Or if you have a short time to work out for this week. You can choose example 2 because vigorous activity is heavy work out and you can choose day that you want to work out but you still have to do Muscle Strengthening Activities 2 days a week . by 1 minute of vigorous-intensity activity is about the same as 2 minutes of moderate-intensity activity. So this week ,you work out total 75 minutes and Muscle Strengthening Activities 2 days a week.