Evidence on resistance-training programs for cystic fibrosis (CF) is limited and the possible benefits of the addition of neuromuscular electrical stimulation (NMES) are unknown. This study aimed to evaluate the effects of a supervised resistance-training program, associated or not with NMES, on muscle strength, aerobic fitness, lung function and quality of life in children with CF presenting mild-to-moderate pulmonary impairment.

This is a randomized controlled trial including CF patients aged between 6 and 17years. Subjects were randomly allocated to control (CON); exercise (EX); or exercise and NMES (EX + NMES) groups, and evaluated at baseline and at the end of an 8-week individualized exercise-program (3 days/week, 60min/session). NMES was applied in the quadriceps and the interscapular region, simultaneously to the exercises. CON group followed the CF team recommendations. The main outcome measures were lung function, cardiorespiratory fitness, functional capacity, quality of life and muscle strength.

Twenty-seven patients, aged 12.6 ± 3.0 years, were analyzed. No significant interactions were found for cardiorespiratory fitness. Functional capacity presented significant differences, indicating a better performance in both EX and EX + NMES. No significant changes between groups were seen for quality of life and lung function. As for muscle strength, EX and EX + NMES presented large effect sizes and significant differences, compared to CON, for quadriceps (p = 0.004, η²_p = 0.401), pectoral (p = 0.001, η²_p = 0.487), dorsal (p = 0.009, η²_p = 0.333) and handgrip (p = 0.028, η²_p = 0.278).

A resistance exercise-training program led to improvements in muscle strength and functional capacity in CF patients with mild-to-moderate pulmonary impairment. The addition of NMES to the training program resulted in no extra favorable effects.