Penny resigned from his position in March of last year amid claims the organisation was slow to react to sex abuse allegations regarding former team doctor Larry Nassar.

He has been accused of "covering up" the claims against Nassar and of waiting nearly a month to inform authorities after he learnt about the accusations.

An e-mail revealed by the Senate subcommittee investigating the scandal allegedly shows that Penny asked six USA Gymnastics board members not to discuss the allegations against Nassar.

"You are instructed not to have any conversations with anyone concerning this issue until further notice," he reportedly said.

USA Gymnastics had claimed that they had been asked by the FBI not to discuss the case to avoid jeopardising their investigation.

But the e-mail was reportedly sent before the FBI became involved.

Penny is also accused of not informing Michigan State University where Nassar also worked and preyed on victims.

But he provided no insight in Washington D.C today by using the Fifth Amendment law which allows witnesses to decline to answer questions to protect against incriminating themselves.

Nassar has now been jailed for up to 175 years with Penny replaced as President by Kerry Perry.

"I would like to answer your question but I have been instructed by my attorney to assert my rights under the Fifth Amendment," Penny said in response to questions, according to NBC.

Senator Richard Blumenthal reportedly said that documents "would speak for you" in response with one e-mail allegedly referring to a "code of silence" about the affair.

Penny has denied any wrongdoing or any cover-up but an onlooker in the public gallery shouted "shame" at him as he refused to speak.

John Manly, an attorney for some of Nassar's victims, told NBC: "He lacks the common decency to cooperate with a US Senate committee that is trying to protect young athletes from sexual predators."

Blumenthal added: "Juries are instructed they should draw no conclusion from someone taking the Fifth but the popular impression is there's something to hide, and in many instances I think that's fair."

Rhonda Faehn, the former USA Gymnastics senior vice-president for the women's programme, did speak today at the hearing.

She was sacked last month and claimed she didn't know if this was because it was thought she was about to reveal information to the Senate hearing.

Faehn was reportedly the first person to hear a complaint about Nassar after coach Sarah Jantzi overheard a conversation between elite athletes Maggie Nichols and Aly Raisman.

"I immediately called Penny and told him in detail about the concerns Jantzi shared with me," Faehn said. 

"Penny told me he would call Jantzi and the parents of the gymnasts right away."

Faehn has been criticised for not going immediately to police but she alleged Penny had advised against it.

"He told me not to say anything or do anything because he was going to handle everything going forward," she said.

Ex-Michigan State President Lou Anna Simon was another witness today.

The University last month agreed to pay $500 million (£370 million/€423 million) to victims of Nassar.

A written statement was also accepted from former United States Olympic Committee (USOC) chief executive Scott Blackmun.

The USOC have also faced questions about what they knew and when.

Those who have accused Nassar include Olympic athletes on the American team, with dozens publicly testifying against him at his court hearings.