How Recent Findings in Electromyographic Analysis and Synergistic Control Can Impact on New Directions for Muscle Synergy Assessment in Sports

Muscle synergy is a state-of-the-art method for quantifying motor control with multichannel electromyographic (EMG) recordings. Muscle synergies have been used in many sports-related applications, including swimming, baseball, basketball, and other sports, for a biomechanical description of sports movements, improving athlete performance, preventing injuries, and promoting synergy-based rehabilitation strategies. However, despite the fact that it is clear that, in many sports, the assessments based on multi-muscle analysis are crucial for performance, the practical impact of muscle synergies on sports practice has been quite limited. Thus, so far, the potential of muscle synergy in sports has been poorly explored. However, recent advancements in synergistic models may strongly impact the understanding of motor control in sports. We identified several margins for improvement, which include novel models and updated algorithms: the separation of the EMG components (phasic and tonic) leading repertoires of synergies for motion and holding posture; the choice of multiple synergistic models (spatial/temporal/time-varying and others); the connection of synergies with the task space and the consequent role of non-linearities; the use of computational models and digital twins; and the fields and sports in which synergies can be applied. In this narrative review, we discuss how the novel findings from the biomedical field may fill the gap in the literature for the extensive use of muscle synergies in sports with several applicative examples.