Handgrip strength and its relation to isokinetic dynamometry in COPD

Abstract

Introduction: Muscle dysfunction is one of the major changes found in chronic obstructive pulmonary disease (COPD) and associated with loss of functionality, morbidity and mortality. Objective: correlate two strength assessment methods: manual dynamometry for handgrip strength and isokinetic dynamometry for quadriceps strength in patients with COPD, and assess the body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE), quality of life and muscle strength. Method: twenty-five patients with moderate to very severe COPD were evaluated by pulmonary function parameters, anthropometric variables, functional capacity, via the six-minute walk test, dyspnea, applying the modified Medical Research Council (mMRC) scale, BODE, quality of life, using the Saint George's Respiratory Questionnaire (SGRQ), handgrip strength with manual dynamometer and quadriceps force using an isokinetic dynamometer. Muscle strength was assessed with a manual portable dynamometer and isokinetic dynamometer. For statistical analysis, ANOVA with Bonferroni’s post-test, the chi-squared test and Pearson's correlation coefficient were used. Results: There was a strong correlation between the strength measurements and the two instruments (torque and quadriceps extension power with right handgrip strength: r = 0.74; p <0.001). The patients classified as very severe exhibited worse performance in the strength tests when compared to the moderate group, albeit with no statistically significant difference. Conclusion: In muscle strength measurements, a strong correlation was detected between the isokinetic dynamometer for quadriceps and the manual dynamometer for handgrip strength. These findings indicate that, in clinical practice, the manual dynamometer for handgrip strength could be used to assess peripheral muscle strength in patients with COPD.