Publications (27) View all
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Article: Action-perception coordination dynamics of whole-body rhythmic movement in stance: A comparison study of street dancers and non-dancers.
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ABSTRACT: This study investigated whether whole-body, rhythmic action-perception coordination in stance is organized in terms of dynamic principles. We observed whether phase transition and hysteresis occur during the execution of dancing movements. Nine skilled street dancers and 9 novice controls performed 2 types of rhythmic knee-bending movements to a metronome beat in the standing position. Participants performed down-on-the-beat (in which knee flexion coincides with the beat) and up-on-the-beat (in which knee extension coincides with the beat), which are both typical components of street dance. All participants were instructed not to intervene in the pattern change. The auditory stimulus beat rate increased or decreased between 60 and 220 beats per minute (bpm) in steps of 20 bpm. We calculated the phase angle of beat time that is superposed on knee movement trajectory on a phase plane. Under the up-on-the-beat condition, phase transition and hysteresis were observed. The bifurcation frequency at which phase transition occurred significantly differed between groups, indicating that dancers were able to perform up-on-the-beat at higher movement frequencies than non-dancers. This suggests that dynamical properties may differ between Dancers and Non-dancers. The present results provide additional evidence that whole-body action-perception pattern formation is governed by general and common dynamical principles.Neuroscience Letters 04/2013; · 2.11 Impact Factor -
Article: Relationship between muscle cocontraction and proficiency in whole-body sensorimotor synchronization: a comparison study of street dancers and nondancers.
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ABSTRACT: In this study, we investigated muscle cocontraction during a street dance movement task to provide evidence that the level of muscle cocontraction is associated with degree of proficiency in whole-body sensorimotor synchronization movement. dancers and nondancers were required to synchronize a knee-bending movement in a standing position to a metronome beat. The dancer group showed significantly smaller variability of temporal deviation (defined as the peak knee-flexion time minus beat onset time), and lower level of muscle cocontraction analyzed by electromyographic data of the agonist and antagonist muscles of the upper and lower leg than did the nondancer group. In addition, multiple regression analyses revealed that the group effect significantly predicted the level of muscle cocontraction. These results show that the level of muscle cocontraction in the lower limbs during whole-body sensorimotor synchronization movement is associated with the degree of proficiency of the movement.Motor control 01/2013; 17(1):18-33. · 1.53 Impact Factor -
Article: Relationship between Muscle Co-contraction and Proficiency in Whole-body Sensorimotor Synchronization: A Comparison Study of Street Dancers and Non-dancers.
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ABSTRACT: In this study, we investigated muscle co-contraction during a street dance movement task to provide evidence that the level of muscle co-contraction is associated with degree of proficiency in whole-body sensorimotor synchronization movement. Skilled street dancers and non-dancers were required to synchronize a knee-bending movement in a standing position to a metronome beat. The dancer group showed significantly smaller variability of temporal deviation (defined as the peak knee-flexion time minus beat onset time), and lower level of muscle co-contraction analyzed by electromyographic data of the agonist and antagonist muscles of the upper and lower leg than did the non-dancer group. In addition, multiple regression analyses revealed that the group effect significantly predicted the level of muscle co-contraction. These results show that the level of muscle co-contraction in the lower limbs during whole-body sensorimotor synchronization movement is associated with the degree of proficiency of the movement.Motor control 09/2012; · 1.53 Impact Factor -
Article: Electromyographic analysis of lower limbs during baseball batting.
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ABSTRACT: We investigated the muscle activation pattern of lower limbs in baseball batting by recording surface electromyography (sEMG) from eight muscles, the left and right rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (MG) muscles. The muscle activities were compared between ten skilled baseball players and ten unskilled novices. The batting motion was divided into 7 phases, waiting, shifting body weight, stepping, landing, swing, impact, and follow through. The timing for these phases was analyzed by using a high-speed video camera. The onset latencies of sEMG were significantly earlier in baseball players at the left-RF (p < 0.01), right-BF (p < 0.05) and left-BF (p < 0.01). The peak amplitudes of sEMG activity were greater in skilled players at the right-RF (p < 0.01), right-BF (p < 0.01), left-BF (p < 0.01), left-TA (p < 0.01), right-MG (p < 0.01), and left-MG (p < 0.05). The timing for shifting, stepping, and landing was also significantly earlier in skilled players (p < 0.05, p < 0.01, and p < 0.05, respectively). Our findings suggest that preparations for the swing are made earlier in skilled baseball players, who recruit their lower muscles for the swing more effectively than novices.The Journal of Strength and Conditioning Research 06/2012; · 1.83 Impact Factor -
Article: Electromyographic activity of lower limbs to stop baseball batting.
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ABSTRACT: We investigated the muscle activation pattern of the lower limbs for the stopping motion of baseball batting by recording surface electromyography (EMG) from 8 muscles, the left and right rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (MG) muscles. First, muscle activities for 'Swing' and 'Stopping' trials were examined in 10 skilled baseball players and 10 unskilled novices. Second, the characteristics of EMG activities for 'Stopping' were compared between the 2 groups. The peak latencies of EMG were significantly shorter in 'Stopping' than in 'Swing' at the right-TA, left-BF, and left-MG between both groups. The peak amplitudes of EMG activity were significantly larger in 'Swing' than in 'Stopping' at the right-TA, left-BF, and left-MG in both groups. In addition, the peak amplitudes of EMG activity for 'Stopping' were significantly larger in the players than in novices at the right-RF and right-TA. The characteristics of EMG activity clearly differed between 'Swing' and 'Stopping,' and between baseball players and nonplayers, indicating that evaluating the EMG activity in batting enables the understanding of proficiency. Our findings should help players, novices, and coaches to optimize batting performance.The Journal of Strength and Conditioning Research 06/2012; 26(6):1461-8. · 1.83 Impact Factor
