Resistance exercise applications during acute exacerbations of Chronic Obstructive Pulmonary Disease (COPD) are employed to enhance functional capacity and prevent muscle atrophy by increasing muscle strength.

Owing to the limited cardiorespiratory reserve of COPD patients, single-limb exercises are better tolerated compared to traditional bilateral exercises. A study conducted by Vogiatzis et al. (2009) indicated that single-leg exercises require lower ventilation and result in more efficient oxygen consumption than bilateral exercises. This physiological advantage may be effective in reducing muscle weakness by increasing exercise endurance in COPD patients with restricted respiratory capacity.

The present study aims to demonstrate that single-limb resistance exercise is an effective rehabilitation method for increasing functional exercise capacity in patients during COPD exacerbations compared to a control group. Furthermore, the therapeutic effects of single-limb resistance exercises on dyspnea perception, fatigue, anxiety, and depression will be established. The study will also show that these exercises are both feasible and safe within rehabilitation protocols during the exacerbation period.

Pathophysiology and Rehabilitation in Acute Exacerbation of COPD An acute exacerbation of Chronic Obstructive Pulmonary Disease (COPD) represents an acute process that accelerates disease progression and exerts systemic effects. This period is characterized by a sudden worsening of primary symptoms, such as dyspnea, increased sputum volume, and heightened sputum viscosity. Exacerbations lead to increased hospitalization rates, diminished quality of life, and elevated mortality among COPD patients. According to the GOLD 2024 report, a COPD exacerbation is defined as an event characterized by increased dyspnea, cough, and sputum that develops in less than 14 days and necessitates a change in treatment. These episodes are generally attributed to increased airway infection, environmental pollution, or other inflammatory triggers.

During these periods, respiratory functions decline acutely, leading to impaired oxygenation and physiological stress. Research indicates a significant decrease in skeletal muscle function during exacerbations, with muscle weakness becoming a prominent clinical feature. This acute weakness develops due to various factors, including systemic inflammation, nutritional deficiencies, and the use of corticosteroids. Observations show a reduction in myoblast determination proteins and insulin-like growth factor-I levels in skeletal muscle during the exacerbation process; this suggests that physical inactivity is a critical factor in acute muscle dysfunction.

Most patients face conditions requiring inactivity, such as bed rest, during an exacerbation. Inactivity causes a rapid decline in muscle strength, particularly in older individuals; one study demonstrated that 10 days of bed rest resulted in a 15% reduction in quadriceps strength. Under stressful conditions, this effect becomes even more pronounced, and medications such as corticosteroids can exacerbate the detrimental effects of inactivity. Limitation of physical activity during this period both accelerates skeletal muscle loss and adversely affects the long-term mobilization capabilities of patients.

Treatment during a COPD exacerbation aims to alleviate symptoms and improve quality of life. Management typically involves bronchodilators (β2-agonists and anticholinergics), inhaled corticosteroids, and antibiotics. Furthermore, systemic corticosteroids can rapidly improve symptoms by suppressing inflammation. Approaches such as pulmonary rehabilitation, exercise, and breathing techniques can reduce dyspnea by increasing functional capacity . Non-invasive positive pressure ventilation (NIPPV) is utilized for patients experiencing severe respiratory distress. To prevent infections, influenza and pneumococcal vaccinations are recommended, while smoking cessation and avoiding air pollution also reduce the risk of exacerbation.

Exercise performed during a COPD exacerbation helps patients maintain physical capacity and accelerates the recovery process. However, exercises during this period must be meticulously planned, as acute exacerbations lead to impaired respiratory function and increased systemic inflammation. Exercise interventions are typically initiated at low intensity to preserve cardiorespiratory function, support muscle strength, and ensure general mobility.

Low-intensity cardiorespiratory endurance exercises, such as walking or stationary cycling, are recommended during the exacerbation period. These exercises improve oxygenation in skeletal muscles. A study by Vaes et al. (2017) stated that low-intensity cardio exercises initiated during a COPD exacerbation are effective in preserving functional capacity. During an exacerbation, weakness may be observed particularly in the lower extremities, such as the quadriceps. Lower extremity exercises initiated at low resistance levels help patients maintain muscle function and reduce skeletal muscle loss. The study by Greening et al. showed that low-intensity resistance exercises during the exacerbation period are safe and effective for increasing muscle strength .

In COPD, single-limb exercises are implemented to increase tolerance to physical activity and preserve muscle strength, especially during the exacerbation period. These exercises aim to work muscle groups in isolation by focusing on one limb, thereby minimizing energy consumption and reducing the risk of exercise intolerance. During single-limb exercises, muscles operate with lower oxygen consumption because the other limb remains in a resting position; this is better tolerated by COPD patients experiencing severe dyspnea or fatigue The primary objective of our study is to determine the effectiveness of single-limb resistance exercises in patients with COPD during the exacerbation phase. This research aims to evaluate the potential of this exercise modality to improve the physiological and psychological status of patients during an acute episode.

H0: Single-limb exercise training applied to COPD patients during exacerbation does not change functional exercise capacity compared to the control group.

H1: Single-limb exercise training applied to COPD patients during exacerbation changes functional exercise capacity compared to the control group.

Hypothesis 2:

H02: Single-limb exercise training applied to COPD patients during exacerbation does not change the perception of dyspnea and fatigue compared to the control group.

H2: Single-limb exercise training applied to COPD patients during exacerbation changes the perception of dyspnea and fatigue compared to the control group.

Hypothesis 3:

H03: Single-limb exercise training applied to COPD patients during exacerbation does not change peripheral muscle strength compared to the control group.

H3: Single-limb exercise training applied to COPD patients during exacerbation changes peripheral muscle strength compared to the control group.

Inclusion Criteria:

Hospital admission due to an acute COPD exacerbation.

Not currently enrolled in an active pulmonary rehabilitation program.

Absence of any additional neurological disorders.

Exclusion Criteria:

Heart failure classified as New York Heart Association (NYHA) Class III or IV. Unstable mental status (indicated by a Mini-Mental State Examination (MMSE) score of 24).

History of major surgery within the last three months. Presence of malignancies.