A smooth sustained contraction, with no evidence of relaxation, is called N fused, or complete, tetanus B) a twiteh Cl unfused, or incomplete, tetanus D) summing of contractions

In muscle physiology, fused tetanus occurs when a muscle is stimulated at a frequency that allows no relaxation between contractions, leading to a sustained and powerful contraction. This phenomenon plays a crucial role in activities requiring prolonged force, such as lifting objects or prolonged exercise, where rapid nerve impulses keep the muscle fibers continuously contracted, maximally engaging them. Fused tetanus was first studied extensively in the late 19th century, contributing to our understanding of muscle function and neuromuscular physiology. Early experiments by scientists like Hermann von Helmholtz helped clarify how muscles respond to stimuli, paving the way for advancements in both medical treatments for muscle disorders and athletic training techniques that enhance muscular endurance!