Different Properties of the Erector Spinae and Multifidus Muscles on Physical Performance in Patients With Chronic Obstructive Pulmonary Disease.

Abstract

Background: Muscle atrophy in the dorsal muscle group (DMG) is associated with physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD). However, no studies have separately evaluated the erector spinae muscle (ESM) and the multifidus muscle (MM) within the DMG, leaving the distinct impact of each muscle on PA unclear.

Purpose: This study evaluated the differences in muscle characteristics between ESM and MM in stable patients with COPD.

Patients and methods: In Study 1, we evaluated the relationship between the cross-sectional area of ESM (ESM_CSA) and MM (MM_CSA) on chest computed tomography and PA parameters. In Study 2, as a pilot study, we analyzed the muscle fatigue characteristics of ESM and MM using a trunk holding test and electromyographic (EMG) power spectrum analysis to evaluate the median frequency (MF) slope. We then evaluated the differences in the MF slopes of both muscles in patients with COPD compared with healthy subjects.

Results: Of 77 patients with COPD, the MM_CSA was positively associated with the duration of PA at ≥3.0 metabolic equivalents (METs) (r=0.279, p=0.014), whereas the ESM_CSA was negatively associated with the duration of behavior at 1.0-1.5 METs (r=-0.429, p<0.001). The MF slopes of the MM were significantly lower in COPD patients (n=7) than in healthy subjects (n=28) (p<0.01), indicating greater fatigue, with no significant differences in MF slopes for ESM or trunk extension holding time.

Conclusion: These results indicate that the functional characteristics of the ESM and MM differ in COPD patients. MM was mainly associated with moderate-to-vigorous PA and involved greater fatigue in COPD patients compared to healthy subjects, while the ESM was mainly associated with sedentary behavior.