Fig. 1From: INSPIRA: study protocol for a randomized-controlled trial about the effect of spirometry-assisted preoperative inspiratory muscle training on postoperative complications in abdominal surgerySensitivity of the sample size with regard to the expected effect size, θ, given a within group standard deviation of 10. An example is shown for θ =6 and a power of 90 %. The curves are smoothed and shown for illustration onlyBack to article page