The aim of this study was to examine the organization of ball-catching movements with different biomechanical structures, which are among the profile elements in rhythmic gymnastics, based on common synergies. An additional goal was to identify specific synergies presumably formed during the performing of movements with increased coordinative complexity. Synergy parameters were derived from simultaneously recorded electromyographic (EMG) data from 16 muscles and joint angle kinematics; factor analysis and principal component analysis were applied. It was found that at the kinematic level, participants demonstrated similar motor control strategies for catching the ball. Interjoint coordination was structured into two modules, independent of the motor task’s complexity. The specificity of kinematic modules manifested in a shift of the main peak of interjoint interaction synchronization, driven by the subjective perception of the ball contact moment. At the muscular level, up to five muscle modules were identified, two of which were consistently present across different ball-catching movements. Their function is associated with generating active motions of the upper limb segments and stabilizing the shoulder girdle. The component composition of muscle synergies is largely determined by the movements’ biomechanical structure and the presence of a common subtask within them.
The article presents an analysis of postural and muscular synergies involved in the implementation of motor tasks to maintain the balanced position of an object in the hand while walking. During movement, electromyograms of the superficial muscles of the upper extremities were recorded and video recordings of body segment movements were performed. Synergy parameters were extracted from the recorded signals using factor analysis and the principal component methods. The assumption about the orientation of muscle synergies to stabilize the trajectories of the upper limb segments, which are important for the successful implementation of a motor task, was tested. A general postural synergy has been established that is used for various motor tasks, as well as higher-order synergies that fine-tune posture during movement. Four muscle synergies involved in controlling the movements of the upper extremity have been identified, two of which are the main ones. They are associated with compensation for balance disorders caused by the moments of placing the foot on the support, active extension of the lower limb in the knee and ankle joints. The spatial organization of muscle synergies shows individual strategies for using muscles in their structure, despite the fact that the same moments act as disturbing factors acting on the stabilizing system. Muscle synergies are activated at the moments of the greatest disturbing effect on postural stability and are aimed at stabilizing articular angles and trajectories of movements of the segments of the upper extremity.
The article presents the specifics of intra-, intermuscular, and cross-manifestations of impulse activity of various groups of afferents (Ia, Ib, and II) of the antagonist muscles of the bilateral lower legs when performing high-speed locomotor movements. The study involved 9 male athletes specializing in short-distance running who performed a locomotor test—pushing a passive treadmill belt for 10 seconds at the fastest possible speed. Electromyograms of the antagonist muscles lower legs (m. tibialis anterior, m. gastrocnemius med.) were recorded during running, followed by its processing in the MatLab program and calculation of the impulse activity of primary and secondary afferents using mathematical model based on the prediction of the triggering of muscle spindles. It has been established that high-speed running is a cross intramuscular EMG pattern of tension of the antagonist muscles of the bilateral lower legs with a transition to their relaxation, which depends on the phase of movement. Such muscle innervation in the individual phases of a high-speed running step was manifested by effective intermuscular coordination of the flexor and extensor in the phases of stance and swing of the right leg, pronounced reciprocal relations of homonymous antagonistic muscles of the lower leg in the phases of swing of the right and stance of the left legs. Intramuscular proprioceptive afferentation of the antagonist muscles lower legs of high-speed movement is characterized by the manifestation of strong impulse activity of afferents Ib, moderate afferents II and weak Ia afferents of flexors and extensors of the of symmetrical legs. A phase-dependent modulation of the intermuscular afferentation of the primary and secondary fibers of the flexors and extensors of the bilateral lower legs in the phases of stance and swing of a high-speed running step is shown. The cross-interactions of afferent activity of homologous muscles of the bilateral lower legs in different phases of movement, characteristic of a high-speed running step, have been established. The identified features of intramuscular, intermuscular, and cross-limb afferent activity during running reflect their key role in regulating the inhibitory interneuron network of the spinal cord, which maintains targeted muscle contraction and modulates motor output parameters as a whole. The supposed reflex mechanisms of high-speed locomotor movements are discussed on the basis of well-known phenomena associated with the interaction of various afferent inputs to the spinal cord neuronal apparatus in the system of lower leg antagonist muscles.
В настоящей работе представлен анализ научных исследований, посвященных использованию эргогенических средств в тренировочном процессе спортсменов. Обозначены основные средства, используемые в тренировочном процессе лыжников-гонщиков для развития выносливости. Проведенный анализ показал, что для достижения максимального эффекта в развитии функционального потенциала организма и специальной выносливости следует практиковать различные варианты дыхательных упражнений: задержки на вдохе, на выдохе, как в состоянии покоя, так и во время активных тренировочных нагрузок.
The article presents an analysis of the muscle synergies involved in making ball throws in different directions and from different starting positions. The study involved 6 highly qualified athletes engaged in rhythmic gymnastics. Electromyograms of the superficial muscles of the upper extremities and trunk were recorded synchronously during the movements, as well as video capture of the movements of body segments. Synergy parameters were extracted from the recorded signals using factor analysis using the principal component method. It has been established that individuals who have mastered a complex motor skill can demonstrate similar motor control strategies. This is manifested in the structuring of intermuscular interaction in the form of two general modules, the degree of involvement of muscles in which is highly similar in the implementation of different motor tasks. The first muscle module implements active movement of the upper limb by jointly activating the muscles of the forearm, shoulder and upper shoulder girdle, and also provides stabilization of the position of the trunk by synchronizing the activity of the muscles of the back and abdomen. The second muscle module is specific and is mainly associated with high involvement in the synergy of the muscles of the upper shoulder girdle and forearm for the implementation of exercises performed without visual control, or from starting positions that limit the mobility of certain parts of the body. Thus, the solution to the problem of coordination of many elements of the motor system may consist not only in reducing the number of executive organs—muscles involved in control, but also in organizing control variables in the form of modules at the kinematic level and their stabilization through muscle synergies.
