Sampling and statistical analyses
The sample size was calculated using PASS (version 21.0.3; NCSS, Kaysville, UT, USA). With a significance level (alpha) of 0.05, using a one-sided two-sample unequal-variance t-test, group sample sizes of 36 and 36 achieved 99% power to reject the null hypothesis when the means of the compressing and no compressing disk groups were 27.91 and 18.85, respectively, with standard deviations of 10.54 and 8.45, respectively