Schools in Massachusetts will be subject to new limits on physically restraining or isolating public school students under reforms ushered in late last year.

School staff members will no longer be permitted to pin students face-down on the floor in most instances and will need a principal's approval to keep children in a "time out" away from class for more than a half-hour. The changes -- which will be phased in this fall and officially take effect in January 2016 -- also require state officials to collect comprehensive data on how often schools restrain or seclude students and how often someone is hurt as a result.

Massachusetts' reforms were shaped, in part, by a June story by ProPublica and NPR that showed physical holds and isolation remain common in public schools across the country. Our analysis of federal data revealed these techniques were used more than 267,000 times in the 2012 school year, with some schools employing them dozens – or even hundreds – of times.

There's a growing awareness that, in some cases, children can suffer serious injuries and lasting trauma from such treatment. At least 20 children have died while being held down or left alone in seclusion rooms.

Spurred by tougher state and federal regulations, as well as professional standards, psychiatric and health care institutions have worked diligently over the past decade to limit their use of restraints and seclusion.

But rules governing public schools have remained more scattershot. The U.S. Department of Education issued restrictions, but made them voluntary. State and local authorities passed a patchwork of regulations that left dangerous techniques illegal in some places but perfectly acceptable in others. For instance, some states don't let schools use restraints that can restrict breathing – such as face-down "prone" restraints –on any children. But others do.

Massachusetts followed few of the half-dozen best practices for safe use of restraints and seclusion outlined in the federal guidelines and a proposed national reform bill, ProPublica's reporting showed. The Disability Law Center, an advocacy group, pointed out in a white paper submitted to officials reexamining Massachusetts' rules that the state compared poorly to its New England neighbors.

James DiTullio, the state's undersecretary of education, said former Gov. Deval Patrick's administration and education officials felt the rules were "long overdue for a very serious and thorough review."

The state sought advice from parents, students, public schools and private schools that serve public school students to determine what needed to change. ProPublica's report "very much played a helpful and informational role as that process got off the ground," DiTullio said.

The state's proposal was not without controversy, drawing 130 comments.

Representatives of several private and public schools said they opposed banning prone restraints outright, which the state initially proposed. Some of the actions prohibited by the new rules are needed to ensure students' safety, warned the Providers' Council, an industry group for private providers of health and human services. In the end, the state agreed to continue to permit prone restraints – with a doctor's approval – in rare circumstances.

The Massachusetts Association of School Superintendents was glad to see the exemption, said Christine McGrath, the group's director of operations.

The group was less pleased, she said, with new requirements for reporting and reviewing restraints, which superintendents will likely find burdensome, and also with limits on "time outs." "The reality," McGrath said, "is sometimes it takes more than 30 minutes for a child to de-escalate and to regroup."

Still, others, including advocates for the disabled and some parents, applauded the changes.

One parent told education officials how her son had suffered during prone restraints, saying the reforms should go further. "I told them I couldn't breathe and they just said you can breathe if you can talk," the son recounted, according to a summary of comments submitted. "They don't understand. I have a very short neck and I am very large and I get panicked when I am afraid I cannot breathe."

Rick Glassman, director of advocacy for the Disability law Center, said the center has heard many such stories from Massachusetts parents and children.

One child was so traumatized by being held face-down on a soiled carpet that he went home and barricaded himself in his room with furniture, refusing to return to the school, Glassman said. Another child was treated for post-traumatic stress disorder as a result.

Massachusetts' new rules also increase training requirements for school staff members and mandate that schools convene a team to come up with a plan for any student restrained multiple times in a single week.

One of the most significant new requirements is that schools report all restraints and restraint-related injuries to the state. In the past, only some were: Numbers reported in Connecticut, which requires schools to tally all restraints, suggest that as many as 90 percent of Massachusetts' holds were going unreported, Glassman said.

DiTullio said the new data collection provision will provide educators with a critical tool.

"We will learn so much more about how these restraints are being used, who they are being used on, how often they are being used," he said. "Good data leads to better outcomes."