The greatest benefit is not gained from exercise that is taken as play or exercise merely. There is some benefit derived from being in the fresh air, and also from the exercise of the muscles; but let the same amount of energy be given to the performance of helpful duties, and the benefit will be greater, and a feeling of satisfaction will be realized; for such exercise carries with it the sense of helpfulness and the approval of conscience for duty well done.
In the children and youth an ambition should be awakened to take their exercise in doing something that will be beneficial to themselves and helpful to others. The exercise that develops mind and character, that teaches the hands to be useful, and trains the young to bear their share of life’s burdens, is that which gives physical strength, and quickens every faculty. — Fundamentals of Chrisitan Education – Page Number: 418