Case study: a novel biomechanical approach for evaluating extended body armor systems.

To combat the devastating effects of improvised explosive devices (IEDs), body armor that provides extended coverage has been developed. However, this extended coverage increases the armor's weight and may restrict movement. Throughout this case study, a novel technique to assess several armor systems was investigated. Four soldiers performed shoulder and trunk movements while wearing each of the six different armor inserts. Electromyography (EMG) was used to quantify muscular activity and inertial motion sensors were used to determine joint range of motion (ROM). Outcome measures included maximum ROM, integrated EMG, and the soldiers' subjective rankings. For the shoulder tasks, objective ROM and EMG measures were related to each other as well as to subjective rankings and armor material properties. Conversely, little agreement was found between measures for the trunk tasks. Results of this preliminary investigation indicate that combining shoulder ROM and EMG measures has the potential to provide an objective assessment of body armor systems.