Dr. Larry Nassar, 54, appears in court for a plea hearing in Lansing, Mich., Wednesday. (Paul Sancya/AP)

Former Olympic gymnastics team physician Larry Nassar, accused of sexual assault by more than 130 women, including several Team USA gymnasts, pleaded guilty to seven sexual assaults Wednesday in Michigan, in a deal that will send him to prison for at least 25 years.

The guilty plea to seven counts of first-degree criminal sexual conduct was the first admission by Nassar, a 54-year-old father of three and formerly one of the most respected sports physicians in elite gymnastics, that he was not performing legitimate medical therapy as he touched his victims, often without gloves.

"For all those involved, I'm so horribly sorry that this was like a match that turned into a forest fire out of control," Nassar said during the hearing in Lansing, not far from the clinic on the campus of Michigan State, where many of his accusers encountered him.

Nassar could be sentenced to up to 40 years for his admissions of guilt Wednesday, while also facing likely prison sentences in two other courts. Nassar faces similar charges in another county in Michigan, and a plea hearing in that case could occur next week, and he also faces a sentencing hearing in December in federal court, for three child pornography crimes he pleaded guilty to this summer.

Since one woman first publicly accused Nassar of assault in September of last year, dozens have come forward in lawsuits against him, USA Gymnastics and Michigan State, where he worked full time and treated local athletes at a campus clinic.

Several Olympic gymnasts have come forward alleging they were assaulted by Nassar, including McKayla Maroney, Aly Raisman and, just this week, Gabby Douglas.

While the criminal proceedings against Nassar could be nearing an end, the fallout from his case may continue for the two institutions facing dozens of lawsuits by victims: USA Gymnastics and Michigan State.

In March, USA Gymnastics chief executive Steve Penny resigned as he faced rising criticism for waiting five weeks in 2015, after receiving a complaint about Nassar, to inform law enforcement, and for not informing officials at Michigan State, where Nassar continued to work with young athletes until August 2016.

Nassar was a volunteer with USA Gymnastics, his time working with elite athletes covered as part of an "outreach" component of his job at Michigan State. USA Gymnastics ended the arrangement in 2015.

The Nassar case stoked outrage in Congress and led to proposed legislation, still under consideration in the House, to strengthen abuse prevention measures throughout Olympic sports organizations.

At Michigan State, officials have drawn criticism over allegations victims complained about Nassar's treatment as far back as 1997 but were assured they were receiving legitimate therapy.

In 2014, a woman filed a complaint about Nassar with the university's Title IX office, but that inquiry concluded the woman had misunderstood Nassar's treatment. Michigan State has commissioned an independent inquiry into how university employees handled allegations about Nassar but has set no timetable on when that inquiry will be complete, and university officials have said there are no plans to publicly release the inquiry's findings, citing concerns about the dozens of lawsuits the school faces.