Correlations between Muscle Activities and Strap Length and Types of School Bag during Walking

Abstract

[Purpose] The purpose of this study was to examine correlations between muscle activities and strap length and type of the school bag during walking. [Subjects and Methods] The subjects of this study were 20 healthy students. An 8-channel electromyograph (8-EMG) (Pocket EMG, BTS, Italy) was used to measure the muscle activities of the right upper trapezius, left upper trapezius, right erector spinae and left erector spinae during walking with the bag. The collected data were analyzed using Kendall’s coefficient of concordance. [Results] The muscle activities of the right upper trapezius, left upper trapezius, right erector spinae and left erector spinae were significantly higher when walking with a shoulder bag than when walking with a backpack. No significant correlations were found between muscle activities and strap lengths of the bag. [Conclusion] While carrying a bag, the activities of the trunk muscles were influenced more by the type of the bag than by the strap length. These results indicate that a backpack is a better method of carrying a load than a shoulder bag.

Relationship between shoulder pain and weight of shoulder bags in young women

“…As regards the muscles directly affected by heavy bag carriage, excessive upper trapezius muscle activity has been observed in a study conducted with students (Yoon, 2014). The same study also reports lower muscle activity when walking with a backpack because of weight distribution on the shoulders.…”

“…DISCUSSION Some conditions imposed on the shoulder complex, such as the weight of a shoulder bag, can lead to functional and anatomical changes. There are many studies on the effects of backpack use (Yoon, 2014;Hardie, Haskew, Harris, & Hughes, 2015), particularly on schoolchildren (Dianat et al, 2011, Ries et al, 2012. However, there is a scarcity of studies on the use of female shoulder bag and on the maximum weight recommended to minimize the harmful and chronic impact on such joint.…”

“…Considering bag weight, most studies agree that people using backpacks should not carry a weight greater than 10% of their body weight (Hardie et al, 2015;Yoon, 2014;Qureshi & Shamus, 2012). However, there is a scarcity of studies on the maximum weight indicated for shoulder bags.…”

“…Among the risk factors for shoulder pain, the overload imposed on the joint and muscles by the use of some female accessories, such as bags and backpacks, is harmful to its structure (Bettany-Saltikov & Cole, 2012). In addition, the characteristics of these accessories (weight, size, shape, duration of carriage) and the physical constitution of women can lead to greater damages, such as changes in body alignment, displacement of the center of gravity, excessive shoulder muscle activity, fatigue, and pain (Yoon, 2014;Dianat, Javadivala, & Allahverdipour, 2011).…”

“…Several studies carried out with students have analyzed the weight of these accessories and demonstrated that school bags should not weigh more than 10-20% of body weight. An increase in these percentages could cause spine curvature disorders, bad posture habits, pain, learning Shoulder bag weight and shoulder pain | 41 impairment, and decreased quality of life (Yoon, 2014;Dianat et al, 2011). In addition, the frequent use of heavy backpacks has a cumulative impact on this population, leading to future health problems (Ries, Martinello, Medeiros, Cardoso, & Santos, 2012).…”