Influence of the increasing weight of the backpack on the balance of movement to primary school students

Nowadays, the backpack is becoming more and more important in people's daily life in our society. It has aroused the concern of the community that primary school students carry heavy bags. Heavy loading may cause some problems, like spinal, shoulder and back pain, etc. Consequently, it will affect the growth and development of students directly or indirectly. Thereby, the aim of this paper was to understand the influence of increasing the weight of the backpack on the balance of movement, and to explore the effect of heavy loading on the growth and development of those subjects. 100 healthy primary school students (7-12 years old) were recruited and they were guided in walking with a backpack loading of 5%, 10%, 15%, 20% and 25% body weight. Their kinematic and kinetic data were measured by Footscan plantar pressure system and 3D motion capture. Parameters of center of pressure and vector angles within two lower limb joints were calculated to quantify the relationship between the loading and balance. Our results show that an increase of weight of the backpack has limited effect on the track of the center of pressure, and pupils can cope with the balance risk brought by the increase of load. In order to maintain balance control, students adjust their posture to eliminate the balance risk factors caused by loading. While increasing of loading had a great effect on body posture, 15% BW (Body Weight) loading could be considered to be a safe value.