Introduction: Military and law enforcement personnel carry external loads as part of occupational requirements. The purpose of this program of research was to investigate load carriage within these populations with specific focus on occupational performance.
Methods: Prospective data for 218 (♀ = 9:♂ = 209) soldiers carrying webbing and pack, six (♂ = 6) specialist police officers wearing body armour and 11 (♀ = 5:♂ = 6) general duties officers wearing four different load configurations (Individual Light Armour Vest [ILAV] types A–C or stationwear) were analysed. Institutional ethics approvals were gained prior research commencement.
Results: The mean absolute load carried by soldiers over a 10-year period was 47.7 ± 21.0 kg (mean range over 10 years = 40.7–50.9 kg), by specialist police was 22.8 ± 1.8 kg (range 20.6–25.6 kg) and by general duties police was 8.69 ± 0.68 kg to 11.53 ± 0.77 kg (range = 7.40–12.7 kg) depending on ILAV type. Female soldiers reported carrying significantly lighter absolute loads (26.4 ± 13.3 kg) than their male counterparts (p = .045). However, no significant differences were found when the loads were considered relative to body weight (♀ = 43 ± 21% BW: ♂ = 47 ± 21% BW). In general police officers there were no significant differences in absolute or relative loads across the four different load conditions, but female officers (mean ranges = 13–17% BW) typically carried heavier relative loads than male officers (mean ranges = 10–14% BW). For marksmanship tasks, soldiers considered that their loads had a small negative impact on their marksmanship ability. Specialist police officers employing both primary and secondary weapons reported no significant differences in marksmanship, yet, individually, there was a weak to moderate negative correlation between perceptions of load carriage impacts on performance and actual marksmanship scores (primary r = −0.347: secondary r = −0.631) and this varied depending on marksmanship plane (x versus y-axis). General police officers performed similarly in three different ILAV and in standard station wear (p = .118). Of note, the officer's perceptions that they shot better with ILAVB compared to all other conditions was accurate.
Conclusion: While soldiers perceived mobility to be the most impacted by load carriage, this was observed to be the case in a specialist but not general police victim drag. The loads carried by soldiers and law enforcement officers vary widely. The impacts of loads on occupational task performance also vary, with the available research suggesting heavier loads have greater performance impacts.