00:07:16.770 Your knees are at 90 degree angles. 00:07:16.770 Your knees are at 90 diploma angles. The core is used throughout the day, whether you are cooking a meal, walking down the Subway stairs, sitting down, standing up, and so forth. It is used in easy, on a regular basis movements. The weaker your core muscles, the extra likely you are to slouch or hunch when sitting, standing or walking.