The effect of common school bags on elementary school girls’ trunk muscles electrical activity

Various methods for educational devices carrying, have different effects on student physical pain perception and muscles, skeletal, cardio vascular, respiratory and metabolism performances. So this research is conducted to review the school common bags carrying (hand bag, shoulder bag and backpack) on elementary school girl students body muscles electrical activity. This research subjects are selected (one school randomly) from hamedan city elementary grade girl students. Their body muscles electrical activities include: spine erectro muscle(ES), rectus abdominis (RA) bilateral, are recorded for each student by using EMG unit after carrying each one of these bags that weight about 10 percent of their body weight for 15 minutes on treedmile with a speed of 1/1 m/s and one minute standing. Finding showed that shoulder bag carrying result in dissimilar activities of left and right parts of two ES, RA muscles. Hand bag carrying results in increasing this dissimilarity in left and right parts of RA, ES muscles, so that EMG activity level in RA, ES muscles opposite direction increased sighificantly and it reduced significantly in the other direction. During backpack carrying EMG activity of RA muscle is reduced in a significant and dissimilar wayand it reduces in a significant and similar way in ES muscle. As result backpack carrying in comparison to the hand bag and shoulder bag lead to similar more and activity less.