Effect of combined strength and endurance training in adults with asthma: a randomized controlled trial

Objective: Pulmonary rehabilitation programs, including exercise training, have an established role in the treatment of chronic respiratory diseases but are not routinely used in asthma. Most studies of individuals with asthma have focused on endurance training, and there is therefore limited data available on strength training. The aim of this study was to evaluate the effects that adding strength training to a program of endurance training and education has on the quality of life of such individuals. Methods: In this single-center, parallel-group randomized controlled trial, adults with moderate-to-severe asthma admitted for in-hospital pulmonary rehabilitation between June of 2021 and October of 2022 were randomized to either a study group (SG) or a control group (CG). The SG received strength training alongside endurance training and education, whereas the CG received the same endurance training and education, along with sham mobility exercise training instead of strength training. The primary outcome was the change in the Asthma Quality of Life Questionnaire (AQLQ) score from hospital admission to discharge. Results: A total of 61 participants were randomized, with 31 being assigned to the SG and 30 being assigned to the CG. At discharge, the AQLQ score showed significant improvement in both groups (p < 0.001 for the SG and p = 0.02 for the CG), albeit without a significant difference between the groups (p > 0.99). In contrast, peripheral muscle strength improved significantly from admission to discharge only in the SG, with a significant difference between the groups in terms of quadriceps strength (p = 0.03). Conclusions: Adding strength training to endurance training and education does not seem to result in further improvement in the quality of life of individuals with moderate-to-severe asthma.