Abstract
BACKGROUND: Skeletal muscle dysfunction is an important systemic comorbidity in patients with Chronic Obstructive Pulmonary Disease (COPD). Its etiology is often multifactorial and can be linked to many factors, such as hypercapnia and/or hypoxia, nutritional depletion, use of corticosteroids, oxidative stress and deconditioning. High-intensity exercise training (including strength training) has clearly contributed to improvement in muscle function in these patients. However, the Minimal Important Difference (MID) of quadriceps femoris muscle strength after training is unknown. AIM: To determine the MID of quadriceps femoris muscle strength after a high-intensity exercise training program in patients with COPD. METHODS: Twelve patients (9 women, 66+7 years; BMI 27+5Kg.m-2; FEV1 40+18%pred) taking part in a 6-month high-intensity endurance+strength training program (3x/week) were assessed pre and post-intervention regarding their lung function and quadriceps femoris strength (1 Repetition Maximum and peak force measured by a dynamometer [MicroFet 2®, Hoggan Health, United States of America]). In order to calculate anchor-based estimates of MID, a global rating of change score (Likert Scale) was used; whereas to calculate the distribution-based estimates the Effect Size was used. RESULTS: Mean (95% CI) change in quadriceps femoris strength was 32 (-8 to 72) N.m for patients who reported improvement in the Likert Scale. The Effect Size calculation identified a MID of 33 N.m. CONCLUSION: These preliminary results indicate a MID around 33 N.m for quadriceps femoris strength improvement after exercise training in patients with COPD.
- © 2014 ERS