Protector or packhorse: the impact of stab resistant body armour and appointments on police performance
Dempsey, Paddy Carrick
Introduction: Despite being deployed to all frontline New Zealand Police in 2007, there are few studies that have investigated the influence of Stab Resistant Body Armour SRBA) and mandated appointments on officer function and safety. The aim of this study was to examine the influence that SRBA and the weight of mandated accessories have on simulated police tasks and physiological load. Secondary questions explored how participant relative weight carried, level of SRBA and appointment habituation, age, body size (BMI) and fitness level (VO2max) impacted on the magnitude of any loading effects. Methods: Fifty-two male participants (37 ± 9.2 yr, 180.7 ± 6.1 cm, 90.2 ± 11.6 kg, body mass index (BMI) 27.6 ± 3.1, mean ± SD) completed a VO2max test and task familiarisation. Two experimental sessions were completed (>4 days in-between) in a randomised counterbalanced order, one while wearing SRBA and appointments (loaded) and one without additional load (unloaded). During each session participants performed 10 functional tasks based on simulated police task elements. These were a timed balance task, an acceleration task to simulate exiting a car seat, pull-ups, a vertical jump (VJ), a drop jump concentrating on safe landing (DJ safe), a drop jump moving into a vertical jump (DJVJ), a drop jump landing with a distraction (DJ distr), a grappling task, a mobility task, and a 5-min treadmill run at 13 km.hr-1. One minute after the 5-min run, tasks 1-9 above were repeated in the same order. Results: Loading significantly decreased performance during each of the ten tasks (p > 0.001), with mean decreases ranging from 12-42% depending on the task involved. All mean peak vertical landing forces were significantly increased while participants were loaded, with increases from 13-19% (p < 0.001) depending on the type of landing involved. Following prior exertion, functional tasks were further decreased and landing forces further increased by 6-16% and 4-9% respectively. The distracted drop jump task had the largest and DJVJ the smallest mean increase. Participants carrying larger relative load were more negatively affected during the balance, pull-ups, DJ (safe), DJVJ height and 5-min run (p < 0.05). Participant level of SRBA and appointment habituation was only important during the balance, acceleration, VJ, DJVJ height and mobility tasks (p < 0.05). Due to interacting effects, the impact of participant characteristics remains inconclusive. The data, however, suggests that a combination of increasing age and BMI, and decreasing VO2max may increase the relative impact of loading effects on police performance. Discussion: The significant performance impairment caused by SRBA and appointments during simulated police task elements has potential implications for officer function and safety. An increase in peak vertical landing forces has been associated with a greater risk of lower limb and foot injury. However, the relative importance of each of these performance decreases to police work is likely to vary depending on a number of factors, including the law enforcement situation faced and interacting individual characteristics.
Advisor: Handcock, Phil; Rehrer, Nancy
Degree Name: Master of Physical Education
Degree Discipline: School of Physical Education
Publisher: University of Otago
Research Type: Thesis