Peripheral muscle strength and lung function in adults with cystic fibrosis

People with CF (pwCF) have decreased lung function, lean body mass, tensile strength, and exercise tolerance compared to age-matched healthy individuals. We investigated the relationship between peripheral muscle strength, pulmonary function, and inspiratory muscle strength in pwCF.

155 participants (51 % female, 35.2 ± 13.5 years-old; 49 % male, 35.6 ± 11.5 years-old) were evaluated for handgrip strength (HGS), forced vital capacity percent predicted (FVCpp), and forced expiratory volume in 1 s percent predicted (FEV1pp). A subset of participants (n = 86; 52 % female, 37.6 ± 13.2 years-old; 48 % male, 35.6 ± 11.5 years-old) underwent maximal inspiratory pressure (MIP) testing.

Across the entire cohort, peak HGS and FVCpp were significantly correlated (P < 0.05). Multiple regression analyses identified that HGS, body mass index, physical activity, and resistance training were significant independent correlates of FVCpp in females, but not in males. No significant correlation was found between HGS and FEV1pp, but physical activity was correlated with FEV1pp in females (P < 0.05). MIP testing identified a correlation between HGS and inspiratory muscle strength (P < 0.001, r = 0.47), with males demonstrating a more pronounced association than females (P = 0.007, r = 0.41 vs. P = 0.144, r = 0.22, respectively).

In pwCF, HGS was associated with inspiratory muscle strength and FVCpp, underscoring its potential as a feasible adjunctive measure alongside lung function testing. These findings highlight resistance training as a modifiable target warranting further investigation to support both muscular and respiratory outcomes in this population.