Back pain, physical function, and estimates of aerobic capacity: what are the relationships among methods and measures?

Relationship between subjectively-rated and objectively-tested physical function across six different medical diagnoses

OBJECTIVE

To quantify and compare associations and relationships between self-rated and tested assessments of mainly mobility-related physical function in different diagnoses.

DESIGN

Six longitudinal cohort studies before and after inpatient rehabilitation.

PATIENTS

Patients with whiplash-associated disorder (n = 71), low back pain (n = 121), fibromyalgia (n = 84), lipoedema (n = 27), lymphoedema (n = 78), and post-acute coronary syndrome (n = 64).

METHODS

Physical function was measured with the self-rated Short-Form 36 Physical functioning (SF-36 PF) and with the tested 6-Min Walk Distance (6MWD) and assessed by correlation coefficients. Across the 6 cohorts, the relationship between the 2 scores was compared using the ratio between them.

RESULTS

The correlations between the 2 scores were mostly moderate to strong at baseline (up to r = 0.791), and weak to moderate for the changes to follow-up (up to r = 0.408). The ratios SF-36 PF to 6MWD were 1.143-1.590 at baseline and 0.930-3.310 for the changes, and depended on pain and mental health.

CONCLUSION

Moderate to strong cross-sectional and moderate to weak longitudinal correlations were found between the 6MWD and the SF-36 PF. Pain and mental health should be considered when interpreting physical function. For a comprehensive assessment in clinical practice and research, the combination of self-rated and tested physical function measures is recommended.

Association of Functional Disability and Biopsychosocial Factors in Older Adults With Low Back Pain Who Live in the Amazonas State Brazil: A Cross-Sectional Study

OBJECTIVE

The purpose of this study was to identify social and clinical factors associated with levels of functional disability (FD) in older adults with low back pain (LBP) in the city of Manaus, Amazonas, Brazil.

METHODS

A cross-sectional study of 557 adults with LBP aged ≥60 years was completed. Sociodemographic and clinical features, pain intensity (Numeric Rating Scale), FD (Roland Morris Disability Questionnaire), physical activity (International Physical Activity Questionnaire-short version), body mass index, educational level, health perception, emotional level, and self-reported diseases were evaluated. Statistical analysis was used to verify the association between quantitative variables and a group; Student t test or Mann-Whitney test, and analysis of variance (normality assumption) or Kruskal-Wallis test (non-parametric), P value of less than .05.

RESULTS

There were 81.3% female participants, 54.9% self-reported their race and/or skin color as brown, and 37.8% were sedentary. Pain intensity scores were 6.26 ± 2.19 in female participants and 5.82 ± 1.84 in male participants. Mean FD scores were 11.68 ± 6.08 for female participants and 9.61 ± 5.76 for males participants, although 39.7% of the total group presented with severe disability (score ≥14) and FD was associated with female sex (P = .001), physical activity (P≤ 0.001), body mass index (P≤ .001), emotional level (P < .001), and health perception (P < .001).

CONCLUSION

In this group of older adults with LBP, FD was associated with female sex, level of physical activity, body mass index, emotional level, and health perception. Many factors that were identified with FD are modifiable; therefore, interventions, such as nutrition education and re-conceptualization of self-emotional and health perception, may have potential to help in preventing and reducing FD.

Convergent validity of clinical tests which are hypothesized to be associated with physical functioning in patients with nonspecific chronic low back pain

BACKGROUND

Up until now, assessment of physical functioning in patients with low back pain is mostly completed with the use of patient reported outcome measurements (PROMs). There are however limitations to the use of these measurements such as inaccuracies due to recall bias, social desirability bias and errors in self-observation. A recent review indicated seven clinical tests as having good test retest reliability. These tests can now be further investigated for their validity.

OBJECTIVES

To investigate the convergent validity of seven clinical tests (extensor endurance, flexor endurance, 5 minute walking, 50 foot walking, shuttle walk, sit to stand and the loaded forward reach test) in patients with nonspecific chronic low back pain (CLBP).

METHODS

Patients filled in a series of PROMs and performed all included clinical tests during a specific test moment. Convergent validity was firstly investigated by assessing Pearson correlations between the seven included clinical tests and secondly by assessing the correlations between the predefined PROMs and the clinical tests.

RESULTS

Twenty-five patients were included in this study representing a power of 84%. The best overall evidence for convergent validity could be identified for the extensor endurance, sit to stand and the loaded forward reach test. However, when all study results were combined, evidence for convergent validity was found for all included clinical tests except for the shuttle walk test.

CONCLUSION

The current study was able to provide evidence that multimethod and multidimensional approaches should be used as a more comprehensive assessment of physical function in patients with nonspecific CLBP.

Reliability of physical functioning tests in patients with low back pain: a systematic review

PURPOSE

The aim of this study was to provide a comprehensive overview of physical functioning tests in patients with low back pain (LBP) and to investigate their reliability.

DATA SOURCES

A systematic computerized search was finalized in four different databases on June 24, 2017: PubMed, Web of Science, Embase, and MEDLINE.

STUDY SELECTION

Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed during all stages of this review. Clinical studies that investigate the reliability of physical functioning tests in patients with LBP were eligible. The methodological quality of the included studies was assessed with the use of the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) checklist. To come to final conclusions on the reliability of the identified clinical tests, the current review assessed three factors, namely, outcome assessment, methodological quality, and consistency of description.

DATA SYNTHESIS

A total of 20 studies were found eligible and 38 clinical tests were identified. Good overall test-retest reliability was concluded for the extensor endurance test (intraclass correlation coefficient [ICC]=0.93-0.97), the flexor endurance test (ICC=0.90-0.97), the 5-minute walking test (ICC=0.89-0.99), the 50-ft walking test (ICC=0.76-0.96), the shuttle walk test (ICC=0.92-0.99), the sit-to-stand test (ICC=0.91-0.99), and the loaded forward reach test (ICC=0.74-0.98). For inter-rater reliability, only one test, namely, the Biering-Sörensen test (ICC=0.88-0.99), could be concluded to have an overall good inter-rater reliability. None of the identified clinical tests could be concluded to have a good intrarater reliability.

CONCLUSIONS

Further investigation should focus on a better overall study methodology and the use of identical protocols for the description of clinical tests. The assessment of reliability is only a first step in the recommendation process for the use of clinical tests. In future research, the identified clinical tests in the current review should be further investigated for validity. Only when these clinimetric properties of a clinical test have been thoroughly investigated can a final conclusion regarding the clinical and scientific use of the identified tests be made.

Functional capacity and its associated factors in the elderly with low back pain

OBJECTIVE:

To assess the level of functional capacity in subjects aged 60 years and older, who have lower back pain, and its association with demographic, socioeconomic, work-related, lifestyle-related and disease mentioned variables.

METHODS:

A cross-sectional study was conducted with 246 elderly registered at the Family Health Strategy of Vila São Paulo, Bauru,SP, Brazil, who reported lower back pain and were sampled by a two-stage cluster technique. The subjects were interviewed at home by using a multidimensional instrument (demographic; socioeconomic aspects; life style; work characterization; disease mentioned), and also the IPAQ, the Nordic and the Roland Morris questionnaires. A bivariate and multivariate descriptive logistic regression analysis was carried out.

RESULTS:

The prevalence of lower back pain in men was of 25.1% and in women it was of 35.1%. The mean score in the functional capacity assessment was 10.46 ± 5.62. A fraction of 67.5% of the elderly demonstrated an inappropriate functional capacity. The age group from 70 to 80 years old, the subjects reporting three or more diseases and the sedentary group presented an independent association with inappropriate functional capacity.

CONCLUSION:

The older, sedentary subjects and who reported more than three diseases presented low functional capacity. Level of Evidence III, Cross Sectioning.

Relationship between self-reported disability and functional capacity in patients with whiplash associated disorder

PURPOSE

Patients with chronic Whiplash Associated Disorders (WAD) report symptoms and disability. Neither the relationship between self-reported disability and functional capacity, nor its predictors have been investigated in patients with WAD. This was the purpose of this study.

METHOD

This was a cross-sectional study. Participants were patients with WAD on sick leave. Self-reported disability was assessed with the Neck Disability Index (NDI). Functional capacity was assessed with a six-item neck functional capacity evaluation (FCE). Correlation coefficients were used to express the relationship between NDI (total and items) and FCE. Multivariate linear regression analyses were performed to identify independent predictors of NDI and FCE.

RESULTS

Forty patients were measured, of whom 18 (45 %) were male. Mean age was 33 years, median duration of complaints was 12 months, and 75 % had a pending insurance claim. Correlations between NDI and FCE tests varied from -0.39 to -0.70. Independent predictors of NDI were pain intensity and a pending claim, explaining 43 % of the variance. independent predictors of fce were ndi, gender, and pain intensity, explaining 20-55 % of the variance.

CONCLUSIONS

Self-reported disability and functional capacity are related but different. Both can part be predicted by pain intensity. A pending claim can predict higher self-reported disability. Both constructs are complementary and are recommended to determine disability in patients with WAD comprehensively.

Influence of Mckenzie protocol and two modes of endurance exercises on health-related quality of life of patients with long-term mechanical low-back pain

INTRODUCTION

Long-term Mechanical Low-Back Pain (LMLBP) negatively impacts on patients' physical capacity and quality of life. This study investigated the relationship between Health-Related Quality of Life (HRQoL) and pain intensity, and the influence of static and dynamic back extensors' endurance exercises on HRQoL in Nigerian patients with LMLBP treated with the McKenzie Protocol (MP).

METHODS

A single-blind controlled trial involving 84 patients who received treatment thrice weekly for eight weeks was conducted. Participants were assigned to the MP Group (MPG), MP plus Static Back Endurance Exercise Group (MPSBEEG) or MP plus Dynamic Endurance Exercise Group (MPDBEEG) using permuted randomization. HRQoL and pain was assessed using the Short-Form (SF-36) questionnaire and Quadruple Visual Analogue Scale respectively.

RESULTS

Sixty seven participants aged 51.8 ± 7.35 years completed the study. A total drop-out rate of 20.2% was observed in the study. Within-group comparison across weeks 0-4, 4-8 and 0-8 of the study revealed significant differences in HRQoL scores (p < 0.05). Treatment Effect Scores (TES) across the groups were significantly different (p = 0.001). MPSBEEG and MPDBEEG were comparable in TES on General Health Perception (GHP) at week 4; and GHP and Physical Functioning at week 8 respectively (p > 0.05). However, MPDEEG had significantly higher TES in the other domains of the SF-36 (p = 0.001).

CONCLUSION

HRQoL in patients with LMLBP decreases with pain severity. Each of MP, static and dynamic back extensors endurance exercises significantly improved HRQoL in LMLBP. However, the addition of dynamic back extensors endurance exercise to MP led to greater improvement in HRQoL.

Factors associated with functional capacity test results in patients with non-specific chronic low back pain: a systematic review

INTRODUCTION

Functional capacity tests are standardized instruments to evaluate patients' capacities to execute work-related activities. Functional capacity test results are associated with biopsychosocial factors, making it unclear what is being measured in capacity testing. An overview of these factors was missing. The objective of this review was to investigate the level of evidence for factors that are associated with functional capacity test results in patients with non-specific chronic low back pain.

METHODS

A systematic literature review was performed identifying relevant studies from an electronic journal databases search. Candidate studies employed a cross-sectional or RCT design and were published between 1980 and October 2010. The quality of these studies was determined and level of evidence was reported for factors that were associated with capacity results in at least 3 studies.

RESULTS

Twenty-two studies were included. The level of evidence was reported for lifting low, lifting high, carrying, and static lifting capacity. Lifting low test results were associated with self-reported disability and specific self-efficacy but not with pain duration. There was conflicting evidence for associations of lifting low with pain intensity, fear of movement/(re)injury, depression, gender and age. Lifting high was associated with gender and specific self-efficacy, but not with pain intensity or age. There is conflicting evidence for the association of lifting high with the factors self-reported disability, pain duration and depression. Carrying was associated with self-reported disability and not with pain intensity and there is conflicting evidence for associations with specific self-efficacy, gender and age. Static lifting was associated with fear of movement/(re)injury.

CONCLUSIONS

Much heterogeneity was observed in investigated capacity tests and candidate associated factors. There was some evidence for biological and psychological factors that are or are not associated with capacity results but there is also much conflicting evidence. High level evidence for social factors was absent.

The assessment of function: How is it measured? A clinical perspective

Testing for outcome or performance can take many forms; including multiple iterations of self-reported measures of function (an assessment of the individual's perceived dysfunction) and/or clinical special tests (which are primarily assessments of impairments). Typically absent within these testing mechanisms is whether or not one can perform a specific task associated with function. The paper will operationally define function, discuss the construct of function within the disablement model, will overview the multi-dimensional nature of 'function' as a concept, will examine the current evidence for functional testing methods, and will propose a functional testing continuum. Limitations of functional performance testing will be discussed including recommendations for future research.

The relationship between physical activity and low back pain outcomes: a systematic review of observational studies

Although clinical guidelines advocate exercise and activity in the management of non-specific low back pain (NSLBP), the link between levels of physical activity and outcomes is unclear. This systematic review investigated the relationships between free living activity levels after onset of low back pain (LBP) and measures of pain, and disability in patients with NSLBP. Cohort and cross-sectional studies were located using OVID, CINAHL, Medline, AMED, Embase, Biomed, PubMed-National Library of Medicine, Proquest and Cochrane Databases, and hand searches of reference lists. Studies were included if a statistical relationship was investigated between measures of free living physical activity (PA) in subjects with LBP and LBP outcome measures. Twelve studies (seven cohort and five cross-sectional) were included. One prospective study reported a statistically significant relationship between increased leisure time activity and improved LBP outcomes, and one cross-sectional study found that lower levels of sporting activity were associated with higher levels of pain and disability. All other studies (n = 10) found no relationship between measures of activity levels and either pain or disability. Heterogeneity of study designs, particularly in terms of activity measurement, made comparisons between studies difficult. These data suggest that the activity levels of patients with NSLBP are neither associated with, nor predictive of, disability or pain levels. Validated activity measurement in prospective research is required to better evaluate the relationships between PA and LBP.

Do depression and pain intensity interfere with physical activity in daily life in patients with Chronic Low Back Pain?

Patients with chronic pain may have difficulties estimating their own physical activity level in daily life. Pain-related factors such as depression and pain intensity may affect a patients' ability to estimate their own daily life activity level. This study evaluates whether patients with Chronic Low Back Pain (CLBP) who are more depressed and/or report more pain indeed have a lower objectively assessed daily life activity level or whether they only perceive their activity level as lower. Patients with CLBP were included in a cross-sectional study. During 14days physical activity in daily life was measured, with both an electronic diary and an accelerometer. Multilevel analyses were performed to evaluate whether a higher level of depression and/or pain intensity was associated with a lower objectively assessed activity level or the discrepancy between the self-reported and objectively assessed daily life activity levels. Results, based on 66 patients with CLBP (mean RDQ score 11.8), showed that the objectively assessed daily life activity level is not associated with depression or pain intensity. There was a moderate association between the self-reported and objectively assessed activity levels (beta=0.39, p<0.01). The discrepancy between the two was significantly and negatively related to depression (beta=-0.19, p=0.01), indicating that patients who had higher levels of depression judged their own activity level to be relatively low compared to their objectively assessed activity level. Pain intensity was not associated with the perception of a patient's activity level (beta=0.12, ns).

The usability of a modified Astrand bicycle test to assess the aerobic capacity in patients with musculoskeletal pain and healthy controls

PURPOSE

The aim of this study was to assess the usability of a modified Astrand bicycle test in subjects with musculoskeletal pain disorder (MSPD) and healthy controls.

METHODS

In a random cross-over design, 31 subjects with a MSPD who have been referred to rehabilitation medicine and 33 healthy subjects matched for age, gender, height and body weight, performed an Astrand bicycle test and a modified test with a time interval of 7 days. Drop-out rates, VO2max values (in mL/kg lean body mass (LBM) min(-1)), intraclass correlation coefficients (ICCs) and critical difference (Bland-Altman plots) for both tests within each group of subjects were compared.

RESULTS

The drop-out rate in both tests for the MSPD group was comparable, and mainly caused by pain, fatigue or breathlessness. Compared with the modified version, the Astrand test showed higher VO2max-scores: 4.83 mL/kg LBM min(-1) (9.96%) in the MSPD group and 3.5 mL/kg LBM min(-1) (5.57%) in the healthy group. ICCs were 0.79 and 0.87 and the limits of agreement were 8.5 mL/kg LBM min(-1) (15.9%) and 10.2 mL/kg LBM min(-1) (18.1%), respectively.

CONCLUSION

The usability of the modified test is acceptable, as well as in healthy individuals as subjects suffering from MSPD being referred to rehabilitation medicine. However, a slight under estimation of VO2max with the modified test has to be taken into account.

Does physical activity change predict functional recovery in low back pain? Protocol for a prospective cohort study

BACKGROUND

Activity advice and prescription are commonly used in the management of low back pain (LBP). Although there is evidence for advising patients with LBP to remain active, facilitating both recovery and return to work, to date no research has assessed whether objective measurements of free living physical activity (PA) can predict outcome, recovery and course of LBP.

METHODS

An observational longitudinal study will investigate PA levels in a cohort of community-dwelling working age adults with acute and sub-acute LBP. Each participant's PA level, functional status, mood, fear avoidance behaviours, and levels of pain, psychological distress and occupational activity will be measured on three occasions during for 1 week periods at baseline, 3 months, and 1 year. Physical activity levels will be measured by self report, RT3 triaxial accelerometer, and activity recall questionnaires. The primary outcome measure of functional recovery will be the Roland Morris Disability Questionnaire (RMDQ). Free living PA levels and changes in functional status will be quantified in order to look at predictive relationships between levels and changes in free living PA and functional recovery in a LBP population.

DISCUSSION

This research will investigate levels and changes in activity levels of an acute LBP cohort and the predictive relationship to LBP recovery. The results will assess whether occupational, psychological and behavioural factors affect the relationship between free living PA and LBP recovery. Results from this research will help to determine the strength of evidence supporting international guidelines that recommend restoration of normal activity in managing LBP.

TRIAL REGISTRATION

[Clinical Trial Registration Number, ACTRN12609000282280].

Self-reported assessment of disability and performance-based assessment of disability are influenced by different patient characteristics in acute low back pain

For an individual, the functional consequences of an episode of low back pain is a key measure of their clinical status. Self-reported disability measures are commonly used to capture this component of the back pain experience. In non-acute low back pain there is some uncertainty of the validity of this approach. It appears that self-reported assessment of disability and direct measurements of functional status are only moderately related. In this cross-sectional study, we investigated this relationship in a sample of 94 acute low back pain patients. Both self-reported disability and a performance-based assessment of disability were assessed, along with extensive profiling of patient characteristics. Scale consistency of the performance-based assessment was investigated using Cronbach's alpha, the relationship between self-reported and performance-based assessment of disability was investigated using Pearson's correlation. The relationship between clinical profile and each of the disability measures were examined using Pearson's correlations and multivariate linear regression. Our results demonstrate that the battery of tests used are internally reliable (Cronbach's alpha = 0.86). We found only moderate correlations between the two disability measures (r = 0.471, p < 0.001). Self-reported disability was significantly correlated with symptom distribution, medication use, physical well-being, pain intensity, depression, somatic distress and anxiety. The only significant correlations with the performance-based measure were symptom distribution, physical well-being and pain intensity. In the multivariate analyses no psychological measure made a significant unique contribution to the prediction of the performance-based measure, whereas depression made a unique contribution to the prediction of the self-reported measure. Our results suggest that self-reported and performance-based assessments of disability are influenced by different patient characteristics. In particular, it appears self-reported measures of disability are more influenced by the patient's psychological status than performance-based measures of disability.

Reliability and validity of the Japanese-language version of the physical performance test (PPT) battery in chronic pain patients

PURPOSE

To prepare a Japanese-language version of the Physical Performance Test (PPT) Battery and assess its reliability and validity.

METHOD

Activity limitations by pain were evaluated by means of the Japanese-language version of the PPT Battery in 82 patients with chronic pain in the limbs and trunk. Two self-report questionnaires, one related to sensory evaluation of pain, and the other related to affective evaluation of pain, and the Functional Independence Measure (FIM), which evaluates activities of daily living, were simultaneously administered to the subjects.

RESULTS

The results for reliability showed that the ICC values for inter-rater reliability and intra-rater reliability were 0.91 or more for every item. The results for validity showed significant associations between the scores for all of the items on the Japanese-language version of the PPT Battery and the total scores on the FIM (p < 0.01). Significant associations were found between 5 of the 8 items on the Japanese-language version of the PPT Battery and affective state due to the pain.

CONCLUSIONS

The Japanese-language version of the PPT Battery was shown to possess adequate reliability and validity as a scale for evaluating the activity limitations of patients with chronic limb or trunk pain. The results also suggested that it might be possible to improve the activity limitations of patients with chronic pain by improving their affective state in response to the pain.

Physical capacity tasks in chronic low back pain: What is the contributing role of cardiovascular capacity, pain and psychological factors?

PURPOSE

To explore the association of personal and body functions with physical capacity tasks used in the evaluation of chronic low back pain (CLBP) treatment.

METHOD

Cross-sectional study in which 221 patients with non-specific CLBP participated. Physical capacity was assessed by six capacity tasks, and several personal and body functions were assessed by questionnaires (age, gender, pain intensity, duration of pain, radiating pain to leg, fear of injury/movement, depression, pain catastrophizing and internal control of pain). Cardiovascular capacity was measured by a modified Astrand submaximal bicycle test. The association of these hypothetically influential personal and body function factors with capacity tasks was examined with multiple linear regression analyses.

RESULTS

The total explained variance was low to moderate (9 - 19%), except for stair climbing for which the variance just reached 30%. Many putative factors did not contribute significantly to the level of outcome of several different tasks.

CONCLUSIONS

Cardiovascular capacity, pain intensity, fear of injury/movement, cognitions, and depression had statistically significant but clinically minor effects on several, but not all capacity tasks. Radiating pain, age and duration of complaints had no significant influence at all. Due to anthropometric differences men outperformed women on most tasks. Apparently the influence of many personal, physical but especially psychological factors on the selected capacity tasks is not high at all. This might indicate that these tasks are more objectively measuring physical capacity than expected.

General and specific self-efficacy reports of patients with chronic low back pain: are they related to performances in a functional capacity evaluation?

INTRODUCTION

The objective of this study was to analyze the relationship of general and specific self-efficacy (SE) beliefs with functional capacity evaluation (FCE) performances in patients with chronic non-specific low back pain (CLBP), while controlling for influence of gender, age, and self-reported pain intensity, self-esteem, disability, psychosocial distress and health status.

METHODS

Included were 92 patients with CLBP referred to an outpatient university based multidisciplinary pain rehabilitation program in The Netherlands. All patients underwent an FCE. General SE was measured with the ALCOS questionnaire prior to the FCE, specific SE was measured with a self-constructed standardized question during the FCE. Paired samples t-tests were used to tests differences between predicted and actual performances. Pearson and Spearman rank correlation coefficients were used to express the strength of the relationships between SE and performances. Multivariate analyses were used to test the influence of control variables on the relationships between SE (general or specific) and performances.

RESULTS

Performances were consistently higher than patients' self-predictions. Differences between predictions and performances were significant in male lifting low, male carrying, and female carrying. With exception of the association between specific SE and lifting in males (r = 0.55, P < 0.05), all other correlations between general and specific SE and FCE performances were non-significant. Multivariable regression analyses showed that the relative contribution of SE measures over gender was little or none.

CONCLUSIONS

The contribution of specific SE to the prediction of FCE performances is moderate in one instance, and insignificant in most instances (both specific and general SE). Because of the consistency of the differences between prediction (specific SE) and performances, and depending on the level of accuracy needed, future research may deliberate the use of predicted material handling capacities at group level and correct for a systematic underprediction.

Comparison of three different approaches in the treatment of chronic low back pain

Our aim is to investigate the effects of three therapeutic approaches in the chronic low back pain on pain, spinal mobility, disability, psychological state, and aerobic capacity. Sixty patients with chronic low back pain were randomized to three groups: group 1, aerobic exercise + home exercise; group 2, physical therapy (hot pack, ultrasound, TENS) + home exercise; group 3, home exercise only. Spinal mobility, pain severity, disability, and psychological disturbance of the patients were assessed before and after the treatment and at 1-month follow-up. Aerobic capacities of the patients were measured before and after treatment. All of the groups showed similar decrease in pain after the treatment and at 1-month follow-up, and there was no significant difference between the groups. In group 2, a significant decrease in Beck Depression Inventory scores was observed with treatment. At 1-month follow-up, group 1 and 2 showed significant decreases in General Health Assessment Questionnaire scores. In group 2, there was also a significant improvement in Roland Morris Disability scores. There were similar improvements in exercise test duration and the MET levels in all the three groups. All of the three therapeutic approaches were found to be effective in diminishing pain and thus increasing aerobic capacity in patients with chronic low back pain. On the other hand, physical therapy + home exercise was found to be more effective regarding disability and psychological disturbance.

The impact of aerobic fitness on functioning in chronic back pain

Despite lack of convincing evidence that reduced aerobic fitness is associated with chronic back pain (CBP), exercise programs are regarded as being effective for persons with non-specific CBP. It is unsure whether gain in aerobic fitness following intervention is associated with functioning improvement in persons with CBP. The objective of this prospective cohort study was to study the impact of aerobic fitness on functioning in persons with CBP, at baseline and following 3-week intensive interdisciplinary intervention. This study included persons who had passed 8 weeks of sick-listing because of back pain (n = 94) and were referred to a 3-week intensive biopsychosocial rehabilitation program. Aerobic fitness was assessed with a sub-maximal bicycle test at baseline, at admission to and discharge from the rehabilitation program, and at 6 months follow-up. Contextual factors, body function, activity and participation were evaluated before and after intervention. In addition, working ability was recorded at 3-years follow-up. At baseline aerobic fitness was reduced in most subjects, but improved significantly following intervention. Baseline measurements and intervention effects did not differ among the diagnostic sub-groups. Neither contextual factors nor functioning at baseline were associated with aerobic fitness. Increase in aerobic fitness was not associated with improvements in functioning and contextual factors and work-return following intervention either. From this study we conclude that improvement of aerobic fitness seems of limited value as goal of treatment outcome for patients with CBP.

Relationships Between Performance-Based Tests and Patients’ Ratings of Activity Limitations, Self-Efficacy, and Pain in Fibromyalgia

OBJECTIVE

To investigate the relationship between performance-based tests, ratings of activity limitations, self-efficacy, and pain in fibromyalgia.

DESIGN

Descriptive.

SETTING

University hospital.

PARTICIPANTS

Sixty-nine women with fibromyalgia (mean age, 45+/-7.8y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The patients completed 4 performance-based tests focusing on muscle power function and 3 unloaded arm movements. The patients rated their activity limitations by means of the subscales of physical function (PF) and pain on the Fibromyalgia Impact Questionnaire (FIQ), the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), and the Arthritis Self-Efficacy Scale (ASES). Spearman correlation coefficient (rho) and multivariate regression analysis were conducted.

RESULTS

The highest correlations were found between the 6-minute walk test (6MWT) (rho range, -.48 to .68) and the activity limitations and between hand grip strength (rho range, -.34 to .57) and the activity limitations. The regression analysis indicated that hand grip strength explained 25% of the variation in the SF-36 PF scale. The 6MWT plus endurance of the shoulder muscles explained 24% of the variation in the FIQ PF scale and the 6MWT plus active abduction of the shoulder explained 48% of the variation in the ASES function scale. Correlations between the performance-based tests and the activity limitations tended to be higher than those between performance and pain.

CONCLUSIONS

The majority of the performance-based tests and the patients' subjective ratings of activity limitations showed significant relationships. The 6MWT and hand grip strength, reflecting activity limitations in the SF-36, FIQ, and ASES, are recommended for use in clinical research and in the clinical examination when planning treatment for patients with fibromyalgia.

Physical functioning: self-report and performance measures are related but distinct

STUDY DESIGN

Cross-sectional study of 63 patients with chronic low back pain (CLBP).

OBJECTIVES

To determine the relationship between the SF-36 physical functioning (PF) scale and physical performance on a modified symptom limited treadmill test, and to determine the effect of disability status and SF-36 mental health (MH) scores on self-reported physical functioning and on physical performance.

SUMMARY OF BACKGROUND DATA

Patients with CLBP report low levels of physical functioning. Because self-report measures are influenced by psychosocial factors, such as disability and low MH, a common recommendation is to supplement self-report with objective or physical performance testing. Little information exists regarding whether performance testing is also influenced by disability and low MH.

MATERIALS AND METHODS

Patients completed the SF-36 and performed a maximal, symptom-limited, modified treadmill test. Total walking time and heart rate on the treadmill were registered. The effects of disability and low MH on self-report and performance testing were calculated by unpaired Student's t-testing and effect size estimation.

RESULTS

A strong relationship between the PF scale of the SF-36 and treadmill walking time was found, but there was little evidence of overlap between these physical functioning domains. Both disability status and low MH had a much larger effect on self-report measures than on physical performance.

CONCLUSIONS

Self-report measurements and performance-based assessments provide information about distinct, although related, domains of physical functioning. Disability and low MH are associated with lower SF-36 PF scores. Our results confirm that self-report measures require supplementation with objective performance testing to provide optimal assessment for patients with CLBP.