noun. one of many contractile filaments that make up a striated muscle fiber.
1. Cardinal number Creatine may cause dehydration, due to its ability to hydrate your skeletal muscles as a result of a process called myofibril hydration. 2. Noun, singular or mass Creatine has the ability to pull water from the plasma in your blood stream into your skeletal muscles in a process called myofibril hydration, or muscle hydration.