What is the term used to describe the pattern in which muscles work together to produce body movement?

The correct term that describes the pattern in which muscles work together to produce body movement is "muscle synergy." Muscle synergy refers to the coordinated action of multiple muscles working in concert to achieve a specific movement, demonstrating how different groups of muscles can simultaneously contract to produce smooth and efficient motion. This concept is crucial in understanding human biomechanics and optimizing performance in running and other physical activities.

While "kinetic chain" encapsulates the broader idea of how different segments of the body interact and transfer forces to facilitate movement, it does not specifically pinpoint the collaborative actions of muscle groups. "Force coupling" refers to how muscles produce balanced movements through opposing forces, an essential component of muscle synergy, but again, it does not define the overarching concept. "Motor unit activation" pertains to the recruitment of muscle fibers within a single muscle rather than multiple muscles working together.

Therefore, the most accurate term to describe the collaborative function of muscles in producing movement is muscle synergy.