Motion and EMG Analysis of Soccer-ball Heading for the Lateral Direction
Shunsuke Sunami and Takeo Maruyama
[Received December 7, 2005 ; Accepted October 29, 2007]
This study investigated neck and trunk muscle activities and head-trunk motion during the action of heading a soccer ball in the frontal and lateral directions. Kinematic data were collected by three high-speed-video cameras, and then the head-rotation and trunk-twisting angles in the phase of back-swing, forward-swing and follow-through were calculated. The electromyographic (EMG) activities of four bilateral muscles (the sternocleidomastoid, trapezius, external oblique and erector muscles of the spine) were recorded and the peak-time-lag was calculated to evaluate the stability of the head. The peak-time lag was the lag between the greatest activation point of the right side and left side muscles. The variation of head-rotation angle showed a significant difference between the two conditions (P<0.05). In the sternocleidomastoid and trapezius, the peak-time lag was not significantly different between the two directions. From the results of this study, when skilled players headed the ball in the lateral direction, head rotation occurred in the back-swing, with trunk lateral bending to impact the ball in the forward-swing with muscles surrounding the neck activated to stabilize the head, and then in the follow-through, back muscles were used to prevent the body falling forward. We considered that these patterns of skilled heading motion are useful for coaching and for injury prevention.
Keywords: heading motion, muscle activity, three-dimensional analysis
[Football Science Vol.5, 7-17, 2008]