Construct validity and reliability of the 2-Minute Step Test (2MST) in individuals with low back pain.

BACKGROUND: Functional tests are important clinical tools, since they are non-invasive methods, with simple applicability, and low cost. However, there are few tests adapted for individuals with chronic low back pain. Thus, our objective was to evaluate the test-retest and inter-rater reliability of the 2-Minute Step Test in individuals with chronic low back pain and to correlate the test score with measures of pain and physical activity. METHODS: We included patients aged between 18 and 45 years, of both sexes, and with low back pain. The interval between the test and retest was 7 days. We analyzed the data via intra-class correlation coefficient (ICC), confidence interval at 95%, standard error of measurement, and minimum detectable change for reliability. We used the Spearman's correlation coefficient to verify the correlation between 2-Minute Step Test and measures of pain and physical activity (Numerical Pain Scale, Roland-Morris Disability Questionnaire, Pain-Related Catastrophizing Thoughts Scale, Tampa Scale of Kinesiophobia, and Baecke Habitual Physical Activity Questionnaire). RESULTS: Sample is composed of 37 individuals, most of them female, with overweight and low back pain > 60 months. 2-Minute Step Test showed excellent test-retest (ICC = 0.903) and inter-rater (ICC = 0.925) reliability. Sport domain of the Baecke showed a significant correlation with the 2-Minute Step Test (rho = 0.444). CONCLUSION: 2-Minute Step Test is a reliable measure to measure the functional capacity of patients with chronic low back pain considering different times and examiners, as well as being positively correlated with sports practice.

Association between adherence to a home exercise program and central sensitization, pain intensity, and functionality in individuals with knee osteoarthritis.

OBJECTIVE: To analyze the association between adherence to a home exercise program and central sensitization, pain intensity, and functionality in individuals with knee osteoarthritis (KOA). METHODS: A cross-sectional study was conducted involving 57 individuals with KOA. Evaluations were performed using the Exercise Adherence Rating Scale (EARS), the numerical rating scale (NRPS), the International Knee Documentation Committee (IKDC), The Central Sensitization Inventory (CSI), and the 30 sec sit and stand test (30SSST). Histograms were created to determine the normality of the data. The Kolmogorov-Smirnov test was used to determine the normality of the data. Thus, Pearson's (r) and determination (R2) correlation coefficients were calculated to determine the strength of associations between variables. RESULTS: No significant association was found between adherence behavior or reasons for adherence and central sensitization symptoms, the intensity of pain on rest and movement, knee disability symptoms, and functionality. CONCLUSION: No significant association was identified between adherence to a home exercise program and central sensitization, pain intensity, and functionality in individuals with KOA.

15-item Roland-Morris Disability Questionnaire (RMDQ-15): structural and criterion validity on patients with chronic low back pain.

BACKGROUND: The Roland-Morris Disability Questionnaire (RMDQ) is one of the most used instruments to measure self-reported disability in patients with low back pain, however, the uncertainty on which version to use may lead to inadequate disability measurement and consequently, improper management of patients with chronic low back pain. OBJECTIVE: To propose a short version of the RMDQ, compare it with the other short versions presented by the specialized literature, and identify the best internal structure of the RMDQ for the Brazilian population. METHODS: This is a cross-sectional study in which we used confirmatory factor analysis to identify the best structure of the RMDQ. We assessed 545 participants, most of which were women, aged ≥ 30 years old, single, with mean low back pain intensity ~ 5 points, and mean pain chronicity ~ 72 months. We used lavaan and semPlot packages, with implementation of a tetrachoric matrix and the robust diagonally weighted least squares extraction method. We also used fit indices chi-square/degree of freedom, comparative fit index, Tucker-Lewis index, root mean square error of approximation, and standardized root mean squared residual. For the comparison between models, we considered the structure with the lowest values of the Akaike information criterion and Bayesian information criterion. In addition, we assessed criterion validity via Spearman's correlation coefficient to correlate the long and short versions. In this study, the 15-item structure was created through the use of modification indices to identify redundant items (9 items were excluded). RESULTS: RMDQ structure with one domain and 15 items and the structure with two domains and 16 items showed all fit indices with adequate values, but the one-dimensional version showed the lowest Akaike information criterion and Bayesian information criterion values. Regarding criterion validity, correlation between the RMDQ with 24 items and 15 items is adequate (rho = 0.954, p < 0.001). CONCLUSION: The RMDQ-15 is a short version of the RMDQ instrument with the most adequate internal structure and satisfactorily correlated with the long version of the instrument.