National School Backpack Awareness Day 2007
Summary of the Literature from 1999 to 2002 on the Effects of Backpacks on Students
Prepared August 2002 by the Communications Group of the American Occupational Therapy Association (AOTA)
The majority of studies conducted on the effect of backpacks on human physiology have focused largely on the adult population. In recent years, researchers have begun to examine how school backpacks effect children and adolescents. A review of the research published within the past three years reveals that incorrect backpack use leads not only to back pain in youths, but also impedes proper physiological growth and functions.
As part of the Italian Backpack Study, Negrini, Carabalona, and Sibilla (1999) found that the average load students carried weighed 22% of their body weight, exceeding the recommended 15%. They also found that 34.8% of students carried more than 30% of their body weight at least once during the week.
Negrini and Carabalona (2002) in the Italian Backpack Study tried to identify school, family, and personal factors, such as the weight of the textbooks and which non-essential items are being carried, that may influence backpack weight. Of the participants, 79.1% felt that their bags were too heavy, 65.7% reported fatigue, and 46.1% complained of back pain. The back pain was associated with feeling fatigued during the carrying of the bag and the amount of time spent carrying the bag more than the weight of the bag. Negrini and Carabalona found that all involved (schools, parents, students) bear responsibility for the load carried, and all should modify current behavior to reduce the stress of the bags on students. Suggestions include having teachers take into consideration the weight of the difference subjects, "not only in terms of their intellectual content, but also in terms of the load they place on the shoulders of their students," to prevent students from carrying multiple heavy texts one night, and a very light bag the next; the researchers also recommend that parents monitor what their children carry to school each day.
"Although the relation between back pain and backpack carrying possibly will be disputed in the future," write the researchers, " when it comes to the quest to achieve 'occupational' conditions that are comfortable when we are well and accommodating when we are ill, we cannot go on ignoring our children."
The Italian Backpack Study also examined oxygen intake of students with and without a backpack on (Merati et al 2001). Researchers found that the weight of the backpack did decrease oxygen intake, but not excessively. When students wore a loaded backpack, they walked slower, but with longer strides. Over 80% of the students reported fatigue when walking while wearing a backpack. Back pain was more likely in less physically active students. Over 50% of students described having back pain in the last 2-3 years, and 17% reported back pain within the previous 17 days.
Lai and Jones (2001) studied lung volume data in students in Hong Kong. The average weight of a Hong Kong primary school student's backpack was 15% of the student's body weight. When the bag weighed 20% of the student's body weight, the researchers found lung volume was significantly compromised; when the bag weighed 10% of the student's body weight, however, lung function was not compromised.
The position in which a backpack is worn affects the impact the backpack has on the posture of the student wearing the backpack (Grimmer et al 2002). A study of 250 Australian students found that positioning the backpack on the upper spine has the largest negative effect on posture, which can effect the development of the spine. Lower positioning of the backpack approximates the body's center of gravity, and therefore has the least effect on posture.
A student in Houston (Iyer 2001) conducted a study comparing backpack weight in India and in Houston, and found that almost 60% of students aged 9 to 20 years old from both countries felt chronic back pain (Guyer 2001). When the backpack weighed 15% of their body weight or less, only 20% of students reported pain. Guyer cites a Finnish study of 1000 children (Taimela, Kujala, Salminen, Viljanen 1997) indicating that 1% of 7-year-olds have back problems related to school backpack weight, rising to 6% of the population of 10-year-olds.
Iyer examined the students to see if there is a correlation between back pain and Body Mass Index (BMI), weight carried, mood, strength, or body fat. Approximately half of the students in the study reported pain regardless of the weight carried, whether they exercised, or their mood. Students across the board reported pain, most in the shoulders and back. In studying surveys answered after students carried backpacks of a variety of weights, Iyer found that the less heavy the backpack carried, the less frequently pain was reported; however, the pain was never eliminated.
Feingold and Jacobs (2002) researched the effect of education about backpack safety on middle school students' behavior. In a study done in Boston, a group of students (the intervention group) was taught through videos, handouts, and demonstrations the proper way to load and wear backpacks, while the control group received no training. All members of the intervention group changed how they wore and loaded their backpacks. Though quantitative data showed no difference in the posture between the control and intervention groups, 78% of the intervention group reported feeling less pain in the back, neck, and shoulders, or less pressure and strain.
Chansirinukor, Wilson, Grimmer, and Dansie (2001) examined the posture of 13 Australian high school students under several load conditions: posture without a backpack, while carrying the bag on both shoulders, carrying the bag on the right shoulder only, a bag weighing 15% of the student's body weight, and after walking for 5 minutes. They examined posture from four angles, and found that carrying the backpack on both shoulders affects students the least. Weight in the bag causes students to lean forward to counteract the backpack, with a significant increase in angle when carrying a bag weighing 15% of the body weight. They also found that the longer a student walks with a loaded bag, the larger the angle becomes, negatively affecting posture and spine growth.
The adolescent spine continues growing in periodic spurts until the age of 18, making the proper use of backpacks vital. In a study of nearly 1200 Australian students, Grimmer and Williams (2000) found that more girls than boys complained of back pain, and those with back pain typically carried heavier packs in relation to their body weight than those who did not report pain. Also at higher risk of pain were students who did not participate in sports (though for students aged 12 and younger, the risk of back pain increased with sports participation). "Reports of adolescent spinal pain may well become reports of adult spinal pain in time," cautioned the researchers, "producing ready-made occupational health and safety risks in the workforce."
Chansirinukor, W., Wilson, D., Grimmer, K., & Dansie, B. (2001). Effects of backpacks on students: Measurement of cervical and shoulder posture. Australian Journal of Physiology 47, 110-116.
Feingold, A. J., & Jacobs, K. (2002). The effect of education on backpack wearing and posture in a middle school population. Work 18, 287-294.
Grimmer, K., Dansie, B., Milanese, S., Pirunsan, U., & Trott, P. (2002 Apr 17) Adolescent standing postural response to backpack loads: A randomized controlled experimental study. BMC Musculoskeletal Disorders 3(10).
Grimmer, K., & Williams, M. (2000 Aug). Gender-age environmental associates of adolescent low back pain. Applied Ergonomics 31(4), 343-360.
Guyer, R. L. (2001 Jan). Backpack = back pain. American Journal of Public Health 91(1), 16-19.
Iyer, S. R. (2001 Oct.). An ergonomic study of chronic musculoskeletal pain in schoolchildren. Indian Journal of Pediatrics 68(10), 937-941.
Lai, J. P., & Jones, A.Y. (2001 Apr). The effect of shoulder-girdle loading by a school bag on lung volumes in Chinese primary school children. Early Human Development 62(1), 79-86.
Merati, G., Negrini, S., Sarchi, P., Mauro, F., & Veicsteinas, A. (2001 Jul). Cardio-respiratory adjustments and cost of locomotion in school children during backpack walking (the Italian Backpack Study). European Journal of Applied Physiology 85(1-2), 41-48.
Negrini, S., & Carabalona, R. (2002 Jan 15). Backpacks on! Schoolchildren's perceptions of load, associations with back pain and factors determining the load. Spine 27(2), 187-195.
Negrini, S., Carabalona, R., & Sibilla, P. (1999 Dec 4). Backpack as a daily load for schoolchildren. Lancet 354(9194), 1974.