When she heard about the Lynn Community Health Center’s family bicycle safety day Tuesday, Andrea Cox blasted out an email to fellow General Electric River Works colleagues and quickly received a dozen replies from fellow cyclists ready to volunteer.Cox, a quality manager, and Josh Antrim, a helicopter engine designer, spent the afternoon tightening brakes and handlebars, and handing out free helmets to more than 75 children who arrived at St. George Greek Orthodox Church’s parking lot on brightly colored bikes.”We have a bunch of cyclists at work, so we know safety is very important, and the biggest thing is a helmet,” Cox said.View a photo galleryMatthew Roy, 9, and other children spent the afternoon getting a quick bike tune-up and being fitted for helmets before pedaling through obstacle courses supervised by bicycle-mounted police officers wearing bright yellow jackets.Matthew knows wearing a helmet is important and he confessed Tuesday to a minor spill this summer on his bike with its big “Rip Claw Magna” logo painted on the frame.The Health Center hosted the safety day in recognition of National Health Center Week. Lynn parks and recreation workers assisted the River Works volunteers and police officers in outfitting and instructing kids who showed up for the event.”Every kid got a helmet whether or not they have a bike,” Center spokeswoman Cynthia Steger-Wilson said.Julianna Perry, 11, shares her bike with her cousin and Antrim showed her how to pump up its tires and adjusted a poorly centered brake pad.”My dad has shown me how to do some things, too,” Julianna said.Officer Michael O’Connell survived a childhood bicycle accident that, he said, occurred when he wasn’t paying attention in traffic. He spent Tuesday afternoon guiding kids through a short obstacle designed to improve their ability to ride along a straight line.During his patrols, O’Connell said he frequently sees children riding bicycles on local streets and in playgrounds and parks. Owning and using a helmet are critical safety requirements for young riders, said O’Connell.”A lot of kids can’t afford them, and a lot don’t have them,” he said.