Cross Training: Teen Version: References

"Cross-training for Fun and Fitness - Cardiovascular Exercise - FitFacts." American Council On Exercise (ACE). Web. 15 June 2010. <http://www.acefitness.org/FITFACTS/fitfacts_display.aspx?itemid=2547>.

Kisner, Carol, and Lynn Allen Colby, Therapeutic Exercise: Foundations and Techniques, F. A. Davis Company; 5th ed, 2007