von Foerster, M.: Our Kids, Backpacks, and the Back Epidemic. Orthopaedic Practice, Vol. 15;3:03
This article was written in 2003, before the BackTpack was created. Von Foerster had been concerned about the issue of backpacks and posture of school children. She was invited to contribute her observations and suggestions to the American Physical Therapy Association's Orthopaedic Section journal which was doing a focus issue on the backpack problem. This article includes analysis of the problem and suggestions of solutions at home, at school, and with public policy. Click here to download the article.


Hansraj KK, Hansraj JA, Griffin-Hansraj MD, Kiernan J, Subesan N, Firtat B, Elsisi A. Backpack Forces on the Spine 2018 Nov 11;33:361-365. Click here to view the abstract.

Dalia Mohammed Mosaad, Amr Almaz Abdel-aziemPostural balance and neck angle changes in school children while carrying a traditional backpack versus a double-sided bagBiomedical Human Kinetics, 10, 59–66, 2018  This study compared the body balance and neck angle differences in children when carrying a traditional backpack versus a double-sided bag. Conclusion: Carrying the double-sided bag restores the body balance and head posture to a condition that is similar to the no load condition. Download a PDF of the full article.

Calvo-Muñoz et al.: Prevalence of low back pain in children and adolescents: a meta-analysis. BMC Pediatrics 2013 13:14.
Low back pain often begins in childhood, and in adolescents the prevalence is similar to that of adults and is increasing.  Low back pain causes limitations in carrying out activities, school absenteeism and the reduction or ceasing of physical activity. Click here to view the article.

C. M. Weaver, C. M. Gordon, K. F. Janz, H. J. Kalkwarf, J. M. Lappe, R. Lewis, M. O’Karma, T. C. Wallace, B. S. Zemel, "The National Osteoporosis Foundation’s position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations" , Volume 27, Issue 4, pp 1281–1386. Abstract: Bone mass is built throughout childhood. This process is especially rapid during adolescence, reaching a peak shortly after peak height. By 4 years following the peak in height, 95 % of adult bone mass has been achieved. This period of rapid bone growth is the crucial "time of both opportunity and vulnerability for optimizing peak bone mass.” The National Osteoporosis Foundation "recommend[s] lifestyle choices that promote maximal bone health from childhood through young to late adolescence and outline[s] a research agenda to address current gaps in knowledge. The best evidence is available for positive effects of calcium intake and physical activity, especially during the late childhood and peripubertal years—a critical period for bone accretion." Download a PDF of the full article.

Kimberly D. DahlHe WangJennifer K. PoppD. Clark Dickin, "Load distribution and postural changes in young adults when wearing a traditional backpack versus the BackTpack" Gait & Posture (March 2016) Volume 45, Pages 90-96. Click here to view the abstract.

Kimberly D. Dahl, Henry Wang, and D. Clark Dickin of Ball State University, Muncie, IN, USA : Abstract of Presentation at the  2015 American Society for Biomechanics, "Postural Changes in Young Adults When Wearing a Traditional Backpack Versus the BackTpack”  Click here to view the article.

Valérie Lavigne, DC, "Weight limit recommendation in backpack use for school-aged children" Journal of Clinical Chiropractic Pediatrics, Volume 14, No. 2, March. Click here to view the article.

Frances Kistner, PT, PhD, CEAS; Ira Fiebert, PT, PhD; Kathryn Roach, PT, PhD; James Moore, PT, PhD "Postural Compensations and Subjective Complaints Due to Backpack Loads and Wear Time in Schoolchildren" Pediatr Phys Ther 2013;25:15–24. Click here to view the article.

M Ramprasad, Jeba Alias and AK Raghuveer "Effect of Backpack Weight on Postural Angles in Preadolescent Children" (2009)
Carrying a backpack weighing 15% of body weight change all the postural angles in preadolescent children. Click here to view the study.

von Foerster, Marilyn Miller, PT, MA "Student Test of Back-T-Pack." (2004)
BackTpack®to 40 middle-school students between the ages of 11 and 14, and monitored their reports of pain and postural changes compared with conventional backpack use. Click here to view the study.

Siambanes, David, DO, Martinez, Jason A, MA, Butler, Edgar W., PhD and Haider, Thomas, MD. "Influence of School Backpacks on Adolescent Back Pain." Pediatric Orthopedics (March/April 2004)

Johnson J, King C. "Backpain prevalence correlated with adolescent backpack use." Unpublished doctoral thesis. Forest Grove, OR: Pacific University. (2003)

Lamar S, Yu B. "The effect of backpack weight on forward trunk lean in school-age children: A two-dimensional videographic analysis." Phys Ther Case Rep. (2000) 3 (1): 28-31.

Pascoe DD, Pascoe DE, Wang YT, Shim D, Dim CK. "Influence of carrying book bags on gait cycle and posture of youths." Ergonomics. (1997) 40(6): 631-641.

*Applied Ergonomics
Volume 27, Issue 5, October 1996, Pages 315-320
Ergonomic investigation of letter-carrier satchels: Part II. Biomechanical laboratory study
C. Joe Lin*, Patrick G. Dempsey, †, , James L. Smith†, M. M. Ayoub† and Tracey M. Bernard§
* Chung Yuan Christian University, Department of Industrial Engineering, Chung Li, Taiwan
† Liberty Mutual Research Center for Safety & Health, Hopkinton, MA 01748, USA
§ Murray State University, Department of Occupational Safety & Health, Murray, KY 42071, USA
Received 10 May 1995. Available online 17 February 1999.

A biomechanical investigation of four satchels designed for the purposes of manually carrying and delivering mail was conducted. Twenty United States Postal Service carriers participated in the study. The satchels differed primarily in the presence/absence of a waist belt, the number and design of the shoulder straps, and the number of pouches. The biomechanical analyses were comprised of postural (shoulder and hip) deviation measurements, estimated compressive forces at the l5/s1 joint, soft tissue pressure on the shoulder, spinal torsion during mail retrieval, force distribution between the feet, and an anthropometric evaluation. The results indicated that a satchel with two shoulder straps and two pouches was more desirable than the single-pouch satchels from a biomechanics standpoint.

*International Journal of Industrial Ergonomics
Volume 23, Issue 4, 15 March 1999, Pages 269-279
Evaluation of satchels for postal letter carriers
M. M. Ayoub* and James L. Smith
Institute for Ergonomics Research, Department of Industrial Engineering, Texas Tech University, Lubbock, TX 79409-3061, USA

A research project funded by the United States Postal Service surveyed letter carriers to evaluate three alternative satchel designs and the current satchel. The evaluation consisted of both field surveys and a laboratory study. Each satchel had positive and negative attributes. A two-pouch system (satchel C) that distributed weight on both sides of the body, proved to be the best alternative in the laboratory study.However, concerns regarding the use of satchel C for defense against a dog attack made its desirability questionable in the survey. The study showed that none of the four satchels was a universally accepted alternative. Recommendations are offered to improve the satchel design.

The study examines four satchel designs that were evaluated for the US Postal Service. Similar techniques could be used to evaluate industrial designs for tools, equipment, clothing, or other work items.

Harreby M, Neergarrd Ke, Hesselsoe G, et al. "Are radiographic changes in the thoracic and lumbar spine of adolescents risk factors for low back pain in adults?" Spine. (1995) 20:2298-2302.

Miller M, Medeiros J. "Recruitment of Internal Oblique and Transversus Abdominis Muscles During the Eccentric Phase of the Curl-Up Exercise." The Journal of the American Physical Therapy Association
(August 1987) 67(8). Click here to view the study.