In the conduct of their daily duties, law enforcement officers (LEO) are often required to perform dynamic, physically demanding tasks with little or no notice, sometimes at maximal levels of exertion [1]. In order to perform these occupational tasks safely and effectively, LEOs need to not only be sufficiently fit but also the resilience to perform these tasks regularly without experiencing excessive stress [2]. Given these requirements, training for prospective LEOs must be rigorous enough to ensure that when trainees graduate, they are competent in their response to crisis and robust enough to maintain their capacity throughout the span of their career [2].
The applicant pool for LEOs is drawn from the general population, and despite general increases in population sizes, the numbers of individuals eligible to apply is shrinking [3]. Globally, the target age groups tactical organizations (such as military, law enforcement, etc.) seek to employ are representing a smaller percentage of the population. Additionally, western obesity and inactivity epidemics are further limiting the pool from which applicants can be drawn. For example, in the United States, 31% of individuals 17-24 years old interested in enlistment are ineligible for military service due to obesity alone [3] and overall, 71% of this age group are ineligible for service for one or more health or fitness related reasons [3].
On joining a law enforcement agency (LEA), new trainees may be subject to environmental stressors (such as relocation and sharing close quarters with strangers), psychological stressors (such as academic pressure, and disrupted sleep), and physical stressors (such as a sudden increase in physical training, and a lack of recovery time), and, as such, risk physical overtraining and consequent injury and illness [4]. These training factors generally represent a substantial increase in mental and physical for most trainees [5]. For trainees with lower levels of fitness, the increased physical work requirement has an even greater impact, as these trainees must consistently work at a higher intensity to complete the same task when compared to more physically fit peers [6]. It is therefore not surprising that less fit trainees may be at a greater risk of injury than their fitter counterparts [7], who are themselves three to five times more likely to sustain an injury than their fully trained counterparts [8].
Injuries in tactical training present a twofold problem for tactical organizations. Firstly, there are the intrinsic financial and time loss burdens the organization accrues [9]. Apart from the costs of any rehabilitation or compensation, it can cost an organization more than $85,000 AUD to identify a new trainee to replace the one lost due to training injury [10]. This need to replace the trainee introduces a second problem; finding a suitable trainee from the aforementioned shrinking pool from which applicants can be drawn [3]. Hence it is in the best interests of LEA to identify, recruit and train candidates with the highest chance of successfully completing training.
Previous research, primarily on military trainees, has identified that a fixed-distance, timed run is effective in predicting musculoskeletal injury in a variety of settings [11,12]. Other tests, mostly of muscle endurance, such as timed pushup [13,14] and situp [12,15] events, are less conclusive across studies but may still be valid predictors of injury in a police training setting. Two muscle fitness tests of strength (grip strength) and power (vertical jump) [6,16] have been identified as predictors of not only injury, but other tactically relevant outcomes such as escalation of force incidents in operational LEO [17].
However, the relevance of the above research, associating performance on a physical fitness test with risk of injury during training, may be highly dependent upon the environment. For example, if one training academy completes a high volume of pushups as part of their training, pushup performance may be a greater predictor of injury risk than a 5km run. The inverse may be true if the academy has a low pushup but high running requirement in its daily training. The disciplinary culture of an organization (assigning running laps of a building vs. pushups or situps as punishment) may contribute as well. Therefore, based on the crucial need for LEAs to retain personnel recruited for training, and the previously reported utility of fitness testing for predicting risk of injury in a given environment, the aim of this study was to investigate relationships between components of a physical ability test (PAT) and risk of injury during police recruit training in a cohort of New Zealand (NZ) Police trainees.