This is the fourth week of the swimming BASE PHASE which is used to build the aerobic capacity. Longer duration workouts at slower pace and intensity are predominant.
The focus of today is strength training. Strength training includes yoga, stretching, core exercises as well as weights. Days are identified but this can be done in smaller “doses” throughout the week.
You are building a swimming aerobic base and getting stronger.
Ideally you are at least stretching everyday after your other workouts. Your Day Off should be a day off but if really motivated, perform non-aerobic activities.