The sheriff's office said 25-year-old Yamilet Rubio Carcamo was arrested on Friday and charged with assault causing bodily injury by HCSO's Violent Criminal Apprehension Team.
The victim's family told ABC13 that the incident happened on April 21 at the Planet Fitness location off of Tomball Parkway and Louetta Road.
On Monday, the video that was sent to Eyewitness News showed the moment that Carcamo allegedly threw the employee to the floor and started punching her.
"It's definitely scary, I've never really been in a situation like this," the victim, who did not want to be identified out of fear of retaliation, said.
The victim's mother said they immediately filed a police report with the Harris County Precinct 4 Constable's Office and were later told the case was passed off to the Harris County Sheriff's Office.
"It's affected me because I can barely walk, I can hardly stand sometimes without my knee hurting or sending a shooting pain up my leg," the victim said.
SEE ORIGINAL REPORT: Surveillance video shows gym employee attacked in Tomball