[The influence of backpack weight in school children: gait, muscle activity, posture and stability]. / Einfluss des Schulrucksackgewichtes bei Grundschulkindern: Gang, Muskelaktivität, Haltung und Stabilität.

BACKGROUND: Wearing a school backpack every day may cause postural problems and affect the gait pattern of children and adolescents. The aim of the present study was to analyze the influence of a 4 kg backpack load on the gait pattern and postural sway. OBJECTIVES: The aim of the present study was to analyze the influence of a backpack load of 4 kg on the gait and postural sway of elementary school children. MATERIAL AND METHODS: In this prospective study, a group of 12 elementary school children aged between 7 and 10 years without neurological or orthopedic problems participated. The measurements included a clinical examination, three-dimensional gait analysis with electromyographic recordings and measurement of postural sway on a force plate. RESULTS: The backpack load, on average 15% of the body weight, led to a slower walking speed, shorter step length and increased double-support phase. Increased anterior pelvic and trunk tilt, as well as hip flexion were also observed. Furthermore, the muscle activity and postural sway of the children were affected by the increased load. CONCLUSIONS: School backpacks weighing 4 kg caused changes in gait, muscle activity, posture and stability in elementary school children. Due to the weight of the backpack, the centre of mass shifted backwards and the children became less stable. During gait, this was compensated by increased anterior pelvic and trunk tilt and increased hip flexion. The activity of the paraspinal muscles was decreased and indicates that the backpack is carried passively. This may cause a negative long-term effect.