Studies show that girls between the ages of eight and twelve are still receptive to adult influence, while beginning to feel peer pressure. It is a period in our emotional and intellectual development when we become aware of and begin to recognize important life and relationship issues. In addition, learning to value physical activity early in life increases the likelihood of participants staying physically healthy into adulthood. Studies show that those who develop exercise habits by their teen years are most likely to maintain those habits for life. Regular, moderate exercise improves cardiovascular functioning, reduces the risk of developing breast cancer, osteoporosis and obesity and positively counters the effects of depression and anxiety.

Children’s bodies are well suited for endurance exercise, and numerous studies have shown that children show many positive physiological adaptations to endurance exercise training. The keys are gradual progression and common-sense adult supervision. If those conditions are met, running 3 miles is a reasonable goal for most young people.
-Russell R. Pate, Ph.D., Department of Exercise Science, University of South Carolina