Upper Darby Police Superintendent Michael Chitwood took the hit - and survived.

In front of a half-dozen TV cameras, the 64-year-old chief took a 1,200-volt charge from a Taser, an electrical stun gun used by police.

His head whipped back, his back arched, his mouth opened wide, and he yelled out a word not fit for print.

"It knocks you out, it hurts," Chitwood said once he was back on his feet.

The Police Department will soon have four of the weapons in the field, hence the experiment. Chitwood explained: "I wanted to see the impact it would be on an individual."

Initially, the Tasers will be deployed when there is a potential for violence, Chitwood said. At a cost of about $800 per weapon, only supervisors will carry them.

Chitwood was stunned in the back, as he was supported by two officers. After they lowered their writhing boss gently to floor, he lay face down for about 10 seconds recovering.

"My whole body just trembled. I lost control of everything," said Chitwood later.

When a Taser is fired, two small probes trailing wires shoot out and deliver a five-second electrical charge. The shock can penetrate through clothing. The range is about 35 feet.

Pain is only part of the effect, according to William P. Bozeman, an associate professor at Wake Forest University School of Medicine, who did a study on the health effects of the weapons that will soon be released.

The jolt causes all the muscles to contract, which most people cannot overcome, said Bozeman, who is also an emergency-room physician. "It makes it effective for the police."

Bozeman's study looked at 1,000 cases in six police departments across the country over a two-year period. In 99.7 percent of the cases, there were no injuries or only minor injuries such as abrasions. But Bozeman cautioned that people have suffered serious head injuries.

Amnesty International has recorded 300 deaths in the United States since 2001 where suspects who had been subdued with a Taser later died in police custody. Dalia Hashad, director of the Domestic Human Rights Program for Amnesty International, said in a "small percentage" of the cases, the coroners have found that the Taser was a contributing factor.

Chitwood said his department is aware of the risks, and safety guidelines have been developed for the officers.

Chitwood said the weapon has been found to reduce injuries to officers in the field by reducing physical encounters with violent subjects.

According to the Taser International Web site, the Cincinnati Police Department saw a 56 percent reduction of injuries to police officers and 35 percent decrease in injuries to suspects during the first year the department used the weapons.

In Philadelphia, all districts have the stun guns available for use by supervisors.

Contact staff writer Mari A. Schaefer at 610-892-9149 or mschaefer@phillynews.com.