Students enjoying- see?- the NYC FITNESSGRAM test (Courtesy DOE)

Gov. Andrew Cuomo says he needs to trim fat from public budgets. Here's an unbeatable move: cut test-prep time in half and staff up physical education. The numbers prove that athletic testing creates confidence, while academic testing can leach it. And a student's rate of improvement on athletic tests predicts her rate of improvement on other tests.

A study published in ScienceDaily shows that students performed better on academic tests just after a bout of physical activity. And numerous studies show that the correlation persists across years: when students improve year over year on calisthenic scores, they also tend to improve their academic scores. New York City knows this. It just needs to be less shy about it.

The city school system, in 2006, adopted a fitness test called Fitnessgram that measures physical condition on five variables.

A multi-year study of roughly 200,000 students taking NYC FITNESSGRAM tests suggests a strong correlation between fitness and higher levels of math and literacy, says the head of fitness for the Department of Education, Lori Benson.

Young people benefit from exercise even if they go from sedentary to slightly active - and the means to this success can entail basketballs, yoga poses or Dance Dance Revolution units.  So Benson says the vital task for educators is to help young people find sports they enjoy enough to pursue on their own.

The variable to watch is improvement - not win-loss record or even total Body Mass Index (BMI).  A person's weight responds to a tangle of environmental and social factors, from the ubiquity of Dunkin' Donuts, to the scarcity of bikeways, to the prevalence of bad air quality in poor neighborhoods. But a child's fitness responds to the ways people teach her to concentrate her mind and respect her body. Schools can't change the outside culture - but they can and should change students' base fitness level.

That's an idea a governor - or, more locally, a cash-strapped principal - would be hard-put to dismiss in the quest for measurable gains.  "We can't necessarily hold principals accountable for BMI," says Benson, "but they can perhaps think about how fitness may be a performance measure."