(49) A PILOT ANALYSIS OF THE INFLUENCE OF LOWER-BODY STRENGTH AND POWER DURING LAW ENFORCEMENT TASKS UNDER LOAD

Introduction: Many law enforcement agencies require recruits to complete assessments that test their underlying fitness characteristics as they relate to job tasks. These tests are administered without personal protective equipment (PPE typically 8-10 kg of added external load). PPE load could lead to a decrease in task performance. In this pilot study the decrease between unloaded and loaded performance is referred to as the tactical deficit. Lower-body strength and power could mitigate the tactical deficit created by PPE.

Purpose: To examine the effects of load carriage during policing tasks and investigate whether dynamic and isometric lower-body strength or power can lessen the tactical deficit.

Methods: Ten college students (7 males, 3 females) from one university were recruited and age-matched to typical law enforcement recruits. This pilot study comprised of three sessions across three days. Session 1 consisted of a standing broad jump (SBJ), isometric leg/back dynamometer (LBD), and a one-repetition maximum hexagonal bar deadlift. In sessions 2 and 3, subjects completed four police tasks either loaded or unloaded: a vertical jump, 75-yard pursuit run (75PR), a 9.75-m body drag (BD), and a 500-yard run. In the loaded condition, participants wore 8-10 kg of mandated officer PPE. Additionally, a vertical jump in the unloaded condition was included as part of the power measures. Dependent t-tests calculated differences in unloaded and loaded condition times (p < 0.05). Tactical deficit was then calculated, which was expressed as an absolute value percentage difference via the formula: (loaded time ¸ unloaded time x 100) – 100. Partial correlations controlling for sex analyzed relationships between relative and absolute isometric and dynamic strength (LBD and hexagonal bar deadlift, respectively), SBJ, and vertical jump height and peak power (PAPw), derived from jump height, with the tactical deficit for each of the police tasks.

Results: There were significant differences in performance between the unloaded and loaded conditions for the vertical jump (~7.53 cm lower jump height, p < 0.001, tactical deficit = 13.02 ± 6.25%), 75PR (~0.92 s slower, p = 0.03, tactical deficit = 5.11 ± 6.53%), and the 500-yard run (~12.05 s slower, p = 0.01, tactical deficit = 13.09 ± 13.20%). No significant differences were found for the BD (~0.42 s slower, p = 0.36, tactical deficit = 11.16 ± 19.06%), although the loaded performance was slower. There was a moderate negative relationship between 75PR tactical deficit with VJ height (r = -0.62, p = 0.01) and PAPw (r = -0.65, p = 0.05). For absolute LBD, there was a large negative relationship for tactical deficits with 75PR (r = -0.78, p = 0.01) and a moderate negative relationship with BD (r = -0.67, p = 0.04). For relative LBD, there was a large negative relationship with 75PR tactical deficits (r = -0.75, p = 0.01).

Conclusions: This pilot analysis showed that PPE typically decreased performance when completing police tasks. Subjects that were more powerful had a lower tactical deficit in the 75PR, which is a job task that requires explosive power for efficient execution. Greater lower-body isometric strength also appeared to mitigate the tactical deficit in the BD and 75PR. PRACTICAL APPLICATIONS: This data suggests law enforcement training staff should focus on developing lower-body strength and power to sustain the demands of PPE and decrease the tactical deficit in foot pursuit and dragging tasks.