After a series of violent incidents on school campuses, public school officials here are considering the use of flexible plastic handcuffs on out-of-control students — from kindergarteners on up.

The Milwaukee School Board voted Thursday to begin training security staff members to use the plastic handcuffs, but the issue has provoked a heated debate between parents and administrators over how to provide a safe learning environment.

In October, a 15-year-old female student reportedly attacked the principal at Milwaukee’s Ronald Wilson Reagan College Preparatory High School. The principal sustained a compression fracture in her back and a concussion when her head was slammed against a wall.

In November, a 17-year-old male student allegedly sexually assaulted a female teacher in front of a class at Madison High School. And earlier in the school year, an assistant principal was assaulted by a student.

The issue of violence on school grounds took on an urgent tone this week with the Virginia Tech shooting rampage that left 33 people dead.

Critics of such handcuffing often cite injury risks: A student might accidentally be choked while being restrained, and the cuffs used too tightly might interfere with blood circulation or cut the skin.

In Milwaukee, discussion on whether to use cuffs on K-12 campuses began months ago, said Supt. William G. Andrekopoulos.

The debate reached a feverish peak Thursday when the Milwaukee School Board argued for nearly five hours over the handcuff resolution, which had been approved in committee.