The comparative behaviour of two combat boots under impact.

BACKGROUND Improvised explosive devices have become the characteristic weapon of conflicts in Iraq and Afghanistan. While little can be done to mitigate against the effects of blast in free-field explosions, scaled blast simulations have shown that the combat boot can attenuate the effects on the vehicle occupants of anti-vehicular mine blasts. Although the combat boot offers some protection to the lower limb, its behaviour at the energies seen in anti-vehicular mine blast has not been documented previously. METHODS The sole of eight same-size combat boots from two brands currently used by UK troops deployed to Iraq and Afghanistan were impacted at energies of up to 518 J, using a spring-assisted drop rig. RESULTS The results showed that the Meindl Desert Fox combat boot consistently experienced a lower peak force at lower impact energies and a longer time-to-peak force at higher impact energies when compared with the Lowa Desert Fox combat boot. DISCUSSION This reduction in the peak force and extended rise time, resulting in a lower energy transfer rate, is a potentially positive mitigating effect in terms of the trauma experienced by the lower limb. CONCLUSION Currently, combat boots are tested under impact at the energies seen during heel strike in running. Through the identification of significantly different behaviours at high loading, this study has shown that there is rationale in adding the performance of combat boots under impact at energies above those set out in international standards to the list of criteria for the selection of a combat boot.