Roger Clemens and his former trainer, Brian McNamee, testified at a Congressional hearing Wednesday on the Rocket?s alleged use of performance-enhancing drugs.

McNamee said he injected Clemens with performance-enhancing drugs more often than he previously claimed. He told the House Committee on Oversight and Government Reform that he injected Clemens 16 to 21 times with steroids and human growth hormone (HGH) from 1998 to 2001.

He also attacked Clemens' credibility. "While I liked and admired Clemens, I don't think that I ever really trusted him." The hearing became heated during several exchanges. At one point, Rep. Chris Shays (R-Conn.), attacked McNamee's character, calling him a drug dealer.

Clemens, a former Yankees pitcher and seven-time Cy Young award winner, repeated his denials under oath, possibly opening himself up to criminal charges if he's found to have lied.

"I have never used steroids, human growth hormone or any other type of illegal performance-enhancing drugs," Clemens said in a prepared statement. "No matter what we discuss here today, I am never going to have my name restored." The testimony comes after the release of former Sen. George Mitchell's report on performance-enhancing drug use in Major League Baseball. In a sworn affidavit, pitcher Andy Pettitte said Clemens admitted to using HGH during a conversation they had in 2000. Trainers and therapists at Norwalk's Moore Physical Therapy were glued to the televised hearing.

"I believe ? people are starting to understand the impact that it has on sports itself. It's bigger than sports now," employee Craig Wood said.

The congressional committee did not reach any conclusions, but members said the issue may be referred to the Department of Justice for a resolution and possibly criminal charges.To see the hearing, go to channel 612 on your iO digital cable box and select iO Extra.

AP wire reports contributed to this story.