'Terri' is a wearable walking assistance device for elderly dogs with reduced hind leg muscle mass. In companion dogs, weight distribution is predominantly 7:3 in favor of the front legs. By around age six, the less-exercised hind leg muscles begin to diminish, leading to health issues. To counteract this, 'Terri' uses actuators and resistance motors at the hip joint to reduce muscle strain during movement. Unlike traditional dog wheelchairs, 'Terri' helps maintain and enhance the dog's hind leg muscle mass.