Muscle activation refers to the process by which motor units within a muscle are recruited to generate force and movement. This process involves the electrical stimulation of muscle fibers by the nervous system, leading to the contraction of the muscle. Research in this area focuses on understanding how muscles are activated during different movements, exercises, and tasks, as well as how factors such as fatigue, injury, and training can influence muscle activation patterns. By studying muscle activation, researchers aim to improve our understanding of human movement and performance, as well as develop more effective strategies for rehabilitation and sports performance enhancement.