You can change the start of your training week to Sunday or Monday in Final Surge.
After you log into Final Surge, click on "Settings" in the upper right-hand corner under your profile image to be taken to this page: https://log.finalsurge.com/UserProfile.cshtml
In the User Settings section, you'll see a button called "Edit Settings". Click that button and change the "Start of Week" option to "Monday" or "Sunday".