They are "jogging" on the playground.

Jogging refers to jogging or jogging, which is a physical activity of running or jogging on the playground. The term "jogging" originated from the word "jog", which means to run at a slow and steady pace.

Example sentence in Engpsh:

They enjoy jogging on the playground every morning before school.
The children are jogging around the track to keep fit.

Example sentence translation in Chinese:

他们每天上学前在操场上慢跑以保持健康。
孩子们在跑道上慢跑以保持健康。