Introduction:
Expiratory muscle weakness and dyspnoea are common in patients suffering from chronic obstructive pulmonary disease (COPD) and negatively affect their exercise capacity. We aimed to highlight the combined effect of Russian current and a threshold positive expiratory pressure (PEP) device on expiratory muscle strength, dyspnoea, and functional capacity in patients with COPD.

Methods:
A total of 60 males with COPD were involved in this controlled randomised trial (age ranged 55–65 years and median body mass index [BMI] was 28.68–25.96) and randomly assigned into two equal groups (30 for each), to receive combined Russian current and PEP device (study group) or PEP device only (control group), for three sessions per week over a ten-week period. Maximum expiratory pressure (MEP), dyspnoea (modified Borg scale – MBS), and functional capacity (6-minute walk test) were assessed before and after the intervention.

Results:
There was statistically significant improvement in all measured variables (MEP, MBS, and 6-minute walk test) in either the study group or the control group according to Wilcoxon’s sign rank test (all were p < 0.001 and p < 0.01, respectively), however, the study group showed a more significant improvement compared to the control group according to the Mann–Whitney U-test (p < 0.001).

Conclusions:
Combined Russian current and PEP device had a superior beneficial effect on improving dyspnoea and functional capacity by boosting the expiratory muscle strength in COPD patients, which could be implemented in their management, although further studies are needed to evaluate its maintenance effect.