A former youth gymnastics coach who operated a gym in Rockland has pleaded guilty to sex abuse charges. The Rockland County District Attorney’s office says 67-year-old Joseph Lewin of Port Chester admitted to all of the allegations against him during a hearing last week. Lewin owned and operated “Joe’s Gym” in Hillburn and admitted to engaging in sexual contact with his victims between 2007 and 2014. He faces four years in state prison and five years post-release supervision when sentenced in September.