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Updated: Aug 24, 2025
Home-Based Prescribed Pulmonary Exercise in Patients with Stable Chronic Obstructive Pulmonary Disease
Published on: August 24, 2019
Isokinetic testing of quadriceps function in COPD: feasibility, responsiveness, and minimal important differences in
Anouk A F Stoffels1, Roy Meys2, Hieronymus W H van Hees3
1Department of Pulmonary Diseases, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Research and Development, Ciro, Horn, the Netherlands; Nutrim School of Nutrition and Translational Research in Metabolism, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands.
Background:
Isokinetic testing of peripheral muscle function is valid and reliable in patients with chronic obstructive pulmonary disease (COPD).
Objective:
To evaluate whether and to what extent isokinetic testing of quadriceps function meets pre-defined test criteria in patients with COPD; to determine the response to pulmonary rehabilitation (PR), and to calculate minimal important differences (MIDs) of isokinetic quadriceps function.
Methods:
Retrospective analysis of 2033 patients with COPD (age: 65±9 years, body mass index: 26±6 kg/m2, FEV1: 49±22% predicted) who followed a comprehensive PR program. Pre and post PR isokinetic quadriceps function was assessed with 30 maximal extension-flexion contractions at an angular speed of 90°/s on a computerized dynamometer. The chosen anchors were 6-min walk test and COPD assessment test.
Results:
Pre PR, 27% of the patients performed the isokinetic test incorrectly. In male and female patients with a correct pre and post PR isokinetic test, peak torque (Δ=10±13 Nm or 9% and Δ=7±9 Nm or 10%, respectively) and total work (Δ=263±270 J or 14% and Δ=198±190 J or 15%, respectively) improved significantly. There was no change in work fatigue index following PR. Using distribution-based calculations, MID estimates for peak torque and total work ranged between 6-7 Nm and 97-135 J in males and between 4-5 Nm and 62-99 J in females.
Conclusions:
Based on the current test criteria, three in four patients with COPD performed the isokinetic quadriceps test correctly during baseline PR assessment. Furthermore, peak torque and total work, but not work fatigue index, were responsive to PR and sex-specific MIDs were established.
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