Muscle synergy analysis of a set of lower extremity movements in quiet standing scenario: A preliminary study

Human joint movement is resulted from consequential contractions of multiple muscles, and the associated multiple muscles operate in a coordinate manner which is usually called muscle synergy. In a physiological sense, muscle synergy reflects the human muscles natural coordination patterns, driven by neural commands dispatched from the central nerve system (CNS). For different specific movement of human, the related muscle groups can present different coordination patterns correspondingly. This paper investigates the muscle synergy patterns with different movement in sagittal plane for one healthy subject during quiet standing scenario without disturbance of external force. Non-negative matrix factorization (NMF) algorithm is applied to extract the muscle synergies of eight muscles of lower extremity corresponding to specific movement, e.g., back leaning, squatting, and stepping. The paper analyzes the muscle synergy patterns considering combinations of knee and ankle joint flexion directions.