Students stand and move with backpacks that may be heavy, posture and balance may be altered. The purpose of this study was to determine if posture or postural stability change with back pack weight, the type of backpack worn or the location of the backpack on the spine. To measure posture and postural balance during three types of tests: static, dynamic and fall forward. Static tests were performed without a backpack, and with three backpacks, each tested in two different locations (high on the back; low on the back) with three different loads (no weight; 10% of the bodyweight; 20% of the bodyweight). Results indicate that postural stability and body position while wearing a backpack weighing 20% of the body weight are significantly different from conditions is which no backpack or a backpack with 0 or 10% of the bodyweight is worn. Standing with a back pack weighing 20% of the bodyweight results in an anterior movement of the shoulder and head, an increase in the movement of the center of pressure and an anterior, superior movement of the center of gravity. The location of the backpack also significantly altered postural stability and posture. When the backpack was worn in the high position, postural stability, as indicated by decreased movement of the center of gravity within the base of support, was greater than the low position but the head was in a more anterior position. In addition to the changes resulting from increase backpack weight and backpack location, the study found evidence that gender, body mass index and age may also alter stability and posture when wearing backpacks. These potentially at risk populations should be studied further to identify risks of injury and falls.
Weight, location, type of backpack, postural stability