all patients received the Control Group treatment added to global exercise treatment. The program included 15 minutes of deep breathing exercises and 20-30 minutes of limb exercises. The exercises included global active range of motion (ROM) exercises and muscle strengthening like upper and lower limbs flexion-extension do single-leg stance, and sit to stand exercises. The number of repetitions was adapted to the subject's response taken into account the perceived dyspnea and fatigue during the exercise performance.

all patients received the Control Group treatment plus neuromuscular stimulation therapy (SEFAR Rehab X2, DJO France S.A.S., France) on quadriceps accompanied by lower limb exercises. The intervention was performed following the protocol described by Valenza et al (2017).

Valenza MC, Torres-Sánchez I, López-López L, Cabrera-Martos I, Ortiz-Rubio A, Valenza-Demet G. Effects of home-based neuromuscular electrical stimulation in severe chronic obstructive pulmonary disease patients: a randomized controlled clinical trial. Eur J Phys Rehabil Med. 2018 Jun;54(3):323-332. doi: 10.23736/S1973-9087.17.04745-1. Epub 2017 Nov 16. PubMed PMID: 29144103.

Patients received standard medical and pharmacological care that consisted in systemic steroids, inhaled bronchodilators, oxygen, and a regimen of oral prednisone or its equivalent in doses of 40 to 60 mg per day for the duration of therapy as well as anti-biotic therapy.

The program included 15 minutes of deep breathing exercises and 20-30 minutes of limb exercises. The exercises included global active range of motion (ROM) exercises and muscle strengthening like upper and lower limbs flexion-extension do single-leg stance, and sit to stand exercises

Quadriceps strength was assessed with a portable hand-held dynamometer (Lafayette Manual Muscle Testing System, model 01163, Lafayette, IN, USA). The test was performed with the patient seated with his/her knees and hips flexed at 90°. Resistance was applied to the anterior tibia during 5 seconds of maximal muscle contraction. The test was repeated alternatively 3 times on the leg, allowing participants to rest between measurements. The highest value in Newton was selected for the analysis.

Quadriceps strength was assessed with a portable hand-held dynamometer (Lafayette Manual Muscle Testing System, model 01163, Lafayette, IN, USA). The test was performed with the patient seated with his/her knees and hips flexed at 90°. Resistance was applied to the anterior tibia during 5 seconds of maximal muscle contraction. The test was repeated alternatively 3 times on the leg, allowing participants to rest between measurements. The highest value in Newton was selected for the analysis.

Balance was evaluated by the one-leg standing balance test (OLS), that measured the time that the patient balances on one leg as long as possible. The patient choose a leg to stand on (whichever he felt more comfortable with), flex the opposite knee allowing the foot to clear the floor, and balance on one leg. Higher values mean better balance.

Balance was evaluated by the one-leg standing balance test (OLS), that measured the time that the patient balances on one leg as long as possible. The patient choose a leg to stand on (whichever he felt more comfortable with), flex the opposite knee allowing the foot to clear the floor, and balance on one leg. Higher values mean better balance.