To answer the title question, you work out your body. That specifics of that question highly depends on your current situation. Like age, current fitness level, what you are training for (strength, cardio, weight loss, etc), and what you have access to.

I would hope that it would just be a playground just for adults. Don’t know why people just lose their spark for playground shenanigans in age. I would love to climb and jump around again. But there isn’t any place for that for adults.