A police officer shown in leaked CCTV footage punching a woman has been withdrawn from public duty.
The Independent Police Complaints Commission (IPCC) has launched an investigation into the incident.
South Yorkshire's Chief Constable, Meredydd Hughes, said Pc Anthony Mulhall had not been suspended as the full facts needed to be uncovered.
CCTV footage showed Toni Comer, 20, being forcibly restrained after being ejected from a Sheffield nightclub.
'More to story'
Mr Hughes added: "The officer draws a salary from the public purse and we will make use of his expertise and talent.
"But I don't want him put in a position where his welfare will be put at risk because he'll be dealing with the public. And also I want public confidence restored.
"The public needs to understand that there is more to this story, a full independent investigation must take place in order that the full facts can be placed before the public."
South Yorkshire Police referred the matter to the IPCC on Thursday.
Nicholas Long, IPCC Commissioner for Yorkshire and Humberside, said an independent investigation would be conducted.
Mr Long said: "I have seen the CCTV footage and decided it is in the public interest for a wholly independent investigation to be conducted.
"This investigation will look into the circumstances of the incident to determine whether the force used by the officer when making the arrest was justified and proportionate."
The CCTV footage, obtained by the Guardian newspaper and shown on BBC Two's Newsnight, shows Ms Comer and a police officer falling down a flight of stairs outside Sheffield's Niche nightclub.
Police had been called when Ms Comer vandalised a car after being thrown out of the club.
At the bottom of the stairs, she is restrained by officers, with the officer she fell with punching her five times. It is not clear where he punched her.
The footage shows Ms Comer, from Sheffield, writhing around on the ground, which she said was due to an epileptic fit. Police said she was trying to resist arrest.
She is later dragged to a police van with her trousers round her knees.
'Cuts and bruises'
Ms Comer said on Thursday that she was "very surprised by the media frenzy" over the footage.
"People are quite shocked that police would do that to somebody and hope they'll get what's coming to them", she added.
Earlier, she had told BBC's Newsnight programme: "I got quite a few cuts and bruises on my arms and my face and the back of my neck.
"I really don't believe it. I didn't think they would actually do something like that at all."
On Wednesday, at Sheffield Magistrates' Court, Ms Comer admitted criminal damage to a car, which she said happened after she was ejected from the nightclub where she had been drinking brandy and had become aggressive.
She was given a conditional discharge and ordered to pay £250 to the vehicle's owner.
A South Yorkshire Police spokesman said: "It's a matter of record that the officer involved has fully accepted striking the person in the course of arresting them for an offence for which they were convicted.
"The officer maintains that he did so because the offender was assaulting him."
In a statement, Pc Mulhall said: "As her hands became free she tried to grab handfuls of my genitals and knee and kick me in the same place."
He said he had punched her to subdue her and then to "deaden her arm".