Clinical Chiropractic 2010 (Dec); 13 (4): 253–260
Johanna Schmidt, Sharon Docherty
It’s well understood that heavy backpacks are taking a heavy toll (excuse the pun!) on adolescent spines. A recent standing magnetic resonance imaging study by the Department of Orthopaedic Surgery, University of California, at San Diego revealed that: “Increasing backpack loads significantly compressed lumbar disc heights measured in the midline sagittal plane” and that: “student subjects reported significant increases in back pain, associated with increasing backpack loads from 4, to 8, and finally to 12 kgs of carried weight”.
This most recent novel study (see below) was performed with German primary school children.  Researchers wanted to determine whether giving the children rolling luggage, to carry their school books, might reduce spinal stress. As it turns out, what might work well for Mom at the airport does not work so well for Junior, lugging his books across uneven sidewalks, all the way to school. The authors had to conclude that: “This suggests that school children should use backpacks rather than trolleys when the weight is within recommended limits”.
Objective To investigate whether there is a difference in the posture of school children walking with a backpack versus pulling a trolley.
Design Comparative, controlled, pilot trial.
Setting “Grundschule Fallersleben” – primary school in Germany.
Subjects Thirty-four school children between 6 and 8 years of age.
Methods Initially, neutral posture was measured in a standing position. All children were then asked to walk a predetermined route without intervention for approximately 7 min. This was followed by walking the same route with either a backpack (n = 19) or trolley (n = 15). Deviations from neutral of the thoracic and lumbar spine (flexion, extension, lateral flexion and rotation) from the final 30 s of the imaging sequences were taken and analysed.
Results Compared to unburdened walking, walking with a backpack led to a statistically significant (p = 0.05) increase in thoracic extension (3.91°, 95% CI = 3.35–4.46) and right lumbar lateral flexion (2.29°, 95% CI = -3.41 to -1.18), and a statistically significant decrease of lumbar flexion (2.2°, 95% CI = 0.34–4.06). In contrast, walking with a trolley increased extension (1.4°, 95% CI = 0.72–2.08), right lateral flexion (1.24°, 95% CI = -1.91 to -0.57) and right rotation (3.09°, 95% CI = -3.85 to -2.32) of the thoracic spine, and led to a statistically significant increase in left rotation (3.57°, 95% CI = 2.58–4.55) of the lumbar spine. Comparing the backpack and trolley groups showed a statistically significant (p = 0.05) increase in thoracic extension and right lumbar lateral flexion in the backpack group. Posture during trolley pulling was characterized by a statistically significant (p = 0.05) increase in right thoracic and left lumbar rotation.
Conclusion Participants adopted asymmetric postures during walking with a backpack and pulling a trolley. However, the trolley group was characterised by spinal rotation which possibly adds an extra source of stress. This suggests that school children should use backpacks rather than trolleys when the weight is within recommended limits.