Martelli said in a statement he was "sickened that as an assistant coach I contributed in any way to an unacceptable culture," and he apologized to the players "from the bottom of my heart."
The news of Martelli's resignation came Thursday as pressure mounted on the university for further action.
New Jersey's two top legislators increased pressure today over the firing of head men's basketball coach Mike Rice.
Senate President Steve Sweeney (D., Gloucester) called for Tim Pernetti, the school's athletic director, to either resign or be fired.
"It is becoming abundantly clear that Tim Pernetti cannot remain in his position as athletic director at Rutgers. For the good of the school, its students and its faculty, he should either resign or be removed from his position immediately," Sweeney said a statement released Thursday afternoon. "This incident will continue to hang over Rutgers like a dark cloud for weeks, months and perhaps years to come."
Separately, Assembly Speaker Sheila Oliver (D., Essex) continued to call for hearings into the decision-making process, saying on ESPN that she expects them "in the next couple of weeks."
Oliver had issued a statement Tuesday supporting the decision to fire Rice over a video of him kicking and shoving players and making anti-gay slurs. She also proposed hearings to determine "why Mr. Rice was not dismissed sooner and how exactly that decision was made."
On ESPN's Outside The Lines program this afternoon, Oliver stated definitively that "I am going to have legislative hearings," leveraging the budget process if necessary.
"The first concern here is finding out exactly how the decision was made not to dismiss Mr. Rice late last year and allow him to continue overseeing college students," Oliver said in a statement Thursday. "The answers to questions on the state's investment in Rutgers athletics and state budget allocations could very well depend on that explanation from the Rutgers administration."
A spokesman for the university declined to comment on the statements by Sweeney and Oliver.
The increased pressure comes the day after Rice was fired. He had previously been suspended for three games, ordered to attend anger management counseling, and lost $75,000 in fines and lost pay.
He will collect a $100,000 bonus for lasting through the season, the university confirmed Thursday, because the bonus is contractually obligated. Rice's five-year contract included the bonus for completing the 2012-13 season, along with bonuses for winning games and graduating players. He was paid $662,500 last year.
The school has not held a press conference since the video's appearance Tuesday.
Contact Jonathan Lai at 856-779-3220, firstname.lastname@example.org, or on Twitter @elaijuh.
Inquirer staff writer Joelle Farrell contributed to this article, which contains information from the Associated Press.