Association of anthropometric characteristics of law enforcement officers with perceived ratings of fit, comfort, and pain in the use of body armor

Knowledge gaps exist on association between law enforcement officer (LEO) anthropometric characteristics and perceived body armour fit, armour discomfort, and armour-caused pain. This study assessed the correlation and identified influential torso dimensions for armour sizing and design applications. Nine-hundreds and seventy-four LEOs across the U.S. participated in a national study on LEO armour use and body dimensions. Perceived ratings of armour fit, armour discomfort, and body pain were found moderately correlated with each other. In addition, armour fit ratings were associated with certain torso anthropometric characteristics, such as chest circumference, chest breadth, chest depth, waist circumference, waist breadth (sitting), waist front length (sitting), body weight, and body mass index. LEOs who reported armour poor fit, armour discomfort, and armour-caused pain had a larger mean of body dimensions than the "armor good fit" group. More women than men had poor fit, discomfort, and body pain in the use of body armour.Practitioner summary: The identified influential body measurements can be used as the "drivers" for multivariate analyses to develop an improved armour sizing system to further LEO protection. The study also suggests consideration of gender specific armour sizing systems to accommodate differences in torso configurations between male and female officers and to resolve the concern that more female officers had poor armour fit than male officers.

Needs and Procedures for a National Anthropometry Study of Law Enforcement Officers

OBJECTIVES

This research aims to determine the need and extent for a national anthropometry survey of law enforcement officers (LEOs) via an exploratory investigation of anthropometric changes of LEOs in four decades and comparisons of the LEO data with three existing military and civilian anthropometry sources.

BACKGROUND

The best available anthropometric dataset of LEOs is 45 years old and has largely become outdated due to demographic changes. Assessing the extent of anthropometric changes of LEOs through a sample and evaluating the differences of the sample against existing anthropometric datasets is a step toward ascertaining the necessity for a national LEO anthropometry study.

METHOD

Thirty-two body dimensions of 67 regional male LEOs and seven female LEOs were measured, and the data of males were compared with the best available LEO anthropometry data from 1975 and three recent non-LEO anthropometry databases.

RESULTS

Anthropometric dimensions were significantly different between this LEO study and existing data sources, especially in chest circumference and body weight. Most of the significant differences are important differences for LEO protective gear and vehicle design.

CONCLUSION

The study confirmed that the existing 45-year-old LEO dataset and recent Army and civilian datasets would not be suitable for armor and equipment design for the current LEO population.

APPLICATION

The study results are useful in supporting the decision of investing in a national LEO anthropometry survey and for equipment manufacturers to recognize the distinctiveness of LEO anthropometry from other populations and the magnitude of anthropometry changes of LEOs over the past 45 years.

Comparison of Heart Rate Monitoring Accuracy between Chest Strap and Vest during Physical Training and Implications on Training Decisions

Heart rate (HR) and heart rate variability (HRV) based physiological metrics such as Excess Post-exercise Oxygen Consumption (EPOC), Energy Expenditure (EE), and Training Impulse (TRIMP) are widely utilized in coaching to monitor and optimize an athlete’s training load. Chest straps, and recently also dry electrodes integrated to special sports vests, are used to monitor HR during sports. Mechanical design, placement of electrodes, and ergonomics of the sensor affect the measured signal quality and artefacts. To evaluate the impact of the sensor mechanical design on the accuracy of the HR/HRV and further on to estimation of EPOC, EE, and TRIMP, we recorded HR and HRV from a chest strap and a vest with the same ECG sensor during supervised exercise protocol. A 3-lead clinical Holter ECG was used as a reference. Twenty-five healthy subjects (six females) participated. Mean absolute percentage error (MAPE) for HR was 0.76% with chest strap and 3.32% with vest. MAPE was 1.70% vs. 6.73% for EE, 0.38% vs. 8.99% for TRIMP and 3.90% vs. 54.15% for EPOC with chest strap and vest, respectively. Results suggest superior accuracy of chest strap over vest for HR and physiological metrics monitoring during sports.

Clothing adjustments for concealed soft body armor during moderate physical exertion

Previous research has studied the impact of Level II concealed soft body armor (SBA) on the augmentation of heat storage in a hot environment simulating a typical summer day in the southeastern United States (wet bulb globe temperature [WBGT] = 30°C) and noted a significant difference between macro- and micro-WBGTs. The purpose of this study was to characterize the microclimate (micro-WBGT) under a concealed Level II SBA during 60 min of moderately intense work at two separate macro-WBGTs (26°C and 30°C), and to establish WBGT corrections to allow prediction of heat strain in an individual wearing a concealed Level II SBA. A single trial was performed with nine volunteers (27 ± 4 years) outfitted with a simulated standard law enforcement uniform and a traditional concealed Level II SBA, in a moderately warm environment (WBGT = 26°C). Each participant performed cycles of 12 min of walking (1.25 L · min(-1)) and 3 min of arm curls (14.3 kg, 0.6 L · min(-1)) with a 5 min rest after every other cycle, for a total of 60 minutes. This trial was compared to an identical previously completed 60-min work bout at 30°C. A two-way repeated measures ANOVA with Post hoc Bonferroni and paired samples t-test analysis was conducted. A greater difference between macro- micro-WBGTs existed at 26°C compared to the 30°C macro-WBGT. Under these conditions, a moderate work in Level II SBA requires a WBGT correction of 8.9°C and 6.2°C at macro-WBGTs of 26°C and 30°C, respectively. A modified simple linear regression prediction model was established for mean Micro-WBGT for each macro-WBGTs after the plateau point at the 30 min mark. The derivation regressions at 26°C (R(2) = 0.99), and 30°C (R(2) = 0.99) indicate that micro-WBGT could be predicted for each 15 minutes time at both macro-WBGTs tested for individuals doing moderate intensity (300 Kcals · hr(-1)) work wearing concealed Level II SBA.