The Structure of Functional Synergy That Ensures the Preservation of the Orthograde Posture in Humans

The paper considers the process of interaction of individual muscles and muscle groups serving various joints of the body in order to minimize vertical stability disorders caused by respiratory movements of the chest. The most significant control variables in the process of regulation of intermuscular interaction in order to maintain the stability of the vertical position of the body are considered. The analysis was performed using factorization of muscle electrical activity data, values of articular angles and movements of body segments. It was found that the strategy of maintaining a vertical stance is associated with the control of the hip and neck segments, and with an increase in the disturbing effect, other segments of the body are involved in synergy. An increase in the depth of breathing is accompanied by the inclusion of previously unused muscle modules and a change in the degree of involvement of each muscle in the process of regulating the vertical posture. Such inclusion is reflected in the temporal pattern of activation of synergies at the muscular level, which manifests itself in the formation of additional activation peaks in individual phases of the respiratory cycle. In the process of maintaining vertical stability, muscle activity is moderately associated with the regulation of the position of the general center of mass and is more directed at the formation of kinematic synergies, including changes in the values of a number of articular angles and simultaneous movement of most body segments. The latter, in turn, stabilize variables important for maintaining equilibrium, and synergetic control at the kinematic level increases as the depth of breathing increases.