Revisiting the United States Army body composition standards: a receiver operating characteristic analysis

Mobile phone applications for 3-dimensional scanning and digital anthropometry: a precision comparison with traditional scanners

BACKGROUND

The precision of digital anthropometry through 3-dimensional (3D) scanning has been established for relatively large, expensive, non-portable systems. The comparative performance of modern mobile applications is unclear.

SUBJECTS/METHODS

Forty-six adults (age: 23.3 ± 5.3 y; BMI: 24.4 ± 4.1 kg/m2) were assessed in duplicate using: (1) a mobile phone application capturing two individual 2D images, (2) a mobile phone application capturing serial images collected during a subject's complete rotation, (3) a traditional scanner with a time of flight infrared sensor collecting visual data from a subject being rotated on a mechanical turntable, and (4) a commercial measuring booth with structured light technology using 20 infrared depth sensors positioned in the booth. The absolute and relative technical error of measurement (TEM) and intraclass correlation coefficient (ICC) for each method were established.

RESULTS

Averaged across circumferences, the absolute TEM, relative TEM, and ICC were (1) 0.9 cm, 1.5%, and 0.975; (2) 0.5 cm, 0.9%, and 0.986; (3) 0.8 cm, 1.5%, and 0.974; and (4) 0.6 cm, 1.1%, and 0.985. For total body volume, these values were (1) 2.2 L, 3.0%, and 0.978; (2) 0.8 L, 1.1%, and 0.997; (3) 0.7 L, 0.9%, and 0.998; and (4) 0.8 L, 1.1%, and 0.996, with segmental volumes demonstrating higher relative errors.

CONCLUSION

A 3D scanning mobile phone application involving full rotation of subjects in front of a smartphone camera exhibited similar reliability to larger, less portable, more expensive 3D scanners. In contrast, larger errors were observed for a mobile scanning application utilizing two 2D images, although the technical errors were acceptable for some applications.

Relationships Between Anthropometric Measures and Body Composition With Individual ACFT Event Performance Among Army Reserve Officers' Training Corps Cadets

ABSTRACT

Thompson, MB, Lawson, DJ, Orr, RM, Lockie, RG, and Dawes, JJ. Relationships between anthropometric measures and body composition with individual ACFT event performance among army reserve officers' training corps cadets. J Strength Cond Res 38(4): 749-754, 2024-The U.S. military commonly uses body composition as an indicator of a soldier's potential to meet the physical demands required of their occupation. The purpose of this study was to determine whether significant relationships existed between select body composition variables and Army Combat Fitness Test (ACFT) performance among a cohort of university Army Reserve Officers' Training Corps (ROTC) cadets. Twenty-six male (20.4 ± 1.6 years, 81.8 ± 8.5 kg, 178.3 ± 7.8 cm) and 12 female (19.9 ± 1.4 years, 64.2 ± 6.7 kg, 161.9 ± 4.9 cm) cadets voluntarily participated in this study. Body composition was measured using bioelectrical impedance analysis, and ACFT event scores were recorded by the cadre using the U.S. Army standard protocol and provided to the investigators. Pearson's correlations were used to identify relationships between body composition variables and ACFT event performance with an alpha level of p ≤ 0.05. Moderate to strong relationships were observed between total body water, dry lean mass, lean body mass, skeletal muscle mass, body fat mass (FM), and body fat percentage and all event scores for the sample as a whole. Body mass index showed weak to moderate significant positive relationships with hand-release push-up and maximum hexagonal bar deadlift in the sample as a whole. No relationships were observed in the men of this sample. All body composition variables showed moderate, nonsignificant relationships with at least 1 ACFT event within the women of this sample. Considering the findings of this study, a multitude of variables could be useful to assess ROTC cadets as predictors for ACFT performance. Reserve Officers' Training Corps programs should emphasize attaining and maintaining functional lean mass, whereas reducing nonfunctional body mass (i.e., excess FM) among cadets to enhance health and performance across the occupational life span.

Body shape and performance on the US Army Combat Fitness Test: Insights from a 3D body image scanner

OBJECTIVE

To identify relationships between body shape, body composition, sex and performance on the new US Army Combat Fitness Test (ACFT).

METHODS

Two hundred and thirty-nine United States Military Academy cadets took the ACFT between February and April of 2021. The cadets were imaged with a Styku 3D scanner that measured circumferences at 20 locations on the body. A correlation analysis was conducted between body site measurements and ACFT event performance and evaluated using Pearson correlation coefficients and p-values. A k-means cluster analysis was performed over the circumference data and ACFT performance were evaluated between clusters using t-tests with a Holm-Bonferroni correction.

RESULTS

The cluster analysis resulted in 5 groups: 1. "V" shaped males, 2. larger males, 3. inverted "V" shaped males and females, 4. "V" shaped smaller males and females, and 5. smallest males and females. ACFT performance was the highest in Clusters 1 and 2 on all events except the 2-mile run. Clusters 3 and 4 had no statistically significant differences in performance but both clusters performed better than Cluster 5.

CONCLUSIONS

The association between ACFT performance and body shape is more detailed and informative than considering performance solely by sex (males and females). These associations may provide novel ways to design training programs from baseline shape measurements.

Effects of a period without mandatory physical training on maximum oxygen uptake and anthropometric parameters in naval cadets

The effects of a period without physical training on the civilian population are well established. However, no studies show the effects of a period without mandatory physical training on maximum oxygen uptake (VO₂ max) and anthropometric parameters in naval cadets. This study aimed to investigate changes in VO₂ max and anthropometric parameters after 12 weeks without mandatory physical training in naval cadets. The sample was 38 healthy and physically active naval cadets. The measured variables, including VO₂ max and anthropometric parameters, were evaluated through the 12-minute race test (12MRT) and the somatotype. Both variables had a separation of 12 weeks without mandatory physical training. A t-test for related samples was used to evidence changes between the test and post-test; effect size was calculated through Cohen’s d-test. Distance in 12MRT and VO₂ max showed significant decreases at the end of 12 weeks without mandatory physical training (p < 0.001). Likewise, the tricipital skinfold thickness and the endomorphic component showed significant increases (p < 0.05). 12 weeks without mandatory physical training significantly reduces the VO₂ max in naval cadets. Simultaneously, the same period without physical training increases both the tricipital skinfold thickness and the endomorphic component in this population.

Regular strength training and baseline fitness in overweight infantry members of Slovenian Armed Forces

INTRODUCTION

The prevalence of overweight subjects in military cohorts increases despite the obligatory army physical fitness test (APFT) requirements and the negative consequences of possible test failure due to the increased body mass index (BMI). Studies that have examined the association of BMI with baseline fitness in the military are showing conflicting evidence. The primary aim of the study is to examine BMI effects on baseline fitness that was measured by APFT and additional functional performance tests (FT) (vertical countermovement jump with and without load, loaded prone plank, single-leg hamstring bridge test and pull-ups). Our secondary goal is to explore if regular strength training modifies the BMI effect on baseline fitness.

METHODS

A cross-sectional study on a sample of 118 male infantry soldiers that have performed APFT and FT was carried out. Body mass and body height measurements were used to calculate BMI, and to categorise participants into BMI ranks. Two independent categorical variables (BMI rank and strength training) were used to evaluate their influence on dependent variables of physical performance acquired from APFT and FT.

RESULTS

A significantly large size effect of BMI rank (F=1.69, p=0.037; effect size (ES)=0.15) and regular strength training (F=2.66, p=0.006; ES=0.21) on physical performance was found. It was shown that strength training had a medium ES on push-up and pull-up performance, as well as on the overall APFT score and loaded plank.

CONCLUSIONS

The importance of regular strength training and normal BMI for better overall baseline fitness in infantry members was highlighted. Most importantly, it was shown that performance is not affected in overweight soldiers who are performing regular strength training in addition to their daily physical training.

TRIAL REGISTRATION NUMBER

NCT03415464.

Comparison of Anthropometric Measures in US Military Personnel in the Classification of Overweight and Obesity

OBJECTIVE

This study aimed to determine (1) the level of agreement between BMI, circumference-based equation (CBE) measures, waist circumference (WC), and bioelectrical impedance analysis (BIA) measures and (2) whether BMI, CBE measures, or WC alone or in combination adequately reflects adiposity in military personnel compared with BIA.

METHODS

BMI from measured height and weight (using military overweight cutoffs in men [BMI ≥ 27.5 kg/m² ] and World Health Organization overweight cutoffs [BMI ≥ 25.0 kg/m² ]), BMI body fat percentage (BF%), WC, CBE BF%, and BIA BF% were collected. Respondents (N = 389, 78% men) were categorized with normal fat versus overweight, obesity, or overfat. Levels of agreement and standard screening performance measures were compared between anthropometric measures and BIA.

RESULTS

World Health Organization BMI and BIA BF% classified the most men and women with overweight/obesity; WC with BMI (BMI + WC) and WC alone classified the fewest men and women with overweight/obesity. Levels of agreement were all statistically significant and highest for BMI (men: Cohen's κ = 0.711; women: Cohen's κ = 0.814) and lowest for WC and BMI + WC (all Cohen's κ ≤ 0.270). BMI + CBE performed best overall (sensitivity = 50.9%, false discovery rate = 5.4%).

CONCLUSIONS

Our findings support BMI + CBE as an easy-to-implement combination to assess adiposity in the military.