When Linda Mullenhour enters the pool, she takes control. All eight members of her class mimic her every move, listening to her verbal commands. “One, two, three, four,” she says, “and we’re going ...

The rhythm is gonna get you … in better shape. It’s a chilly January morning at the Knolls, a housing community for seniors age 62 and older in Melville, and residents in the clubhouse are three ...