ABSTRACT

　Kinematic-muscle synergy analysis is a method capable of estimating the functional role of muscle synergies in real space. This study aimed to clarify the spatial role of muscle synergies involved in the underwater dolphin kick for competitive swimmers using this method. Eight female competitive swimmers participated in the study. They performed 15-m underwater dolphin kick swims with maximum effort. During the trials, kinematic and electromyography data were collected. A mixed factor decomposition algorithm was used to extract the kinematic-muscle synergies involved in one cycle of the movement from both the electromyography and segment angle data. The results revealed that four participants controlled their movements using three synergies, while the remaining four used four synergies. Four synergies were classified as a result of grouping the extracted synergies: Synergy 1, active during the first half of the downkick; Synergy 2, active during the transition from the downkick to the upkick; Synergy 3, active during the middle of the upkick; and Synergy 4, active during the latter half of the upkick and involved in core movements. Therefore, it was suggested that the underwater dolphin kick movement in competitive swimmers is primarily achieved through these four coordinated actions related to the muscle synergies.

DECENTE SPORTS SCIENCE Vol.47/The DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE