There are many illnesses and diagnoses that can cause tight or weak muscles. As part of the initial evaluation, the physical therapist looks at muscles and joints and prescribes an exercise program if they are tight or weak. These exercises can be performed in many positions, such as standing, laying down or sitting. They may also use devices, such as weights or rubber tubes, to make the exercise more resistive. Depending on muscle strength and joint stability, physical therapists may also determine the need for an orthotic or a brace. If indicated, the physical therapist works with an orthopedic technician or certified orthotist to obtain the best fitting brace.