Effect of the backpack load on students’ discomfort

Backpacks are very useful in our day-to-day life, work, offices, and school. Especially students carry backpack to school every day with heavy loads of textbooks, notebooks, and laptop. This is an increasing concern of students carrying heavy backpacks in most countries. From the article of Huntsville Hospital, in the United States around 79 million students carry backpack to school. In 2007, more than 23,000 backpack-related injuries were treated at hospital rooms, physician offices and clinics. The load exerted from the backpack is one of the reasons of variations in the cervical and shoulder posture and it is suggested that carrying a backpack weighing 15% of body weight will be heavy for adults. This study evaluates the effect of backpack loads on the user discomfort in neck, shoulder, upper back, lower back, and knee during a walking activity. For this experiment, 12 participants were selected in the age group of between 18 to 21 years old from Lamar University. The backpack load which is exerted by the backpack was independent variable. As per the research, 15% of total weight of the body is the standard weight to carry the backpack during walking activity. Since, we have considered 10%, 15% and 20% weights of the backpack to the total body weight of participants. The user discomfort is considered as dependent variable. The walkway was embedded with three force plates with various backpack loads (10%, 15%, and 20%). Participants were told to walk on defined route for 10 minutes. After each task, participants had 5-minutes break and were asked to rate their discomfort level. The same procedure was carried out for all participants and measurement data were collected.The result showed a significant main effect of backpack load on the user discomfort of neck, shoulder, upper back, lower back and knee. The user discomfort with 20% load was significantly higher than that with 10% load for all 5 body parts. During the experiment, it was observed that female participant who weighs in range of 100-120 lbs. were experienced most discomfort and not able continue experiment when the weight of the backpack was more than 15% of the total body weight. Whereas the participants with the range of body weight around 160-180 lbs. experienced less discomfort in their neck and shoulder throughout the experiment. In conclusion, the research found that the backpack load significantly affects the user discomfort when student walk carrying the backpack. The research should have practical meaning to decide the appropriate weight of the students’ backpack and develop a more user-friendly design.