Single Limb Resistance Training in Patients With Chronic Obstructive Pulmonary Disease (COPD)

The chronic airflow limitation in chronic obstructive pulmonary disease (COPD) patients resulting in increased dyspnea during physical activity restricts many COPD patients ability to perform exercises in general and whole-body exercises in particular. Single limb training performed as one-legged cycling has been shown effective in patients with COPD. This exercise regime results in less stress on the ventilatory system as training is executed using a simultaneously smaller muscle mass. However, the positive physiological effects of exercise training only occur in the involved muscle(s). To be of benefit for patients daily life, all relevant muscles should be included in exercise training. The aim of the current randomized controlled multicenter trial (RCT) is to determine the effects of high-repetitive single limb exercises (HRSLE) in combination with COPD specific patient education, compared to the COPD specific patient education alone in patients with moderate to very severe (stage II-IV) COPD.

Chronic obstructive pulmonary disease (COPD) is a major cause of chronic morbidity and mortality in the world. It is one of our most common chronic diseases and up to 700.000 people is estimated to suffer from COPD in Sweden. Exercise intolerance is the key disabling factor in COPD, with decreased exercise capacity, leg fatigue and dyspnea among the most frequently reported symptoms.

Different training modalities have been evaluated to uncover the most effective way of training patients with COPD. Traditionally research has used whole-body, or major muscle mass training regimes when investigating the effect of both endurance and resistance in COPD patients. However recent research have demonstrated positive effects using training regimes involving a simultaneous smaller muscle mass compared to traditional exercise. The concept of using this regime is to put less stress on the ventilator system when exercising to minimize the effect of the chronic airflow limitation and to enhance the ability to be able to exercise for this group of patients compared to traditional training using major muscle mass exercise regimes. Although recent research have shown positive effects of single limb training using one-legged cycling, one major limitation is that only a small amount of important muscles for COPD patients are incorporated. Therefore, the aim of this study is to: (i) examine the effect of a single limb exercise regime on local muscle endurance, maximal strength, quality of life, dyspnea, walking capacity, self-efficacy, anxiety and depression, (ii) to examine if the physiological effects differ between man and women and (iii) to investigate if this exercise regime is feasible and safe to use for patients with COPD.

Patients diagnosed with moderate to very severe COPD according to GOLD criteria will be randomly assigned to constitute either an exercise or control group The exercise group will participate in a high-repetitive single limb exercise regime, consisting of upper and lower limb exercises with elastic resistance, compromised of three sessions per week over a period of 8 weeks. The exercise regime will be performed in group at Umeå University Hospital of Northern Sweden, and at Huddinge University Hospital, Sweden supervised by experienced physiotherapists. Both the exercise and control group will receive four sessions of standardized patient education during the 8 week intervention period. After completion of the study, patients in the control group will be offered participation in the single limb exercise regime.

The most important upper and lower extremity muscles for COPD patients are identified and exercises are designed specific to each of these. The exercise regime consists of 8 exercises, 4 upper extremity and 4 lower extremity exercises. Starting position and performance of the exercises are standardized and the resistance individually adjusted and progressed according to rated dyspnea and muscle fatigue.

Before and after the 8 week intervention period the following information will be collected. Effects on maximal strength, muscular endurance, dyspnea, self-efficacy, anxiety and depression. The relationship between changes in health related variables and changes in exercise capacity, sex related differences in training effects, feasibility of the program, strategies to determine adequate starting resistance and provide accurate resistance for each involved movement and the relationship between muscle fatigue and dyspnea in the different exercise tests will also be analyzed.

Eligibility Criteria:
Inclusion Criteria:

1. Adults 40 years and above.
2. Stable (no exacerbations within 4 weeks before start of baseline testing) moderate to very severe COPD, stage II-IV, according to GOLD criteria i.e. Forced expiratory volume in one second (FEV1)/ forced vital capacity (FVC) \< 0.70, FEV1 \< 80% predicted.
3. Ex-smoker.
4. Stable medical treatment (no changes \< 4 weeks before start of baseline testing).
5. Living less than 60 km from training facility.

Exclusion Criteria:

1. Musculoskeletal, rheumatic, cardiac or neurological disorders that might affect the exercise performance in training and tests.
2. Previous lung surgery.
3. Acute exacerbations of COPD that require a change in pharmacological management within four weeks preceding the start of the intervention
4. Long-term oxygen treatment.
5. Participated in organized exercise training, \> 2 times a week, within 6 months before start of intervention.
6. Body mass index (BMI) \< 18 kg/m2.