2.6. Statistical Analysis
All data analyses in this study were conducted using IBM SPSS Statistics ver. 22.0 (IBM, Armonk, New York, NY, USA). The means and standard errors of all measurements were calculated. The sample size for this study was calculated using the G-Power program (University of Dusseldorf, Dusseldorf, Germany). We set the effect size at 0.2, power at 0.9, number of groups at 2, and number of measurements at 2 for two-way analysis of variance (ANOVA). As the study included a human intervention process, specifically during the COVID-19 pandemic, it was particularly difficult to recruit participants and maintain the study, hence the small sample size with a reduced 