2009 年 41 巻 3 号 p. 13-21
This study focused on the activity of the left trapezius muscles during two fundamental kendo strikes: the basic large shomen-uchi (straight attack to the head in which the shinai is swung in a large arch) and the competition-style small shomen-uchi (straight attack to the head in which the shinai is swung in a small arch). We used electromyography (EMG) to investigate differences between the muscle activity of high-level college kendoists who competed regularly on the college team and midlevel college kendoists who practiced with the team, but did not compete with it.
The participants were 10 high-level and 10 midlevel male members of the University of T(varsity)Kendo Club. Participants performed both the large shomen-uchi and the small shomen-uchi seven times each and completed a survey asking them to “indicate the groups of muscles you use during a large shomen-uchi and those you use during a small shomen-uchi. ”
We then described methods for instruction of the shomen-uchi based on results of the above investigation.
1. Duration of left trapezius muscle activity
For both groups of participants, the duration of EMG activity of the left trapezius muscles was significantly shorter in the small shomen-uchi than in the large one. Concerning the latter, no significant difference between groups was seen in the duration of muscle activity. However, in the small shomen-uchi activity, a significant difference was evident, the higher-level kendoists exhibiting longer durations of activity than the midlevel kendoists. In fact, no left trapezius muscle activity was recorded for 5 out of 10 midlevel players.
2. Perception of use of the left trapezius muscles