The two hypotheses to be tested in this study are that:

1. The administration of transcutaneous electrical muscle stimulation (TCEMS) after completion of conventional exercise training in pulmonary rehabilitation (PR) will result in further improvements in exercise tolerance, functional status and symptoms of patients with stable chronic obstructive pulmonary disease (COPD) above those achieved in PR alone.
2. TCEMS can improve exercise tolerance, functional status and symptoms even among COPD patients who fail to make gains in exercise tolerance by participating in conventional PR due to their debilitation and/or marked cardio-respiratory impairment.

Although a substantial body of evidence supports the existence of skeletal muscle dysfunction in COPD and the benefits of PR for these patients, the role of TCEMS as a routine rehabilitative strategy for patients with COPD has yet to be established. The studies proposed in this research will build on the knowledge gained in our previous study of TCEMS by investigating whether and how TCEMS adds to the beneficial effects of PR on exercise capacity and muscle function among outpatients with stable COPD, and by assessing for the first time whether TCEMS improves exercise tolerance and functional status among COPD patients unable to make gains following conventional outpatient PR. Thus, this proposed study may provide a novel strategy in the rehabilitation of patients with chronic lung disease.

The two specific aims of the proposed study are:

1. Determine whether administration of TCEMS after conventional exercise training in PR leads to added gains in muscle strength, exercise capacity, dyspnea and health status, to determine if TCEMS should be considered as an additional routine method in outpatient PR programs.
2. Determine whether patients who are unable to improve exercise tolerance during conventional exercise training in PR can achieve gains in muscle strength, exercise tolerance, dyspnea, and health status following TCEMS used as an alternate rehabilitative strategy.

Inclusion Criteria:

Pulmonary function test criteria consistent with a diagnosis of COPD including forced expiratory volume in one second (FEV1) < 65% of predicted, with FEV1/FVC (forced vital capacity) ratio < 70%, lung hyperinflation based on a residual volume to total lung capacity (RV/TLC) ratio > 120% predicted and reduced diffusing capacity for carbon monoxide (DLCO <70% predicted).

Self-reported exercise limitation despite pharmacologic treatment.

Otherwise medically stable.

Women and minorities will also be recruited. Only persons able to give fully informed consent will be enrolled in the study.

Exclusion Criteria:

Patients will be excluded from study participation if they have a history of uncontrolled cardiovascular disease (including ventricular arrhythmia, myocardial infarction within 1 year, unstable angina, cardiac pacemaker or other implanted electrical device, other uncontrolled arrhythmias, or unstable blood pressure), neuromuscular disease (including stroke), debilitating joint disease or amputations that precludes exercise or have other contraindications to participating in outpatient PR (including unstable bone fracture, syncope of unclear etiology or cancer undergoing active chemotherapy), or are pregnant. Persons with a history of seizure disorder, intracranial clips or skin problems that would prevent safe or proper placement of the electrodes needed for electrical stimulation of the leg muscles will be excluded, based on prior clinical studies of TCEMS in non-COPD populations. Patients will also be excluded from study participation if they have undergone formal PR within 1 year of the date of study inclusion. No patients will be recruited from a "vulnerable patient population", including economically or educationally disadvantaged or mentally disabled persons, children, or prisoners.