Health coaching intervention with or without the support of an exercise buddy to increase physical activity of people with chronic low back pain compared to usual care: a feasibility and pilot randomised controlled trial.

BACKGROUND: Exercise buddies (people to exercise together with) might support people with low back pain (LBP) to become active. However, involving buddies in randomised controlled trials (RCT) might challenge recruitment, data collection and follow-up. OBJECTIVES: To explore the feasibility of the intervention, recruitment and data collection approaches and potential effects of a health coaching intervention (focused on physical activity) with or without exercise buddies' support on physical activity of people with chronic LBP versus usual discharge care. DESIGN: Feasibility and pilot RCT. METHODS: Adults (n = 30) discharged from LBP treatment were randomised to the Buddy-Assisted (health coaching intervention with exercise buddy's support), Individual-Only (health coaching only), or usual care groups. Data were collected at baseline, three and six months. The feasibility of trial's procedures was assessed through recruitment rate (acceptable if >70%), data completion rate (acceptable if ≤ 20% missing data), and follow-up rate (successful if ≥ 85%). The intervention's acceptability was assessed via feedback questionnaires. Preliminary effects on physical activity and other outcomes were also explored. RESULTS: Recruitment and baseline data completion were acceptable. However, data collection and follow-up rates post-randomisation were not. 85% of the Buddy-Assisted Group believed the buddies helped them to increase physical activity and would recommend the intervention. 70% of the Individual-Only and Control groups believed exercise buddies would help them to become further active. CONCLUSION: The data collection and follow-up approaches were not successful and need amending before a large-scale RCT. Nonetheless, the buddy-assisted intervention was well-accepted. A future RCT will focus on differences in clinical outcomes. TRIAL REGISTRATION: The study was registered at the Australian New Zealand Clinical Trial Registry (ACTRN12620001118998).

Temporal stability in the prevalence and pattern of co-occurring musculoskeletal pain among people with persistent low back pain: population-based data from the Norwegian HUNT Study, 1995 to 2019.

ABSTRACT: People with persistent low back pain (LBP) often report co-occurring persistent musculoskeletal (MSK) pain in other body regions that may influence prognosis as well as treatment approaches and outcomes. This study describes the prevalence and patterns of co-occurring persistent MSK pain among people with persistent LBP based on consecutive cross-sectional studies over 3 decades in the population-based HUNT Study, Norway. The analyses comprised 15,375 participants in HUNT2 (1995-1997), 10,024 in HUNT3 (2006-2008), and 10,647 in HUNT4 (2017-2019) who reported persistent LBP. Overall, ∼90% of participants in each of the HUNT surveys with persistent LBP reported persistent co-occurring MSK pain in other body sites. The age-standardized prevalence of the most common co-occurring MSK pain sites was consistent across the 3 surveys: 64% to 65% report co-occurring neck pain, 62% to 67% report shoulder pain, and 53% to 57% report hip or thigh pain. Using latent class analysis (LCA), we identified 4 distinct patterns of persistent LBP phenotypes that were consistent across the 3 surveys: (1) "LBP only," (2) "LBP with neck or shoulder pain," (3) "LBP with lower extremity or wrist or hand pain," and (4) "LBP with multisite pain," with conditional item response probabilities of 34% to 36%, 30% to 34%, 13% to 17%, and 16% to 20%, respectively. In conclusion, 9 of 10 adults in this Norwegian population with persistent LBP report co-occurring persistent MSK pain, most commonly in the neck, shoulders, and hips or thighs. We identified 4 LCA-derived LBP phenotypes of distinct MSK pain site patterns. In the population, both the prevalence and pattern of co-occurring MSK pain and the distinct phenotypic MSK pain patterns seem stable over decades.

The selfBACK artificial intelligence-based smartphone app can improve low back pain outcome even in patients with high levels of depression or stress.

BACKGROUND: selfBACK provides individually tailored self-management support for low back pain (LBP) via an artificial intelligence-based smartphone app. We explore whether those with depressive/stress symptoms can benefit from this technology. METHODS: Secondary analysis of the selfBACK randomized controlled trial (n = 461). Participants with LBP were randomized to usual care (n = 229), or usual care plus selfBACK (n = 232). PRIMARY OUTCOME: LBP-related disability (Roland-Morris Disability Questionnaire, RMDQ) over 9 months. SECONDARY OUTCOMES: global perceived effect (GPE)/pain self-efficacy (PSEQ)/satisfaction/app engagement. Baseline depressive symptoms were measured using the patient health questionnaire (PHQ-8) and stress with the perceived stress scale (PSS). Outcomes stratified by baseline PHQ-8/PSS scores to assess associations across the whole cohort, and intervention versus control groups. RESULTS: Participants with higher levels of depressive/stress symptoms reported more baseline LBP-related disability (RMDQ 3.1; 1.6 points higher in most vs least depressed/stressed groups respectively); lower self-efficacy (PSEQ 8.1; 4.6 points lower in most vs least depressive/stressed groups respectively). LBP-related disability improved over time; relative risk of improvement in those with greatest depressive/stress symptoms versus nil symptom comparators at 9 months: 0.8 (95% CI: 0.6 to 1.0) and 0.8 (95% CI: 0.7 to 1.0) respectively. No evidence that different baseline levels of depressive/perceived stress symptoms are associated with different RMDQ/GPE/PSEQ outcomes. Whilst participants with higher PHQ-8/PSS were less likely to be satisfied or engage with the app, there was no consistent association among PHQ-8/PSS level, the intervention and outcomes. CONCLUSIONS: The selfBACK app can improve outcomes even in those with high levels of depressive/stress symptoms and could be recommended for patients with LBP. SIGNIFICANCE: We have demonstrated that an app supporting the self-management of LBP is helpful, even in those with higher levels of baseline depression and stress symptoms. selfBACK offers an opportunity to support people with LBP and provides clinicians with an additional tool for their patients, even those with depression or high levels of stress. This highlights the potential for digital health interventions for chronic pain.

Distribution and prevalence of musculoskeletal pain co-occurring with persistent low back pain: a systematic review.

BACKGROUND: Co-occurring musculoskeletal pain is common among people with persistent low back pain (LBP) and associated with more negative consequences than LBP alone. The distribution and prevalence of musculoskeletal pain co-occurring with persistent LBP has not been systematically described, which hence was the aim of this review. METHODS: Literature searches were performed in MEDLINE, Embase, CINAHL and Scopus. We considered observational studies from clinical settings or based on cohorts of the general or working populations involving adults 18 years or older with persistent LBP (≥4 wks) and co-occurring musculoskeletal pain for eligibility. Study selection, data extraction and risk of bias assessment were carried out by independent reviewers. Results are presented according to study population, distribution and location(s) of co-occurring pain. RESULTS: Nineteen studies out of 5744 unique records met the inclusion criteria. Studies were from high-income countries in Europe, USA and Japan. A total of 34,492 people with persistent LBP were included in our evidence synthesis. Methods for assessing and categorizing co-occurring pain varied considerably between studies, but based on the available data from observational studies, we identified three main categories of co-occurring pain - these were axial pain (18 to 58%), extremity pain (6 to 50%), and multi-site musculoskeletal pain (10 to 89%). Persistent LBP with co-occurring pain was reported more often by females than males, and co-occurring pain was reported more often in patients with more disability. CONCLUSIONS: People with persistent LBP often report co-occurring neck pain, extremity pain or multi-site pain. Assessment of co-occurring pain alongside persistent LBP vary considerable between studies and there is a need for harmonisation of measurement methods to advance our understanding of how pain in different body regions occur alongside persistent LBP. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42017068807 .

Periodized resistance training for persistent non-specific low back pain: a mixed methods feasibility study.

BACKGROUND: We investigated the feasibility of a 16-week supervised heavy resistance training program with weekly undulating periodization for individuals with persistent non-specific low-back pain (LBP). METHODS: Twenty-five adults with persistent non-specific LBP participated in this mixed methods feasibility study. Participants trained a whole-body program consisting of squat, bench press, deadlift and pendlay row two times per week for 16 weeks. We assessed pain intensity, pain-related disability, pain self-efficacy and one-repetition maximum strength at baseline, 8 weeks and 16 weeks. Three focus group interviews were conducted at the end of the program. Linear mixed models were used to assess changes in outcomes, and the qualitative data was assessed using systematic text condensation. RESULTS: We observed clinically meaningful reductions in pain intensity after 8 and 16 weeks of training. The mean difference on the numeric pain rating scale (0-10) in the last 2 weeks from baseline to 8 weeks was 2.6 (95% CI: 1.8-3.6) and from baseline to 16 weeks 3.4 (95% CI: 2.5-4.4). In addition, there were improvements in pain-related disability (3.9, 95% CI: 2.3-5.5), pain self-efficacy (7.7, 95% CI: 5.4-10.1) and muscle strength. In the focus group interviews, participants talked about challenges regarding technique, the importance of supervision and the advantages of periodizing the training. Perceived benefits were improved pain, daily functioning, energy level and sleep, and changes in views on physical activity. CONCLUSION: Periodized resistance training with weekly undulating periodization is a feasible training method for this group of individuals with persistent non-specific LBP. A randomized clinical trial should assess the efficacy of such an intervention. TRIAL REGISTRATION: clinicaltrials.gov / Identifier - NCT04284982, Registered on February 24th 2020.

Family History Influences the Effectiveness of Home Exercise in Older People With Chronic Low Back Pain: A Secondary Analysis of a Randomized Controlled Trial.

OBJECTIVE: To investigate whether a family history of low back pain (LBP) influences patient outcomes and treatment effects following home exercises in older people with chronic LBP. DESIGN: Secondary analysis of a randomized controlled trial. SETTING: Local community. PARTICIPANTS: People older than 55 years with chronic LBP (N=60). INTERVENTIONS: Participants in the intervention group completed video game exercises for 60 minutes 3 times per week for 8 weeks. Participants in the control group were instructed to maintain their usual levels of activity and care seeking behaviors. MAIN OUTCOMES MEASURES: Participants indicated whether any of their immediate family members had a history of "any" LBP or "activity-limiting" LBP at baseline. We collected self-reported measures of pain, function, pain self-efficacy, care seeking, physical activity, disability, fear of movement and/or reinjury, and falls efficacy at baseline, 8 weeks, 3 months, and 6 months. We performed regression analyses to determine whether a family history of LBP predicted patient outcomes and moderated the effects of home exercise. RESULTS: Participants with a family history of any LBP were less likely to be highly active than those without a family history (odds ratio, 0.08; 95% CI, 0.01-0.42; P=.003). Home-based video game exercises led to improvements in function in those without a family history of activity-limiting LBP (ß=1.78; 95% CI, 0.56-3.00; P=.006) but not in those with a family history (ß=-0.17; 95% CI, -2.56 to 2.21; P=.880) (interaction P=.049). A family history of LBP did not influence the remaining patient outcomes or treatment effects. CONCLUSIONS: A family history of LBP appears to negatively influence physical activity levels in older people with chronic LBP. Further, home-based video game exercises appear to be beneficial for older people with chronic LBP that do not have a family history of LBP.

Association between objectively measured physical behaviour and neck- and/or low back pain: A systematic review.

BACKGROUND AND OBJECTIVE: Clinical guidelines recommend physical activity to manage neck pain (NP) and low back pain (LBP). However, studies used to support these guidelines are based on self-reports of physical behaviour, which are prone to bias and misclassification. This systematic review aimed to investigate associations between objectively measured physical behaviour and the risk or prognosis of NP and/or LBP. DATABASES AND DATA TREATMENT: Literature searches were performed in MEDLINE, Embase and Scopus from their inception until 18 January 2019. We considered prospective cohort studies for eligibility. Article selection, data extraction and critical appraisal were carried out by independent reviewers. Results were stratified on activity/sedentariness. RESULTS: Ten articles out of 897 unique records identified met the inclusion criteria, of which eight studied working populations with mainly blue-collar workers. The overall results indicate that increased sitting time at work reduces the risk of NP and LBP while increased physical activity during work and/or leisure increases the risk of these conditions among blue-collar workers; however, associations were weak. Physical activity was not associated with prognosis of LBP (no studies investigated prognosis of NP). Most of the included articles have methodological shortcomings. CONCLUSIONS: This review indicates that, among blue-collar workers, increased sitting at work may protect against NP and LBP while increased physical activity during work and/or leisure may increase this risk. There was no evidence supporting physical activity as a prognostic factor for LBP. Findings should be interpreted with caution due to the weak associations and few available studies with methodological shortcomings. SIGNIFICANCE: Based on prospective cohort studies with objectively measured physical behaviour, this review questions the common notion that increased physical activity is associated with reduced risk or better prognosis of NP and/or LBP. We found that, among blue-collar workers, increased sitting time at work reduces the risk of NP and LBP, whereas physical activity somewhat increases the risk. Despite methodological shortcomings, there was consistency in the direction of the results, although high-quality articles reported the weakest associations. Systematic review registration: PROSPERO CRD42018100765.

Comparison of physical behavior estimates from three different thigh-worn accelerometers brands: a proof-of-concept for the Prospective Physical Activity, Sitting, and Sleep consortium (ProPASS).

BACKGROUND: Pooling data from thigh-worn accelerometers across multiple studies has great potential to advance evidence on the health benefits of physical activity. This requires harmonization of information on body postures, physical activity types, volumes and time patterns across different brands of devices. The aim of this study is to compare the physical behavior estimates provided by three different brands of thigh-worn accelerometers. METHODS: Twenty participants volunteered for a 7-day free-living measurement. Three accelerometers - ActiGraph GT3X+, Axivity AX3 and ActivPAL Micro4 - were randomly placed in a vertical line on the midsection of the right thigh. Raw data from each accelerometer was processed and classified into 8 physical activities and postures using the Acti4 software. Absolute differences between estimates and the respective coefficient of variation (CV) were calculated. RESULTS: We observed very minor differences between physical behavior estimates from three different accelerometer brands. When averaged over 24 h (1,440 min), the absolute difference (CV) between accelerometers were: 1.2 mins (0.001) for lying/sitting, 3.4 mins (0.02) for standing, 3.5 mins (0.06) for moving, 1.9 mins (0.03) for walking, 0.1 mins (0.19) for running, 1.2 mins (0.19) for stair climbing, 1.9 mins (0.07) for cycling. Moreover, there was an average absolute difference of 282 steps (0.03) per 24 h. CONCLUSIONS: Physical behaviors were classified with negligible difference between the accelerometer brands. These results support harmonization of data from different thigh-worn accelerometers across multiple cohorts when analyzed in an identical manner.

Muscle Activity in Upper-Body Single-Joint Resistance Exercises with Elastic Resistance Bands vs. Free Weights.

Elastic resistance bands require little space, are light and portable, but their efficacy has not yet been established for several resistance exercises. The main objective of this study was to compare the muscle activation levels induced by elastic resistance bands versus conventional resistance training equipment (dumbbells) in the upper-body resistance exercises flyes and reverse flyes. The level of muscle activation was measured with surface electromyography in 29 men and women in a cross-over design where resistance loadings with elastic resistance bands and dumbbells were matched using 10-repetition maximum loadings. Elastic resistance bands induced slightly lower muscle activity in the muscles most people aim to activate during flyes and reverse flies, namely pectoralis major and deltoideus posterior, respectively. However, elastic resistance bands increased the muscle activation level substantially in perceived ancillary muscles, that is deltoideus anterior in flyes, and deltoideus medius and trapezius descendens in reverse flyes, possibly due to elastic bands being a more unstable resistance modality. Overall, the results show that elastic resistance bands can be considered a feasible alternative to dumbbells in flyes and reverse flyes.

Do physical activity and body mass index modify the association between chronic musculoskeletal pain and insomnia? Longitudinal data from the HUNT study, Norway.

We investigated the prospective association between chronic musculoskeletal pain and risk of insomnia, and if leisure-time physical activity and body mass index modify this association. The study comprised historical data on 11 909 women and 9938 men in the Norwegian HUNT study without sleep problems at baseline in 1995-97 and followed-up for insomnia in 2006-08. Poisson regression was used to estimate adjusted risk ratios (RRs) with 95% confidence intervals (CIs). Compared to pain-free participants, any chronic pain was associated with a RR of insomnia of 2.27 (95% CI: 1.93, 2.66) in women and 1.58 (95% CI: 1.28, 1.95) in men, whereas reporting ≥5 chronic pain sites gave RRs of 3.20 (95% CI: 2.60, 3.95) and 2.40 (95% CI: 1.76, 3.27), respectively. Analysis of joint effects showed that: (i) compared to pain-free physically active people, RRs in people with ≥5 chronic pain sites were 3.77 (95% CI: 2.42-5.85) if they were inactive and 2.76 (95% CI: 2.29, 3.31) if they were active; and (ii) compared to pain-free people with normal weight, RRs in people with ≥5 chronic pain sites were 3.52 (95% CI: 2.81, 4.40) if they were obese and 2.93 (95% CI: 2.24, 3.84) if they had normal weight. In conclusion, chronic musculoskeletal pain increases the risk of insomnia, particularly among those who report several pain sites. Although there was no clear evidence of modifying effects, our results suggest that a healthy active lifestyle reduces the risk of insomnia in people with chronic musculoskeletal pain.

Prevalence and pattern of co-occurring musculoskeletal pain and its association with back-related disability among people with persistent low back pain: protocol for a systematic review and meta-analysis.

BACKGROUND: Individuals with persistent low back pain commonly have a broad range of other health concerns including co-occurring musculoskeletal pain, which significantly affect their quality of life, symptom severity, and treatment outcomes. The purpose of this review is to get a better understanding of prevalence and patterns of co-occurring musculoskeletal pain complaints in those with persistent low back pain and its potential association with age, sex, and back-related disability as it might affect prognosis and management. METHODS: This systematic review protocol has been designed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols. We will perform a comprehensive search, with no date limit, in the following bibliographic databases: MEDLINE and Embase (via Ovid), CINAHL, and Scopus for citation tracking, based on the following domains: back pain, co-occurring musculoskeletal pain, combined with a focus group that emphasizes study design. Appropriate papers will be screened against the eligibility criteria by three reviewers independently, data extracted by two independent author pairs and disagreement resolved by consensus meetings or other reviewers if required. Assessment of methodological quality and risk of bias will be conducted using a modified version of the Risk of Bias Tool for Prevalence Studies developed by Hoy and colleagues. The overall risk of bias will be determined for each included study based on the raters' consensus of the responses to the items in this tool. In case of sufficiently homogenous studies, meta-analysis will be performed. DISCUSSION: Given the lack of standard terms used to define co-occurring musculoskeletal pain, the search strategy will include the broader term "back pain," different terms for the "other co-occurring pain," and specific study designs combined with several exclusion terms. The results of this proposed review will identify the prevalence and patterns of co-occurring musculoskeletal pain among those with persistent low back pain, which is likely to inform clinical management, research, and policy in management of musculoskeletal disorders. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42017068807.

Digital Support Interventions for the Self-Management of Low Back Pain: A Systematic Review.

BACKGROUND: Low back pain (LBP) is a common cause of disability and is ranked as the most burdensome health condition globally. Self-management, including components on increased knowledge, monitoring of symptoms, and physical activity, are consistently recommended in clinical guidelines as cost-effective strategies for LBP management and there is increasing interest in the potential role of digital health. OBJECTIVE: The study aimed to synthesize and critically appraise published evidence concerning the use of interactive digital interventions to support self-management of LBP. The following specific questions were examined: (1) What are the key components of digital self-management interventions for LBP, including theoretical underpinnings? (2) What outcome measures have been used in randomized trials of digital self-management interventions in LBP and what effect, if any, did the intervention have on these? and (3) What specific characteristics or components, if any, of interventions appear to be associated with beneficial outcomes? METHODS: Bibliographic databases searched from 2000 to March 2016 included Medline, Embase, CINAHL, PsycINFO, Cochrane Library, DoPHER and TRoPHI, Social Science Citation Index, and Science Citation Index. Reference and citation searching was also undertaken. Search strategy combined the following concepts: (1) back pain, (2) digital intervention, and (3) self-management. Only randomized controlled trial (RCT) protocols or completed RCTs involving adults with LBP published in peer-reviewed journals were included. Two reviewers independently screened titles and abstracts, full-text articles, extracted data, and assessed risk of bias using Cochrane risk of bias tool. An independent third reviewer adjudicated on disagreements. Data were synthesized narratively. RESULTS: Of the total 7014 references identified, 11 were included, describing 9 studies: 6 completed RCTs and 3 protocols for future RCTs. The completed RCTs included a total of 2706 participants (range of 114-1343 participants per study) and varied considerably in the nature and delivery of the interventions, the duration/definition of LBP, the outcomes measured, and the effectiveness of the interventions. Participants were generally white, middle aged, and in 5 of 6 RCT reports, the majority were female and most reported educational level as time at college or higher. Only one study reported between-group differences in favor of the digital intervention. There was considerable variation in the extent of reporting the characteristics, components, and theories underpinning each intervention. None of the studies showed evidence of harm. CONCLUSIONS: The literature is extremely heterogeneous, making it difficult to understand what might work best, for whom, and in what circumstances. Participants were predominantly female, white, well educated, and middle aged, and thus the wider applicability of digital self-management interventions remains uncertain. No information on cost-effectiveness was reported. The evidence base for interactive digital interventions to support patient self-management of LBP remains weak.

Hours lying down per day and mortality from all-causes and cardiovascular disease: the HUNT Study, Norway.

Time spent sitting has been positively associated with mortality in several studies, whereas time lying down per day has not been extensively studied. The authors prospectively examined the association between hours lying down per day and risk of death from all-causes and from cardiovascular disease among 39,175 persons aged 20-79 years in the population-based HUNT Study in Norway. Adjusted hazard ratios (HRs) with 95 % confidence intervals (CIs) were obtained from Cox regression, using people lying down for 7 h per day as reference. During a median follow-up of 12.3 years a total of 2,659 persons died (851 from cardiovascular disease). People lying 11-18 h per day had a HR of 1.60 (95 % CI 1.29, 1.98) for death from all causes and a HR of 1.91 (95 % CI 1.35, 2.71) for cardiovascular death. Analyses stratified by leisure time physical activity showed a positive association with cardiovascular mortality also among physically active people, with HRs of 1.38 (95 % CI 0.97, 1.96) and 1.84 (95 % CI 1.07, 3.16) among people lying down 10 and 11-18 h per day, respectively. In this large prospective study, excessive hours lying down per day were associated with increased all-cause and cardiovascular mortality, even among physically active persons.

Sleep problems and risk of fibromyalgia: longitudinal data on an adult female population in Norway.

OBJECTIVE: Sleep problems are common among patients with fibromyalgia (FM). However, it is not known whether poor sleep is a contributing factor in FM or a consequence of the illness. The aim of the current study was to prospectively investigate the association between self-reported sleep problems and risk of FM among adult women. METHODS: We longitudinally studied 12,350 women who did not have FM, musculoskeletal pain, or physical impairments at baseline (1984-1986). A generalized linear model was used to calculate the adjusted relative risk (RR) of FM at followup in 1995-1997. RESULTS: Incident FM was reported by 327 women at followup. A dose-dependent association was found between sleep problems and risk of FM (P for trend<0.001), with an adjusted RR of 3.43 (95% confidence interval [95% CI] 2.26-5.19) among women who reported having sleep problems often or always, compared to women who never experienced sleep problems. Age-stratified analysis showed that women age≥45 years who reported having sleep problems often or always had an adjusted RR of 5.41 (95% CI 2.65-11.05), whereas the corresponding RR for women ages 20-44 years who reported having sleep problems often or always was 2.98 (95% CI 1.76-5.05). CONCLUSION: These prospective data indicate a strong dose-dependent association between sleep problems and risk of FM. The association is somewhat, although not significantly, stronger in middle-aged and older women than in younger women.

Physical exercise, body mass index, and risk of chronic pain in the low back and neck/shoulders: longitudinal data from the Nord-Trondelag Health Study.

Chronic musculoskeletal pain constitutes a large socioeconomic challenge, and preventive measures with documented effects are warranted. The authors' aim in this study was to prospectively investigate the association between physical exercise, body mass index (BMI), and risk of chronic pain in the low back and neck/shoulders. The study comprised data on approximately 30,000 women and men in the Nord-Trøndelag Health Study (Norway) who reported no pain or physical impairment at baseline in 1984-1986. Occurrence of chronic musculoskeletal pain was assessed at follow-up in 1995-1997. A generalized linear model was used to calculate adjusted risk ratios. For both females and males, hours of physical exercise per week were linearly and inversely associated with risk of chronic pain in the low back (women: P-trend = 0.02; men: P-trend < 0.001) and neck/shoulders (women: P-trend = 0.002; men: P-trend < 0.001). Obese women and men had an approximately 20% increased risk of chronic pain in both the low back and the neck/shoulders. Exercising for 1 or more hours per week compensated, to some extent, for the adverse effect of high BMI on risk of chronic pain. The authors conclude that physical inactivity and high BMI are associated with an increased risk of chronic pain in the low back and neck/shoulders in the general adult population.

The effect of delayed onset of muscle soreness on habitual trapezius activity.

The aim of the study was to investigate the effect of acute trapezius pain, induced by delayed onset of muscle soreness (DOMS), on habitual trapezius activity. Long-term (5 h) surface electromyographic (sEMG) activity was recorded bilaterally from the clavicular, descending, transverse, and ascending trapezius on two consecutive weekdays in eleven female subjects (mean age 22 years, range 20-24 years). Body and arm posture were recorded by inclinometers. Immediately after the first long-term recording, the subjects performed eccentric depression exercise of the left shoulder to induce DOMS. From day 1 to day 2, pressure pain threshold (PPT) decreased and pain scores on visual analog scale (VAS) increased for the left upper trapezius (P<.004 for all comparisons). Habitual sEMG activity (median sEMG level, µV) of the clavicular and descending part of the exercised left trapezius increased from first to second long-term recording during periods with seated posture (P<.05 for both comparisons). In contrast, trapezius sEMG activity remained unchanged for all other trapezius parts and postures. This study indicates that acute trapezius pain induces elevated habitual trapezius activity during periods with low biomechanical loading of the shoulder/neck muscles with the elevated sEMG activity being restricted to the painful part of the muscle. In contrast to the pain-adaption model, the current study indicates a relation between acute muscle pain and elevated low-level muscle activity; however, it remains unknown if development of chronic muscle pain can be preceded by an initial stage with elevated muscle activity.

Location and sequence of muscle onset in deep abdominal muscles measured by different modes of ultrasound imaging.

Various modes of ultrasound (US) imaging have been introduced as an alternative to electromyography for determining muscle onset. The purpose of this study was to compare the agreement between US motion-mode (US(m-mode)) and US strain rate (US(SR)) derived from tissue velocity imaging in determining latency time, location and sequence of muscle onset in abdominal muscles using the same data set (contractions). Twenty-four subjects performed four rapid arm flexions in response to a light signal while US recordings were made from the abdominal muscles on the contralateral side. The examined muscles were transversus abdominis (TrA), superficial and deep obliquus internus abdominis (OI(deep) and OI(sup)), and obliquus externus abdominis (OE). The results showed that the two methods detected the first muscle onset on average within 0.1 ms (95% CI; +/-1.4 ms) of each other. US(SR) detected the second muscle onset on average 27 ms after US(m-mode). While US(SR) and US(m-mode) can be used interchangeably to detect the first muscle onset, the location of both first onset and subsequent muscle onsets can be reliably detected by US(SR) only. Furthermore, this study indicates that OI may be functionally subdivided into a superficial and deep region, with onset in OI(deep) occurring on average 53 ms before OI(sup). First onset was detected more frequently in OI than in TrA (65% versus 25% of detected onsets, 10% were equal).

Association between physical exercise, body mass index, and risk of fibromyalgia: longitudinal data from the Norwegian Nord-Trøndelag Health Study.

OBJECTIVE: To examine the association between leisure time physical exercise, body mass index (BMI), and risk of fibromyalgia (FM). METHODS: A longitudinal study with baseline assessment of physical exercise (frequency, duration, and intensity) and BMI was used to explore the risk of having FM at 11-year followup in a large, unselected female population (n = 15,990) without FM or physical impairments at baseline. RESULTS: At followup, 380 cases of incident FM were reported. A weak dose-response association was found between level of physical exercise and risk of FM (for trend, P = 0.13) where women who reported the highest exercise level had a relative risk (RR) of 0.77 (95% confidence interval [95% CI] 0.55-1.07). BMI was an independent risk factor for FM (for trend, P < 0.001), and overweight or obese women (BMI > or =25.0 kg/m(2)) had a 60-70% higher risk compared with women with normal weight (BMI 18.5-24.9 kg/m(2)). Overweight or obese women who exercised > or =1 hour per week had an RR of 1.72 (95% CI 1.07-2.76) compared with normal-weight women with a similar activity level, whereas the risk was >2-fold higher for overweight or obese women who were either inactive (RR 2.09, 95% CI 1.36-3.21) or exercised <1 hour per week (RR 2.19, 95% CI 1.39-3.46). CONCLUSION: Being overweight or obese was associated with an increased risk of FM, especially among women who also reported low levels of physical exercise. Community-based measures aimed at reducing the incidence of FM should emphasize the importance of regular exercise and the maintenance of normal body weight.