Fitness Activities for Children’s Enthusiasm

Since children can’t use any of the exercise machines, which activities can they do to increase enthusiasm in fitness? I know adults can “offer lessons to..” children using the punching bag (reward from Athletic career). I found that children swimming in a pool build up their body skill and fitness enthusiasm. Children can use the Ballet bar to build body skill, but it increases the music and dance enthusiasm rather than fitness. They can’t work out using the tv either. Are there any other fitness activities for children?