Why do parkour athletes need to do strength and cardio training ?

Seeing much of this joylessness, and inaptitude, both of body and mind, for a lot which would be full of blessings for those prepared for it, we could not but look with deep interest on the little girls, and hope they would grow up with the strength of body, dexterity, simple tastes, and resources that would fit them to enjoy and refine the western farmer's life. which best describes fuller's style in this passage?