Only the strong survive: Relationships between lower-body strength and power with the 75-kg and 91-kg body drag

Abstract

INTRODUCTION: One of the critical job tasks identified for law enforcement fficers is the ability to rescue a person in immediate danger. For this reason, some law enforcement agencies (LEA) administer a body drag (BD) as part of their state-mandated Work Sample Test battery (WSTB). The BD is one of five events in the WSTB, and recruits must pass this test to graduate training academy. However, the dummy used for this test weighs 75 kg while the average US adult male currently weighs ~91 kg. Before agencies can update their standards, research is needed to determine the physical characteristics required to successfully perform the BD with lighter and heavier masses. PURPOSE: To examine how lower-body strength and power correlate to dragging a 75-kg and 91-kg dummy. METHODS: Thirty (19 male, 11 female) college-aged students were recruited for this study. Subjects were age-matched to a typical law enforcement recruit cohort. Testing occurred over three days; day 1 included anthropometrics, standing broad jump (SBJ), vertical jump (VJ), and a 1RM hexagonal bar deadlift (HBDL). Relative SBJ was calculated from SBJ scores (RSBJ), peak anaerobic powermeasured in watts (PAPw) was calculated from VJ and body mass, relative power was calculated by dividing the PAPw value by the participants body mass. Relative strength was calculated by dividing the HBDL by the participant’s body mass (RHDBL). A counterbalanced approach was used for days 2 and 3 which consisted of dragging a 75-kg dummy or a 91-kg dummy 9.75 m. The BDwas performed according to the LEA standards. Subjects squatted down and put their arms under the dummy’s arms and across its chest. The subject then lifted the dummy and stood in an upright position and started backpedaling towards the finish line. Timing started once the dummy’s feet crossed the start line and ended when the feet crossed the finish line. Velocity was calculated bydividing 9.75 m by the BD time. Partial correlations controlling for sex calculated the relationship between the performance measures and the BD velocities. RESULTS: Table 1 displays the partial correlations data. HBDL and PAPw were significantly correlated with performance on both dummy masses. SBJ and VJ were only correlated with performance in the 75-kg dummy. Body mass alsocorrelated with 91 kg BD velocity. CONCLUSIONS: Controlling for sex, absolute strength (HDBL) and absolute power (PAPw) were important physical qualities for BD performance regardless of the dummy mass. Combined with the findings that the relative measures were not significant for both masses, these results suggest that the heavier dummy mass requires a specific amount of absolute strength and power to successfully move. PRACTICAL APPLICATIONS: LEA staff, should they upgrade their BD testing to heavier dummies or wish to develop the physical capability of dragging a heavier mass, should emphasize maximal lower-body strength and power training to ensure successful task performance.<br/