During the 1951–1977 period, electromyography matured into a systematic tool for mapping muscles' roles during movement, enabling researchers to link specific EMG patterns to functional actions and instigating clinical and rehabilitation uses. Methods based on surface EMG, isometric contraction, and signal averaging advanced quantitative relationships between muscle activity and force, supporting early biomechanical models of motor control. A unifying focus emerged on standardizing procedures and integrating physiology with movement science, fostering cross-disciplinary approaches to sensorimotor function.