Assessment of muscular strength with the modified sphygmomanometer test: what is the best method and source of outcome values?

BACKGROUND: Tests that are usually employed for the clinical assessment of muscular strength have notable disadvantages. The Modified Sphygmomanometer Test (MST) is a promising method because it is low-cost and provides objective measures. OBJECTIVES: To investigate the most adequate method and sources of outcome values for the assessment of strength with the MST. METHOD: Methodological study with 40 healthy adults (22.98±2.26 years), who did not practice physical activity regularly. The strength of the flexors and extensors of the elbow and knee, the handgrip of the dominant side and anterior trunk flexors were randomly assessed with portable dynamometers and the MST (bag and cuff adaptations, and sphygmomanometer without adaptation) by a single examiner. An independent examiner read and recorded the values. The sources of the investigated outcome values were the first trial and the means of two and three trials. One-way ANOVAs and Pearson Correlation Coefficients were used for the analyses (α=0.05). RESULTS: For the MST methods applied to assess all muscular groups, similar values were found for all sources of outcome values (0.01<F<0.26; 0.77<p<1.00) with significant and positive correlations between the measures obtained with the dynamometers (0.51<r<0.94; p<0.003). CONCLUSIONS: All MST methods showed adequate results for the assessment of strength in healthy individuals, and after familiarization, only one trial was sufficient to provide reliable measures. The sphygmomanometer without adaptation is not time consuming, compared to the other adaptations, and showed the capability of measuring higher values of strength. The bag method was easily trained to be used and stabilized.