Validity and reliability of the modified sphygmomanometer test to assess strength of the lower limbs and trunk muscles after stroke.

OBJECTIVES To investigate the criterion-related validity, test-retest and inter-rater reliabilities of the modified sphygmomanometer test (MST) for assessment of the strength of the trunk and lower limb muscles in subjects with chronic stroke, and to verify whether the number of trials affected the results. PATIENTS AND METHODS Fifty-nine subjects with stroke (mean age 57.80 years; standard deviation 13.79 years) were included in the study. Maximum isometric strength was assessed with a hand-held dynamometer and the MST. To investigate whether the number of trials affected the results, one-way analysis of variance was applied. For the criterion-related validity, test-retest and inter-rater reliabilities of the MST, Pearson correlation coefficients, coefficients of determination, and intra-class correlation coefficient (ICC) were calculated. RESULTS Different numbers of trials provided similar values for all assessed muscles (0.003 ≤ F ≤ 0.08; 0.92 ≤ p ≤ 1.00) with adequate validity (0.79 ≤ r ≤ 0.90; p ≤ 0.001), test-retest (0.57 ≤ ICC ≤ 0.98; p ≤ 0.001), and inter-rater reliabilities (0.53 ≤ ICC ≤ 0.97; p ≤ 0.001), except for the inter-rater reliability of the non-paretic ankle plantar flexors. The values obtained with the MST were good predictors of those obtained with the hand-held dynamometer (0.57 ≤ r2 ≤ 0.79). CONCLUSION In general, the MST showed adequate criterion-related validity, test-retest and inter-rater reliabilities for the assessment of strength of the lower limb and trunk muscles in subjects with chronic stroke. For the majority of the assessed muscles, only one trial, after familiarization, provided adequate strength values.