Muscle activation characteristics of the front leg during baseball swings with timing correction for sudden velocity decrease.
This study aimed to clarify the activation characteristics of the vastus lateralis muscle in the front leg during timing correction for a sudden decrease in the velocity of a target during baseball swings. Eleven male collegiate baseball players performed coincident timing tasks that comprised constant velocity of 8 m/s (unchanged) and a sudden decrease in velocity from 8 to 4 m/s (decreased velocity). Electromyography (EMG) revealed that the muscle activation was typically monophasic when responding unchanged conditions. The type of muscle activation during swings in response to decreased velocity condition was both monophasic and biphasic. When biphasic activation appeared in response to decreased velocity, the impact time and the time to peak EMG amplitude were significantly prolonged and the timing error was significantly smaller than that of monophasic activation. However, the EMG onset from the target start was consistent both monophasic and biphasic activation in response to conditions of decreased velocity. In addition, batters with small timing errors in response to decreased velocity were more likely to generate biphasic EMG activation. These findings indicated that timing correction for a sudden decrease in the velocity of an oncoming target is achieved by modifying the muscle activation characteristics of the vastus lateralis muscle of front leg from monophasic to biphasic to delay reaching peak muscle activation and thus prolong impact time. Therefore, the present findings suggests that the extent of timing errors in response to decreased velocity is influenced by the ability to correct muscle activation after its initiation rather than by delaying the initiation timing of muscle activation during baseball swings.
Faculty of Health and Medical Sciences, Department of Sports and Health Sciences, Aichi Shukutoku University, Aichi, Japan.
Yoichi
Y
Ohta
Faculty of Sports Humanities and Applied Social Science, Department of Physical Education, National Institute of Fitness and Sports in Kanoya, Kagoshima, Japan.
Hiroki
H
Nakamoto
Department of Sports Science, Japan Institute of Sports Sciences, Tokyo, Japan.
Yasumitsu
Y
Ishii
Faculty of Sports Humanities and Applied Social Science, Department of Physical Education, National Institute of Fitness and Sports in Kanoya, Kagoshima, Japan.
Sachi
S
Ikudome
Faculty of Liberal Studies, National Institute of Technology, Kumamoto College, Kumamoto, Japan.
Kyohei
K
Takahashi
School of Sport and Health Science, Tokai Gakuen University, Aichi, Japan.
Norihiro
N
Shima
D001484:Baseball / Q000502:physiology*; D001696:Biomechanical Phenomena; D004576:Electromyography / Q000379:methods; D006801:Humans; D008297:Male; D063177:Pulse Wave Analysis; D052097:Quadriceps Muscle / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult