BOC Domain 4 Treatment and Rehab – Therapeutic Modalities Practice Test

Fiber characteristics are shaped by diameter, myelination, and how fast they conduct impulses, which also hints at their function. The largest, heavily myelinated fibers conduct most rapidly—roughly 5–120 m/s—and include both sensory and motor types. This is the description that fits the large-diameter, fast-conducting fibers, which can carry either sensory information (like fine touch and proprioception) or motor commands to skeletal muscle. A small unmyelinated fiber would be slow (C fiber), and saying “only motor” or “only sensory” ignores that these large fast fibers can serve either role depending on the specific fiber.