Low Load, High-repetitive Elastic Band Resistance Training in COPD

Meters walked on the 6- minute walk test. The walking course will be 30 meters in length and the patients will be instructed in accordance to standardized guidelines to walk as far as possible in 6 minutes. One practice test will be performed to minimize risk of learning effect. The highest walking distance of the two 6-min walks will be chosen as baseline value.

Endurance time (seconds) on the Unsupported Upper Limb Exercise test (UULEX) will be used to measure unsupported endurance capacity in the upper extremity. Participants will hold a plastic bar (0.2 kg), at shoulder width and will be asked to raise it from hip to the UULEX eight level chart for one minute at each level with a cadence of 30 movements per minute. If a patient reaches the highest level, the plastic bar will be replaced by a heavier one every minute. There are five different weights of the bar (0.2, 0.5, 1, 1.5, 2 Kg) and the patient will continue on the highest level until symptom limitation.

Isokinetic limb muscle function during one-arm shoulder flexion, one-leg knee extension and two-leg knee extension will be assessed. The subjects are informed to flex their arm or extend their leg(s) 25 consecutive times using maximal effort at each repetition during the concentric phase and to rest during the eccentric phase of the movement. Two different aspects of isokinetic muscle function will be measured. Peak torque from the highest contraction will be used for maximal strength and the total work generated from all contractions will be used for limb muscle endurance. The tests will be performed at an angular velocity of 60°• s-1,

Respiratory response during all elastic band exercises (1: one-arm shoulder flexion, biceps flexion, chest press and latissimus row 2: two-arm shoulder flexion, biceps flexion, chest press and latissimus row 3: one-leg knee extension, plantar flexion and leg curl 4: two-leg knee extension, plantar flexion and leg curl) will be determined using a portable gas analysis system (Oxycon Mobile, Viasys Healthcare, Jaeger, Germany. Minute ventilation (VE) oxygen uptake (VO2), carbon dioxide excretion (VCO2,), heart rate (HR), respiratory exchange ratio (RER) and pulsed oxygen saturation (SpO2) will be collected

Arterial blood pressures and cardiac output will be non-invasively measured by a finger photoplethysmography device (BMEYE, Nexfin HD, Academic Medical Center, Amsterdam, The Netherlands) during all elastic band exercises detailed above.

Changes of deoxyhemoglobin/myoglobin concentrations will be non-invasively measured by near-infrared spectroscopy of vastus lateralis muscle. Obtained during all elastic band exercises detailed above

Magnitude of dyspnea after each exercise and test will be measured by the Borg CR 10 scale

Magnitude of limb muscle fatigue after each exercise and test will be measured by the Borg CR 10 scale

Directly before and after all elastic band exercises (1: one-arm shoulder flexion, 2: two-arm shoulder flexion, 3: one-leg knee extension, 4: two-leg knee extension) generated force of both MVIC and TW will be measured by an isometric force gauge while participants will be in a standardized positioning. The occurrence of quadriceps (knee extension) or deltoid (shoulder flexion) fatigue induced by the exercise regimens will be quantified by measuring the fall in both MVIC and TW 15 after the elastic band resistance exercises.