Improving Comfort of Shoulder and Back Health in Children's School Bags: Examining Damper Shoulder Straps and Ergonomic Factors

This paper presents a study on the implementation of a damper mechanism in the shoulder straps of children's school bags, which is known in Japan as Randsel. The increasing size of textbooks and the need to carry tablet computers further emphasized the necessity for such improvements, particularly for younger elementary school children. To evaluate the effectiveness of the damper strap, a computer vision tracking method was employed. Six schoolchildren were selected as participants and instructed to engage in jogging and walking in place while carrying the Randsel on their shoulders. Three markers were placed on the participants' shoulder and at the top and bottom of the Randsel to facilitate tracking. Results indicated that conventional Randsel designs exhibited delayed up-and-down movements in response to the participants' body motions during jogging on the spot. This resulted in a downward pull on the shoulder when the body was in an upward motion and an upward pull when the body descended to the ground, thereby disrupting the jogging walk. In contrast, the newly invented damper shoulder strap synchronized the timing of the up-and down movements with the body's motion. The delay time of Randsel’s movement from body motion was significantly reduced.