Feasibility of the A-STEP for the assessment of exercise capacity in people with cystic fibrosis

Refereed/Peer-reviewed Objectives: To evaluate feasibility of the Alfred Step Test Exercise Protocol (A-STEP) for the assessment of exercise capacity in adults and children with cystic fibrosis (CF); in adults to test whether demographics and/or lung function correlated with exercise capacity Methods: Adults and children with stable CF from two centres completed the A-STEP (a recently developed incremental maximal-effort step test). Feasibility was evaluated by: usefulness for exercise capacity assessment (measures of exercise capacity were: level reached, exercise-induced desaturation, and achievement of at least one maximal effort criteria); safety; operational factors; time to complete; floor and/or ceiling effects. We used multiple linear regression to test whether demographics and/or lung function correlated with exercise capacity Results: A total of 49 participants: 38 adults (18 male), percent predicted (pp) forced expiration in one second (FEV1) 29–109, aged 22–48 years and 11 children (6 male), ppFEV1 68–107, aged 10–15 years were included. Levels reached (mean (SD) [range]) were 10.2 (2.4) [6–15] (adults), 10.1 (2.5) [7–14] (children); desaturation (change between baseline and peak-exercise SpO2): was 8.4 (3.8 [0–15]% (adults), 2.0 (2.0) [0–7]% (children). A total of 8 (21%) adults and no children desaturated