Methods
QuadGard Body Armor Systems
A 2 _ 3 design with two independent variables (i.e., ballistic material and armor system) was used in
this study. The independent variable ‘‘ballistic material’’ has two levels: Dyneema and Kevlar. For
the same level of protection, different layers of Dyneema and Kevlar were used. Dyneema has fewer
layers than Kevlar. The independent variable ‘‘armor system’’ had three levels: QG II, QG IV Not
Ventilated, and QG IV Ventilated. QG II featured the least amount of coverage and QG IV covered a
larger amount of body surface than QG II. QuadGard systems QG II and QG IV were originally
designed to feature sewn-in ballistic panels but were modified for this study to allow for the insertion
and removal of the two different test ballistic materials. The layers of ballistic material were stitched
together to make them insertable to simulate the original design. Ventilation of ‘‘QG IV Ventilated’’
was accomplished by folding open the upper flap located on the outer side of each front thigh piece
of QG IV. The overall system weight of QG II is 10.481 kg with Kevlar as the ballistic material and
4.458 kg with Dyneema as the ballistic material. The overall system weight of QG IV is 11.895 kg
with Kevlar as the ballistic material and 5.078 kg with Dyneema as the ballistic material. The Quad-
Gard armor systems, QG II and QG IV, are presented in Figure 1. To imitate the application of Quad-
Gard system in real-world situations, a standard ensemble including the standard issued battle dress
uniform (BDU) jacket, BDU pants, and Interceptor vest was always placed underneath the Quad-
Gard system during the test.