earticle

영어

The purpose of this study was to investigate the change the muscle activity of the sternocleidomastoid and upper trapezius during a walking with the backpack of different weight. We recruited 20 healthy volunteers of male 11 and female 9. Backpack weight were prepared 10％, 15％ and 2 0％. the volunteers completed to walk at a speed of 4 ㎞/h on a treadmill for 1 min with the backpack of three different weight at three time. Surface electromyograms were recorded from sternocleidomastoid and upper trapezius for the change of muscle activity. EMG values were normalized by maximum muscle contractions (％maximum voluntary isometric contraction, MVIC). One-way repeated of ANOVA with post-hoc Bonferroni's correlation was used to compare activities according to the weight of backpack. Collected data were statistically analyzed by SPSS 19.0. The muscle activity of sternocleidomastoid muscle was significantly increased with backpack weight between 15％ and 20％(p<.05). The muscle activity of sternocleidomastoid muscle increased during walking with backpack weight between 10% and 15%. But there is no statistically difference( p>.05). The muscle activity of upper trapezius muscle was significantly decreased as backpack weight increases (p<.05). According to the results of this study, the muscle activity of neck flexor muscle was significantly increased as backpack weight increases. Therefore forward head posture is likely to be made by heavy backpack weight.