Kids Have Stopped Moving Nationwide.

National Association for Sport and Physical Education.
The Fitness Equation: Physical Activity + Balanced Diet = Fit Kids.
Reston, VA: National Association for Sport and Physical Education, 1999. 

National Association for Sport and Physical Education.
2010 Shape of the Nation Report.

Huberty J, Siahpush M, Beighle A, et al.
Ready for Recess: A Pilot Study to Increase the Physical Activity in Elementary School Children.
Journal of School Health, 81:257-257, 2011. 

Active Kids Perform Better.

Grissom, J. (2005).
Physical Fitness and Academic Achievement.
Journal of Exercise Physiology, 8 (1), pp. 11-25

Aberg, M.A.I., Pedersen, N.L., Torén, K., Svartengren, M., Bäckstrand, B., Johnsson, T., Cooper-Kuhn, C.M., Aberg, N.D., Nilsson, M., and Kuhn, H.G. (2009). Cardiovascular fitness is associated with cognition in young adulthood. Proceedings of the National Academy of Sciences of the United States of America, 106 (49), pp. 20906-20911. 


Welk G. Cardiovascular Fitness and Body Mass Index are Associated with Academic Achievement in Schools. Dallas, Texas: Cooper Institute, March 2009
A comprehensive look at the issue can be found at Designed to Move: A Physical Activity Action Agenda, 2012.