The impact of external loads carried by police officers on vertical jump performance

Abstract

INTRODUCTIONPolice officers require a high level of lower limb power to complete occupational tasks. Deficits inlower limb power have been linked to an increased risk of injury in this population. With the additionof around 10 kg of external loads that police officers are required to carry, it is thought that theability to perform explosive, power-based movements may be impacted. The purpose of this studywas to examine the impact that external loads carried by police officers had on their vertical jump(VJ) height and peak anaerobic power output (PAPw).METHODSRetrospective data of 47 (mean age = 38.79 ± 7.97 years) police officers from a US Law EnforcementAgency (LEA) were used for analysis. Officers completed a VJ dressed either in gym clothing or in fullduty attire and occupational loads (9.57 ± 0.94 kg, range 7.08 – 12.02 kg). VJ heights and body masswere used in the Sayers Peak Power Equation to calculate PAPw. Power-to-weight (P:W) ratios werethen calculated by dividing PAPw by the officer’s body mass. Paired samples t-tests were used toinvestigate differences in performance with alpha levels set at 0.05 a priori.RESULTSWhile VJ height significantly (p < 0.001) decreased with load (unloaded height =49.49 ± 8.46 cm:loaded height =43.62 ± 7.68 cm), PAPw increased significantly (p < 0.01) (unloaded = 4963.02 ±879.17: loaded = 5039.83 ± 913.92 watts). A Pearson’s correlation showed a significant (p < 0.01)low-moderate (r = 0.387) relationship between absolute load (9.57 ± .94 kg) and change in PAPw,and a significant (p < 0.01) strong (r = 0.794) correlation between relative load and changes in P:W.CONCLUSIONSThis study supports previous research that suggests that occupational load carriage has a negativeimpact on VJ performance in police officers and may be detrimental to job performance. Targetedtraining programs aimed at increasing lower limb power may mitigate these negative effects