In Florida, 1 in 4 children is overweight or obese. To turn those stats around in the state’s most populous county, the Miami-Dade Parks Department teamed up with the University of Miami Health System to create Fit2Play, a daily after-school and summer program that serves 1,400 to 1,800 children daily in almost 40 parks throughout the county.

Though focused on physical activity, Fit2Play also teaches children other basics of a healthy lifestyle, including good nutrition and helpful study habits. Each day’s session begins with homework help, followed by games designed to build physical and social skills. Fees are on a sliding scale pegged to a family’s income. What makes this after-school program stand out, however, is the data proving it is “highly effective.”

Sarah Messiah, a research associate professor of pediatrics at the University of Miami, helped design Fit2Play and conducted an initial study of nearly 300 children, ages 6 to 14, enrolled during the 2010-2011 school year.  Almost all the children were black and Hispanic, drawn from underserved neighborhoods. At the beginning and end of the program, the kids underwent a series of measurements to determine fitness, including body mass index—or BMI—and blood pressure. Physical fitness was assessed by sit-and-reach tests, timed sit-ups and push-ups and a 400-meter run.

Today, the initiative is focused on improving schools, health and employment opportunities in Liberty City, a tall order for an area with 16,000 children spread out over 6 square miles. It hopes to succeed by transforming Liberty City block by block, starting with an “impact zone” of 29 blocks surrounding an elementary and middle school, and particularly the three blocks adjacent to those schools, where more than 600 children live. There the initiative runs early-learning centers, after-school and summer programs and workshops for parents. Staffers, working alongside residents, have rehabilitated a basketball court, organized daily trash pickup, set up a bike-sharing program and opened a community center, which many kids describe as their “safe haven.”

Every day, Gutierrez and her staffers go door-to-door reminding residents they are here to help. One of those residents, Alicia Wilson, said at first she and her neighbors were suspicious, but then realized the initiative wanted to work alongside them to transform the area, not tell them what to do. “Miami Children’s Initiative came in and made us want to do better as parents, made us want to do better as people, made us want to do better as a community,” she says.

Within five years, Miami Children’s Initiative hopes to ramp up dramatically, expanding its reach to 250 blocks. Gutierrez figures many of the children in the initiative’s programs today will be in college by then. “That’s when we know that we’ve been successful,” she says, “when there are thousands of kids from Liberty City in colleges and universities across the country."

It may be hard to imagine that residents of Miami-Dade County could have a difficult time finding places to exercise, given the region’s abundance of beaches and natural beauty. But a drive through some of the county’s underserved neighborhoods reveals a notable void: There aren’t enough safe parks and playgrounds.

Through a series of actions, Miami-Dade is changing that.  

The county is carving out more space for cycling by building nature trails and bike lanes throughout the city. New playgrounds have been added as well, and the Consortium for a Healthier Miami-Dade County is creating “pop-up parks” in urban neighborhoods that have little green space. These parks come to life when a team temporarily cordons off an area for a day, lays down mats and brings in play equipment—notifying the community with flyers.