RT Journal Article SR Electronic T1 Quadriceps muscle contractility and fatigability in cystic fibrosis (CF) patients JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP PA2240 DO 10.1183/13993003.congress-2015.PA2240 VO 46 IS suppl 59 A1 Samuel Verges A1 Mathieu Gruet A1 Nicolas Decorte A1 Laurent Mely A1 Jean-Marc Vallier A1 Boubou Camara A1 Sébastien Quetant A1 Bernard Wuyam YR 2015 UL http://erj.ersjournals.com/content/46/suppl_59/PA2240.abstract AB Aims and objectives: Recent discovery of cystic fibrosis transmembrane conductance regulator (CFTR) expression in human skeletal muscle suggests that CF patients may have intrinsic skeletal muscle abnormalities which may lead to functional impairments. This study aimed to determine whether CF patients have altered resting muscle contractility and greater muscle fatigability compared to healthy controls matched for age, sex and physical activity levels.Methods: Fifteen CF and 15 controls performed a quadriceps neuromuscular evaluation using single and paired femoral nerve magnetic stimulations at rest, during and after an isometric intermittent fatiguing task (5-s on/5-s off knee extensions starting at 10% of maximal voluntary contraction (MVC) with 10%-MVC increment every 10 contractions until task failure). Quadriceps cross-sectional area (qCSA) was determined by nuclear magnetic resonance imaging.Results: MVC and some indexes of muscle contractility tended to be reduced at rest in CF compared to controls (MVC: 197±76 Nm vs 245±101 Nm, P = 0.15; doublets 100Hz: 74±30 Nm vs 97±28 Nm, P = 0.06) but theses tendencies disappeared when expressed relative to qCSA. CF and controls had similar impairments in muscle contractility with fatigue, similar endurance and recovery.Conclusions: CF patients have slightly reduced muscle volume and strength and similar muscle endurance and fatigability compared to healthy controls. These results suggest quantitative (reduced muscle mass) rather than qualitative (intrinsic skeletal muscle abnormalities) muscle alterations in CF and further encourage the incorporation of strength rehabilitation programs aiming to increase skeletal muscle mass in these patients.