Coactivation refers to the simultaneous activation of two or more muscles or muscle groups during movement. It is an important concept in biomechanics and exercise physiology and is often used to describe the coordination of muscles during various movements. Some common synonyms for coactivation include coordination, synergism, integration, and synchronization. These terms are often used interchangeably to describe the same phenomenon, but they may be more specific in certain contexts. For example, synchronization may refer to the precise timing of muscle activation during a movement, while integration may refer to the interaction of multiple systems, such as the nervous and musculoskeletal systems, to produce coordinated movement.