The Stryd Training Plans by Steve Palladino are fully customizable. However, if you do not customize the plans, they will follow a Plan Default.
All of the Training Plans follow the same Plan Default. The plans are constructed on a default Monday-to-Sunday week format.
In race-specific plans (5K, 10K, Half Marathon, Full Marathon), the plans are constructed with a default Sunday “A” race. (the race plans include the entire taper through the Sunday “A” race)
If you wish to follow the Plan Default, install the plan on your calendar to start on a Monday and end on a Sunday.
These plans can be modified to adjust how the final week's payout. Even though the final week taper is specific to your race target plan, alternative final weeks have been written for the contingency of an "A" race that falls on a Sunday. (and in the case of marathon plans, the contingency of a Monday Boston Marathon “A” race).
You would install the plan on your calendar as if your race was on the Sunday nearest your actual A race, then delete the final taper week ending with an A race on Sunday, and finally, install the appropriate final taper week ending on Saturday (or Monday if running the Boston Marathon).
The alternate final week tapers are specific to your race target plan, your Level, and your runs/week option, and are available in the Stryd plan library.