According to researchers from the University of North Carolina at Chapel Hill School of Public Health,

Children play harder and longer when their child-care centers provide portable play equipment such as balls and jump ropes, more opportunities for active play and physical activity training and education for staff and students…

Of course, some school officials believe that any game that requires a ball is dangerous and exclusionary, so do not expect universal acceptance of the findings. And everyone knows that jump ropes can be used for all sorts of nefarious activities. The obvious solution is the cordless jump rope.