Experiment 2: Using a Real Backpack

Apparatus: The Custom Backpack

In this experiment, an actual backpack belonging to the researcher is used.  The backpack is compartmentalized by putting cardboard boxes to expand and fill as much of the space within the whole backpack as shown in figure 27.

Real weights are now able to be distributed within the backpack based on the cardboard compartments.  For the experiment, 20 kg of dumbbell weights are used as the load.

Experiment 2: Procedure

           Using the custom backpack, the 20 kg weights are either put in a box compartment closest to the back of the backpack (ie, “weight is closest to spine”) or in a pouch at the front of the backpack (ie, “weight is furthest from the spine”).   For each of these 2 cases, the backpack’s straps are either adjusted to the short strap position (ie, “weight is closest to shoulder”) or to the long strap position (ie, “weight is furthest from shoulder”).

Figure 27: Backpack with Cardboard box Compartments

Seven people are asked to wear the backpack and assess their relative effort in carrying the load in the four different load distributions.  The individual subjects are asked to rank from 1 to 4 their effort to support the load (1 being the most effort to support the load to 4 being the least effort).  Figures 29 to 32 shows the 4 different load distribution cases, A, B, C and D.

Figure 28: Distributing Weights within the Backpack