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DENVER, Colo. – The head of a national cheerleading group says newly released video of a Denver teen crying while a coach and teammates hold her down into splits shows techniques that are outdated and damaging.

Cheerleading coach and administration association director Jim Lord says forcing athletes into painful stretching used to happen decades ago, but coaches are now required to learn safe stretching practices.

The video, obtained by the mother of one of the cheerleaders, shows eight cheerleaders at Denver’s East High School repeatedly being pushed into splits while teammates held their arms.

One girl begs the coach to “please stop.”

In a letter to East High School parents, Denver Public Schools superintendent Tom Boasberg said while the cheerleading coach Ozell Williams has been fired, four other district employees remain on leave during the investigation – principal Andy Mendelsberg, assistant principal Lisa Porter, assistant cheer coach Mariah Cladis and Denver Public School deputy general counsel Michael Hickman.

Boasberg wrote in part:

I want to be very clear that this technique is a dangerous and unacceptable. We do not permit forced split or any practice or technique that puts the physical safety or emotional well-being of any of our kids at risk.As a superintendent, as a father and as an athlete, they are deeply disturbing. What happened was wrong. Under no circumstances should a young person be in a situation where they are suffering physical or emotional harm. Under no circumstances should a young person be forced to continue any activity beyond the point they have expressed the desire to stop.”

Denver Public Schools and the Denver Police Department are investigating.This is a developing story. Stay with 8News online and on air for the latest updates.Never miss another Facebook post from 8NewsFind 8News on TwitterFacebook, and Instagram; send your news tips to iReport8@wric.com.