Experiment 2: Observations

All of the subjects in experiment 2 reported that it took less effort to bring themselves back to neutral with the backpack   carried high on the back, A than with it carried down low, B.  Conversely, the subjects reported that it required the most effort to support the load when it was furthest from the spine and furthest from the shoulder, D.

The observations in part 2 (based on the subjective assessments of a real backpack) contradicted in part the measurements made in experiment 1 (using the Spine Simulator).  The source of the contradiction is not obvious, although there is likelihood that some of the measured forces are in the same order of magnitude as the measurement accuracy of the Newton Scale.  Further investigation is required to resolve this conflict.

     Figure 34: Custom Backpack Load Positions