Some interesting answers can be found below: 

• I use my leisure time to exercise so that I can maintain my stamina for my work. 

• I train and enrich my mind through conferences and reading. 

• I pursue activities different from my work. (I make pottery, I listen to music, etc.)

• I use my free time for reading. 

(Mention sports or cultural activities you enjoy. However, if you participate in an extracurricular activity that might be seen negatively by the employer, do not discuss it.)