One-minute sit-to-stand test is practical to assess and follow the muscle weakness in cystic fibrosis

BACKGROUND: Quadriceps muscle weakness and reduced exercise tolerance are prevalent and associated with a worse prognosis in patients with cystic fibrosis (CF). The one-minute sit-to-stand test (1STST) has been proposed to evaluate functional exercise capacity and quadriceps strength. RESEARCH QUESTION: The aim of the study was to verify the relationship between the 1STST and the maximal isometric voluntary contraction of the quadriceps (MVCQ) evaluated by the dynamometer in stable patients with CF and to evaluate the impact of intravenous (IV) antibiotherapy. METHODS: Dynamometer and 1STST were performed in stable patients with CF at a routine visit, the admission and the discharge of an IV antibiotherapy. Patients wore an activity monitor during 72 h during IV treatment. RESULTS AND SIGNIFICANCE: 51 stable patients with CF at a routine visit and 30 treated with IV antibiotherapy were recruited. In stable patients, the 1STST was reduced to a mean of 2101 nxkg (657—SD), representing a median of 79% (7; 142—min; max)) of the predicted values (%PV) as well as the MVCQ to 78.64 N-m (23.21; 170.34), representing 57%PV (26). The 1STST was correlated to MVCQ (r = 0.536; p < 0.0001) and lung function (r = 0.508; p = 0.0001). Over the IV antibiotherapy course, the 1STST improves significantly like lung function and body mass index while a positive trend for MVCQ was observed. The gain of 1STST was correlated to the change in MVCQ (r = 0.441; p = 0.02) and was significantly higher in hospitalized patients versus home therapy. The 1STST is a good alternative to the dynamometer to evaluate and assess muscular weakness for the routine visit and IV antibiotherapy. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12931-022-02176-6.