Author(s): NUEVO-NUEVO, I., PANTOJA-ARÉVALO, L.1, ITURRIAGA RAMIREZ, T.2, OJEDA VAN GEETERUYEN, C.2, BARCELÓ, O.2, QUESADA-GONZÁLEZ, C.3, LOPEZ-NEYRA, A.4, YVERT, T.1, PÉREZ-RUIZ, M.1,5, Institution: FACULTY OF PHYSICAL ACTIVITY AND SPORT SCIENCE, Country: SPAIN, Abstract-ID: 1141

INTRODUCTION:
Cystic fibrosis (CF) is a life-limiting genetic disease caused by a malfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, leading to progressive deterioration of multiple organs [1]. New CFTR modulators partially restore this function and improve survival [2, 3]. Most of the current evidence, largely observational, focuses on pulmonary variables [4]. However, physical fitness and strength—validated prognostic factors—remain essential in CF [5]. Exercise improves cardiorespiratory fitness and muscle strength in children with CF [6], but in the context of CF treated with Elexacaftor, Ivacaftor and Tezacaftor (ETI), there is still uncertainty about whether structured exercise interventions provide additional benefits in key prognostic outcomes. This study aimed to assess the effects of a structured, strength–focused telematic exercise program on physical condition and muscle function in children with CF treated with ETI.
METHODS:
A randomised, parallel, single-blind clinical control trial was conducted in 3 public hospitals in Madrid, Spain. Children/adolescents with CF on stable CFTR modulators therapy were randomly assigned to an exercise group (16 weeks strength-oriented virtual exercise training intervention, ~1h online supervised, twice/week), or to a control group following their paediatrician usual recommendations. Primary variables: peripheral strength, change in VO₂peak. Secondary variable: lung function (FEV₁ Z-score). Analysis: R; significance=0.05.
RESULTS:
46 children with CF on ETI were included (exercise n=20; control n=26). After the intervention, the exercise group showed a significant improvement in FEV₁ z-score vs. control (Δexercise=0.217; IC95%:-0.199 – 0.632 vs. Δcontrol=-0.492; IC95%:-0.848 – -0.135; p=0.007; η²p=0.0217 [small effect]). A significant increase in lower-limb isometric maximal strength was also observed (Δexercise=0.626; IC95%:0.204 – 1.049 vs. Δcontrol=0.054; IC95%:-0.232 – 0.339; p=0.022; η²p=0.124 [medium-large effect]). No significant group differences were observed for VO₂peak (p=0.496), consistent with findings from pre-CFTR modulators cohorts. VO₂peak remains a relevant prognostic marker and is expected to stay elevated in this population.
No serious adverse events related to the intervention were reported.
CONCLUSION:
A structured exercise program for children with CF receiving CFTR modulators improved lung function (FEV₁ z-score) and lower-limb strength, suggesting meaningful functional gains. VO₂peak did not change significantly, likely due to baseline values near predicted norms, indicating a possible ceiling effect. These findings support the use of exercise at this new stage, and we propose analysing strength as a health indicator in disease clinical follow-up.
Funding: Carlos III Health Institute, co-funded by the European Union (PI23/00299).
References:
[1] Elborn 2016; [2] Accurso 2014; [3] Merlo 2024; [4] Hernández 2023; [5] Hebestreit 2019; [6] García-Pérez-De-Sevilla 2022