After Klaus Park moved back into his and his family's old house, he became more organized about the activities he had to do during the day.
Since he was a teenager he had been practicing calisthenics to strengthen his muscles so that he would not have so many problems with muscle pain after heavy work and also to be more efficient, but after he moved into the apartment to live with Jayaa and Emma, he neglected this. Since his room in the apartment had a small space in which only his bed and the desk for his computer could fit, there was no room for him to do calisthenics and he didn't want to do it in the middle of the room, so he stopped doing it.
In fact, during that time in the apartment, Klaus neglected his entire health. He cut out essential meals, such as afternoon coffee, lunch, and his own diet, not to mention spending entire days in deep immersion.