between studies, results were summarized descriptively. Studies reported either greater overall and anteroposterior COP sway magnitude, velocity and variability in women from the second half of pregnancy until six months postpartum compared to non-pregnant controls, or no differences in static balance. Changes in static balance throughout pregnancy were generally not found. Finally, there was no clear consensus on the influence of pregnancy on the reliance on visual inputs for balance control, and on whether differences in balance in pregnant and postpartum women reflect poorer balance or positive adaptations to the physical changes experienced during pregnancy. SIGNIFICANCE: Methodological heterogeneity between studies prevented us from drawing strong conclusions regarding the effect of pregnancy on static balance. Assessing the methodological quality of the studies revealed weaknesses that should be taken into account in future studies.

The Influence of Exercise Intensity on Psychosocial Outcomes in Musculoskeletal Disorders: A Systematic Review.

CONTEXT: Psychosocial parameters play an important role in the onset and persistence of chronic musculoskeletal disorders (CMSDs). Exercise therapy is a valuable therapeutic modality as part of CMSD rehabilitation. Hereby, exercise intensity is an important factor regarding changes in pain and disability in multiple CMSDs. However, the impact of exercise intensity on psychosocial outcomes remains poorly explored. OBJECTIVE: To identify the effects of different modes of exercise intensity on psychosocial outcomes in persons with CMSDs. DATA SOURCES: A systematic search was conducted up to November 2020 using the following databases: PubMed/MEDline, PEDro, Cochrane Library, and Web of Science. STUDY SELECTION: Studies reporting exercise therapy in CMSDs with a predefined display of exercise intensity and an evaluation of at least 1 psychosocial outcome were included. STUDY DESIGN: Systematic review. LEVEL OF EVIDENCE: Level 2a. DATA EXTRACTION: Data regarding demographics, exercise intensity, and psychosocial outcomes were included in a descriptive analysis. Methodological quality was assessed using the PEDro scale and Critical Appraisal Skills Programme (CASP) checklist. RESULTS: A total of 22 studies, involving 985 participants (with fibromyalgia, chronic low back pain, knee osteoarthritis, psoriatic arthritis, and axial spondyloarthritis) were included (mean PEDro score = 5.77/10). The most common psychosocial outcomes were quality of life (QoL) (n = 15), depression (n = 10), and anxiety (n = 9). QoL improved at any exercise intensity in persons with fibromyalgia. However, persons with fibromyalgia benefit more from exercising at low to moderate intensity regarding anxiety and depression. In contrast, persons with chronic low back pain benefit more from exercising at a higher intensity regarding QoL, anxiety, and depression. Other CMSDs only showed limited or conflicting results regarding the value of certain exercise intensities. CONCLUSION: Psychosocial outcomes are influenced by the intensity of exercise therapy in fibromyalgia and chronic low back pain, but effects differ across other CMSDs. Future research is necessary to determine the exercise intensity that yields optimal exercise therapy outcomes in specific CMSDs.

High Intensity Training Is an Effective Modality to Improve Long-Term Disability and Exercise Capacity in Chronic Nonspecific Low Back Pain: A Randomized Controlled Trial.

Previous research indicates that high intensity training (HIT) is a more effective exercise modality, as opposed to moderate intensity training (MIT), to improve disability and physical performance in persons with chronic nonspecific low back pain (CNSLBP). However, it is unclear how well benefits are maintained after intervention cessation. This study aimed to evaluate the long-term effectiveness of HIT on disability, pain intensity, patient-specific functioning, exercise capacity, and trunk muscle strength, and to compare the long-term effectiveness of HIT with MIT in persons with CNSLBP. Persons with CNSLBP (n = 35) who participated in a randomized controlled trial comparing effects of an HIT versus MIT intervention (24 sessions/12 weeks) were included for evaluation at baseline (PRE), directly after (POST), and six months after program finalization (FU) on disability, pain intensity, exercise capacity, patient-specific functioning, and trunk muscle strength. A general linear model was used to evaluate PRE-FU and POST-FU deltas of these outcome measures in each group (time effects) and differences between HIT and MIT (interaction effects). Ultimately, twenty-nine participants (mean age = 44.1 year) were analysed (HIT:16; MIT:13). Six participants were lost to follow-up. At FU, pain intensity, disability, and patient-specific functioning were maintained at the level of POST (which was significant from PRE, p < 0.05) in both groups. However, HIT led to a greater conservation of lowered disability and improved exercise capacity when compared with MIT (p < 0.05). HIT leads to a greater maintenance of lowered disability and improved exercise capacity when compared to MIT six months after cessation of a 12-week supervised exercise therapy intervention, in persons with CNSLBP.

The lumbar multifidus is characterised by larger type I muscle fibres compared to the erector spinae.

The metabolic capacity of a muscle is one of the determinants of muscle function. Muscle fiber type characteristics give an indication about this metabolic capacity. Therefore it might be expected that the lumbar multifidus (MF) as a local stabilizer contains higher proportions of slow type I fibers, compared to the erector spinae (ES) as a global mobilizer. The aim of this study is to determine the muscle fiber characteristics of the ES and MF to provide insight into their structural and metabolic characteristics, and thereby the functional capacity of both muscles. Muscle fiber type characteristics in the ES and MF were investigated with an immunofluorescence staining of the myosin heavy chain isoforms. In both the ES and MF, type I muscle fibers are predominantly present. The cross-sectional area (CSA) of type I muscle fibers is significantly larger in the lumbar MF compared to the ES. However, the mean muscle fiber type percentage for type I was not significantly different, which resulted in an insignificant difference in relative cross-sectional area (RCSA) for type I. No significant differences were found for all other muscle fiber types. This may indicate that the MF displays muscle fiber type characteristics that tend to be more appropriate to maintain stability of the spine. However, because we could not demonstrate significant differences in RCSA between ES and MF, we cannot firmly state that there are functional differences between the ES an MF based only on structural characteristics.

High Intensity Training to Treat Chronic Nonspecific Low Back Pain: Effectiveness of Various Exercise Modes.

High-intensity training (HIT) improves rehabilitation outcomes such as functional disability and physical performance in several chronic disorders. Promising results were also found in chronic nonspecific low back pain (CNSLBP). However, the impact of different exercise modes on HIT effectiveness in CNSLBP remains unclear. Therefore, this study evaluated the effectiveness of various HIT exercise modes and compared differences between these modes, on pain intensity, disability, and physical performance, as a therapeutic intervention for persons with CNSLBP. In a randomized comparative trial, consisting of a 12-week program, persons with CNSLBP were divided into four HIT groups, i.e., cardiorespiratory interval training coupled with either general resistance training, core strength training, combined general resistance and core strength training, or mobility exercises. Before and after the program, the Numeric Pain Rating Scale (NPRS), Modified Oswestry Disability Index (MODI), and Patient Specific Functioning Scale (PSFS) were recorded, and a cardiopulmonary exercise test (VO2max, cycling time) and isometric trunk strength test (maximum muscle torque) were performed. Eighty participants (mean age: 44.0 y, 34 males) were included. Improvements were found within all groups after the HIT programs and ranged from -39 to -57% on the NPRS, +27 to +64% on the MODI, +38 to +89% on the PSFS, +7 to +14% on VO2max, and +11 to +18% on cycling time. No differences between groups were found. High-intensity cardiorespiratory interval training improves CNSLBP rehabilitation outcomes when performed with other HIT exercise modes or mobility exercises. Hence, when setting up an exercise therapy program in CNSLBP rehabilitation, various HIT modes can be considered as therapy modalities.

Disability, kinesiophobia, perceived stress, and pain are not associated with trunk muscle strength or aerobic capacity in chronic nonspecific low back pain.

OBJECTIVES: To investigate to which extent disability, psychological and pain-related factors are associated with the outcomes of an isometric trunk muscle strength test and a cardiopulmonary exercise test in persons with chronic nonspecific low back pain (CNSLBP). DESIGN: Cross-sectional study. SETTING: REVAL Rehabilitation Research Center (Hasselt, Belgium). PARTICIPANTS: Persons with CNSLBP. MAIN OUTCOME MEASURES: Questionnaires concerning disability, patient specific functioning, kinesiophobia, perceived stress, pain intensity, and central sensitization were recorded. Outcomes of an isometric trunk strength test (maximum back and abdominal torque) and cardiopulmonary exercise test (VO2max) were assessed. Multivariate linear regression models determined factors explaining outcome variance. RESULTS: Data of 101 persons (39 males, mean age: 44.2y (SD = 9.6)) was assessed. Neither disability, nor psychological, nor pain-related factors were associated with the assessments. Variance in back muscle strength (R2 = 0.44, F = p < 0.01), abdominal muscle strength (R2 = 0.68, F = p < 0.01), and aerobic capacity (R2 = 0.76, F = p < 0.01) could only be explained through the included demographics covariates (age, gender, weight). CONCLUSION: This study highlighted the lack of biopsychosocial factors in explaining variance in outcomes of abdominal and back strength, and aerobic capacity in persons with CNSLBP with characteristics as depicted in the current sample. This information supports the valid interpretation of the outcomes of these assessments.

Biopsy samples from the erector spinae of persons with nonspecific chronic low back pain display a decrease in glycolytic muscle fibers.

BACKGROUND CONTEXT: Low back pain (LBP) in Western Europe was classified as having the highest disability and overall burden among 291 studied conditions. For an extensive period of time, evidence related to morphological changes (eg, atrophy and fat infiltration) of the paraspinal muscles in persons with LBP has accumulated. Despite this evidence, there is limited knowledge on muscle fiber type composition of these muscles, and their relation to LBP. PURPOSE: The aim of the study is to investigate differences in muscle fiber type composition between persons with nonspecific chronic low back pain (NSCLBP) and healthy controls for the lumbar erector spinae (ES) and multifidus (MF) muscle. STUDY DESIGN AND SETTING: A cross-sectional study took place in the REVAL Rehabilitation Research Center, Hasselt University, Diepenbeek, Belgium. PATIENT SAMPLE: Twenty persons with NSCLBP (age: 44.5±7.42) and 18 healthy controls (age: 39.89±7.90) participated in this study. OUTCOME MEASURES: The primary outcome measure was paraspinal muscle fiber type composition. Secondary outcomes consisted of physiologic measures (maximal aerobic capacity and back muscle strength) and functional measures (activity level). METHODS: Biopsy samples were taken from the lumbar ES and MF muscle at the L4 spinal level. These samples were stained using immunofluorescent antibodies against myosin heavy chains. In each sample, number and size (CSA) of type I, I/IIa, IIa, IIa/x, and IIx muscle fibers were quantified. From these data the relative cross-sectional fiber areas (RCSA) were calculated. To analyze differences in fiber type composition between healthy persons and persons with NSCLBP, a repeated measurements analysis of variance was used. Secondary outcome measures were analyzed using a Student's t test, and Wilcoxon test. This study was supported by the research fund of Hasselt University without potential conflict of interest. RESULTS: There were no significant differences between both groups regarding anthropometric data. There were no significant between group differences for CSA in the ES. Persons with NSCLBP displayed a nonsignificant (p=.0978) increase in the number of type I muscle fibers, and a significant decrease (p=.0019) in the number of type IIx muscle fibers in the ES muscle. Persons with NSCLBP also displayed a trend toward a higher (p=.0596) RCSA for type I fibers and a significantly lower RCSA for type IIx fibers (p=.0411). There were no significant between group differences within the MF. Regarding the secondary outcome measures, there was a significant between group difference in activity level (p=.0004) and isokinetic back muscle strength (p=.0342). CONCLUSIONS: This is the first study to examine muscle fiber type characteristics in both the ES and MF muscle of persons with NSCLBP. Based on muscle fiber characteristics, the paraspinal muscles of persons with NSCLBP seems to display a larger oxidative potential based on an increase of the number type I fibers at the expense of type IIx glycolytic fibers.

Exercise Intensity Matters in Chronic Nonspecific Low Back Pain Rehabilitation.

INTRODUCTION: Exercise therapy (ET) is advocated as a treatment for chronic nonspecific low back pain (CNSLBP). However, therapy effect sizes remain low. In other chronic disorders, training at higher intensity has resulted in greater improvements on both general health related and disease specific outcomes compared to lower-intensity ET. Possibly, high-intensity training also improves effect sizes in CNSLBP. OBJECTIVE: To compare the effects of a high-intensity ET program with a similar moderate-intensity ET program on disability, pain, function, exercise capacity, and abdominal/back muscle strength in persons with CNSLBP. METHODS: In a randomized controlled trial, persons with CNSLBP performed a 12-wk ET program (24 sessions, 1.5 h per session, twice per week) at high-intensity training (HIT) or moderate-intensity training (MIT). Questionnaires to assess disability (Modified Oswestry Index [MODI]), pain intensity (Numeric Pain Rating Scale), and function (Patient Specific Functioning Scale), a cardiopulmonary exercise test to assess exercise capacity (V˙O2max, cycling time), and a maximum isometric muscle strength test to assess abdominal/back muscle strength (maximum muscle torque) were administered at baseline and after the training program. RESULTS: Thirty-eight participants (HIT: n = 19, MIT: n = 19) were included (mean age, 44.1 yr, SD = 9.8, 12 males). Groups did not differ at baseline. Between group differences (P < 0.01) in favor of HIT were found for MODI, V˙O2max, and cycling time. Within group improvements (P < 0.01) were found in both groups on MODI (HIT:-64%, MIT:-33%), Numeric Pain Rating Scale (HIT, -56%; MIT, -39%), Patient-Specific Functioning Scale (HIT:+37%, MIT:+39%), V˙O2max (HIT:+14, MIT:+4%), cycling time (HIT:+18%, MIT:+13%), and back muscle strength (HIT:+10%, MIT:+14%). CONCLUSIONS: High-intensity training proved to be a feasible, well tolerated, and effective therapy modality in CNSLBP. Moreover, it shows greater improvements on disability and exercise capacity than a similar ET performed at moderate intensity.

Chondroid metaplasia of paraspinal connective tissue in the degenerative spine.

A 51-year-old male was routinely biopsied during a paraspinal muscle study. The biopsy sample was taken from the right erector spinae muscle at the fourth lumbar vertebra. The patient had no history of (diagnosed) major back trauma. The obtained sample was histologically analyzed (hematoxylin and eosin, safranin O), and complementary magnetic resonance imaging was performed. The biopsied sample contained chondroid tissue. Based on its location, the biopsy sample was appointed as chondroid metaplasia. Although chondroid metaplasia is not uncommon in humans, this is the first report of chondroid metaplasia within the paraspinal connective tissue. We propose a novel mechanism to explain the paraspinal chrondrogenic changes, related to spinal degeneration.

Reliability and agreement of isometric functional trunk and isolated lumbar strength assessment in healthy persons and persons with chronic nonspecific low back pain.

OBJECTIVES: to assess intra/inter-operator reliability and agreement of maximum isometric abdominal and back muscle strength in a functional trunk and isolated lumbar protocol, using an isokinetic dynamometer, in healthy persons and persons with chronic nonspecific low back pain (CNSLBP). DESIGN: Test-retest. SETTING: Participants performed two assessments consisting of two protocols on the Biodex 3 system, evaluating maximum isometric back and abdominal strength in a functional trunk and isolated lumbar position. During the first assessment, each protocol was executed twice, supported by different operators. PARTICIPANTS: Healthy persons (n = 20) and persons with CNSLBP (n = 20). MAIN OUTCOME MEASURES: Intraclass Correlation (ICC), Standard Error of Measurement (SEM and %SEM), and Minimal Detectable Change (MDC) of muscle strength outcomes and seat positioning characteristics were calculated. RESULTS: Intra/inter reliability of muscle strength outcomes was excellent (ICC: 0.94-0.98), while seat positioning characteristics varied from low to high (ICC: 0-0.94). For muscle strength outcomes, %SEM ranged from 4.7 to 9.2% and MDC ranged from 14.3 to 29.8 Nm in trunk flexion and 39.1-68.5 Nm in trunk extension. CONCLUSIONS: The Biodex 3 system can be used reliably to assess maximum isometric trunk muscle strength with the aforementioned protocols in healthy persons and persons with CNSLBP. All muscle strength outcomes showed comparable agreement (%SEM < 10%).

Feasibility, accuracy and safety of a percutaneous fine-needle biopsy technique to obtain qualitative muscle samples of the lumbar multifidus and erector spinae muscle in persons with low back pain.

The lumbar muscular system, in particular the lumbar multifidus muscle (LM) and the erector spinae muscle (ES), plays an important role in stabilizing and mobilizing the lumbar spine. Based on the topography, the lumbar paraspinal muscles can be classified into local and global muscles. LM is part of the local system, whereas ES is part of the global system. Therefore, it is interesting to investigate the muscle fibre type composition in both muscles. There is accumulating evidence that nonspecific chronic low back pain is associated with lumbar muscle dysfunction. To further elucidate this lumbar paraspinal muscle dysfunction, it is important to understand the structural characteristics of individual muscle fibres of LM and ES. Muscle fibre type composition can be investigated in muscle tissue samples. So far, muscle samples are taken by using invasive procedures that are not well tolerated. The aim of this article was to evaluate the feasibility, accuracy and safety of a percutaneous fine-needle biopsy technique to obtain muscle samples from LM and ES in persons with nonspecific chronic low back pain and to evaluate the feasibility of performing immunofluorescence analysis of myosin heavy chain isoform expression to investigate muscle fibre type composition. Preliminary investigations in cadavers were performed to determine the optimal vertebral level and puncture site to obtain muscle samples of LM and ES through a single skin puncture. In 15 persons with nonspecific chronic low back pain, muscle samples of LM and ES were taken under local anaesthesia with the percutaneous fine-needle biopsy technique, preceded by determination of the puncture site with ultrasonography. Muscle fibre type composition was investigated using immunofluorescence analysis of myosin heavy chain expression. The subjects reported little or no pain and were willing to repeat the procedure. The obtained muscle tissue contained transverse-sectioned muscle fibres in which muscle fibre contractile characteristics of the paraspinal muscles could be evaluated with immunofluorescence analysis of the myosin heavy chains. We can conclude that percutaneous microbiopsy appears to be feasible and accurate, and safe to use to obtain muscle tissue from the paraspinal muscles. The use of ultrasonography to determine the puncture site is necessary to ensure biopsy of the correct muscles and to ensure the safety of the procedure.

Feasibility of high intensity training in nonspecific chronic low back pain: A clinical trial.

BACKGROUND: Although low to moderate intensity exercise therapy is a predominant part of rehabilitation in nonspecific chronic low back pain (NSCLBP), effect sizes are small and optimal exercise modalities/intensities are unclear. Conversely, effects of high intensity training have not yet been investigated in this population. OBJECTIVE: The aim of this study is to investigate the feasibility of high intensity training (HIT) and to explore the magnitude of the effects of a HIT program on exercise capacity and disease related outcome measures compared to conventional therapy for persons with NSCLBP. METHODS: In this non-randomized controlled feasibility study, treatment satisfaction, adherence, disability, pain, physical activity, body composition, exercise capacity and self-reported motivation, were assessed in persons with NSCLBP, before (PRE) and after (POST) 6 weeks (12 sessions, 1.5 hours/session, 2 x/week) of high intensity cardiovascular (100% VO2Max) and high load resistance (80% 1RM) training (HIT, n= 10) and compared to average intensity/load (60% VO2max) conventional physical therapy (CON, n= 10). RESULTS: At PRE, CON and HIT did not differ, except for gender ratio and lean mass. Compared to CON, HIT retained motivation to rehabilitate better (HIT: +3%; CON: -25%) and had higher therapy adherence (+16%) during the study course. No adverse events were noted in both groups. Whereas disability reduced in both groups (HIT: -10.4%; CON: -8.3%), peak workload (+7.0%), time to exhaustion (+9.5%), and activity level (+5.6%) only improved in HIT. CONCLUSIONS: High intensity exercise therapy appears to be a feasible rehabilitation approach in NSCLBP. Outcomes improved following the HIT protocol, warranting the investigation of its effectiveness in future large scale RCT studies.