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Potter AW, Soto LD, Friedl KE. Body composition of extreme performers in the US Marine Corps. BMJ Mil Health 2024; 170:354-358. [PMID: 36323456 PMCID: PMC11287561 DOI: 10.1136/military-2022-002189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 09/19/2022] [Indexed: 11/07/2022]
Abstract
BACKGROUND The creation of highly muscled and strong fighters is a recurring theme in human performance enhancement concepts. Physical readiness standards, intended to prevent obesity in the military, produce contradictory objectives, hounding large individuals to lose weight because of confusion between body size and body composition. Through selection, specialised training and policy exceptions the US Marine Corps has successfully developed a unique group of large (body mass index (BMI) >30 kg/m2) and strong individuals, the body bearers (BB) who carry coffins of Marines to their final resting place. METHODS We examined the relationship between adiposity and body size from nine male BB (age 25.0±2.1, height: 1.84±0.04 (1.80-1.92) m, BMI: 33.0±2.1 (30-37) kg/m2). Body composition was assessed by dual-energy X-ray absorptiometry (DXA), bioelectrical impedance (BIA) and tape measured abdominal circumference (AC)-based equations and from three-dimensional scanning (3DS). RESULTS Measures were made of fat-free mass (FFM): 90.5±7.0 (82.0-106.7) kg, where FFM included total body water: 62.8±5.0 (55.8-71.8) L, representing 69±2 (67-73) % of FFM, along with calculated FFM index: 26.8±2.4 (24.4-32.9) kg/m2). DXA measures were made for bone mineral content 4.1±0.4 (3.5-4.9) kg, bone mineral density (BMD) 1.56±0.10 (1.37-1.76) g/cm2 and %BF 19.5±6.6 (9.0-27.8). Additional measures of percent body fat (%BF) were made by AC: 20.3±2.9 (15.2-24.6), BIA: 23.7±6.4 (9.8-29.2) and 3DS: 25.5±4.7 (18.9-32.2). AC %BF reasonably matched DXA %BF, with expected overprediction and underprediction at low and high DXA %BF. BIA %BF was affected by deviations from assumed FFM hydration (72%-73%). CONCLUSION These men are classified as obese by BMI but carried massive amounts of muscle and bone on their large frames, while presenting a range of %BF irrelevant to strength performance. BMI did not predict obesity and adiposity had no association with muscle mass and strength performance.
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Affiliation(s)
- Adam W Potter
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - L D Soto
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
- Human Performance Branch, Training and Education Command, US Marine Corps, Quantico, VA, USA
| | - K E Friedl
- Office of the Senior Scientist, US Army Research Institute Environmental Medicine, Natick, Massachusetts, USA
- Neurology, University of California San Francisco, San Francisco, California, USA
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Looney DP, Potter AW, Schafer EA, Chapman CL, Friedl KE. The 300 Marines: characterizing the US Marines with perfect scores on their physical and combat fitness tests. Front Physiol 2024; 15:1406749. [PMID: 38957215 PMCID: PMC11217602 DOI: 10.3389/fphys.2024.1406749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 05/27/2024] [Indexed: 07/04/2024] Open
Abstract
Few US Marines earn perfect 300 scores on both their Physical Fitness Test (PFT) and Combat Fitness Test (CFT). The number 300 invokes the legendary 300 Spartans that fought at the Battle of Thermopylae, which inspired high physical fitness capabilities for elite ground forces ever since. Purpose Determine distinguishing characteristics of the "300 Marines" (perfect PFT and CFT scores) that may provide insights into the physical and physiological requirements associated with this capability. These tests have been refined over time to reflect physical capabilities associated with Marine Corps basic rifleman performance. Materials and methods Data were analyzed from US Marines, including 497 women (age, 29 ± 7 years; height 1.63 ± 0.07 m; body mass, 67.4 ± 8.4 kg) and 1,224 men (30 ± 8 years; 1.77 ± 0.07 m; 86.1 ± 11.1 kg). Marines were grouped by whether they earned perfect 300 scores on both the PFT and CFT (300 Marines) or not. We analyzed group differences in individual fitness test events and body composition (dual-energy x-ray absorptiometry). Results Only 2.5% (n = 43) of this sample earned perfect PFT and CFT scores (n = 21 women; n = 22 men). Compared to sex-matched peers, 300 Marines performed more pull-ups, with faster three-mile run, maneuver-under-fire, and movement-to-contact times (each p < 0.001); 300 Marines of both sexes had lower fat mass, body mass index, and percent body fat (each p < 0.001). The lower percent body fat was explained by greater lean mass (p = 0.041) but similar body mass (p = 0.085) in women, whereas men had similar lean mass (p = 0.618), but lower total body mass (p = 0.025). Conclusion Marines earning perfect PFT and CFT scores are most distinguished from their peers by their maneuverability, suggesting speed and agility capabilities. While both sexes had considerably lower percent body fat than their peers, 300 Marine women were relatively more muscular while men were lighter.
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Affiliation(s)
- David P. Looney
- United States Army Research Institute of Environmental Medicine (USARIEM), Natick, MA, United States
| | - Adam W. Potter
- United States Army Research Institute of Environmental Medicine (USARIEM), Natick, MA, United States
| | - Erica A. Schafer
- United States Army Research Institute of Environmental Medicine (USARIEM), Natick, MA, United States
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN, United States
| | - Christopher L. Chapman
- United States Army Research Institute of Environmental Medicine (USARIEM), Natick, MA, United States
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN, United States
| | - Karl E. Friedl
- United States Army Research Institute of Environmental Medicine (USARIEM), Natick, MA, United States
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Potter AW, Tharion WJ, Nindl LJ, McEttrick DM, Looney DP, Friedl KE. The normal relationship between fat and lean mass for mature (21-30 year old) physically fit men and women. Am J Hum Biol 2024; 36:e23984. [PMID: 37695262 DOI: 10.1002/ajhb.23984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/12/2023] Open
Abstract
OBJECTIVE Determine if relative body fat (%BF) remains a biological norm in physically active, non-obese American men and women and determine reference values for other components of body composition. METHODS Participants (n = 174 men, 70 women) were physically fit U.S. Marine 2nd Lieutenants, in their third decade of physical maturity (age 21-30). Body composition was assessed by dual-energy x-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA); and body images were obtained by 3D body scans. RESULTS For men and women, respectively, %BF averaged 16.2 ± 4.1 (median 15.3), 24.3 ± 4.5 (median 23.8); fat-free mass (FFM): 67.7 ± 7.2, 49.4 ± 5.3 kg; FFM index: 21.5 ± 1.8, 18.3 ± 1.6 kg/m2 ; and body mass index (BMI): 25.5 ± 1.9, 24.1 ± 2.2 kg/m2 . Bone mineral content (BMC) was 5% of FFM; total body water (TBW) was 70%-72% of FFM. Physique remained similar between median and higher percentiles of %BF. Only small changes in key measures were noted across the six-month training program. CONCLUSIONS Mean %BF of healthy active men and women in 2021 remains very similar to the 15% and 25% posited in 1980, suggesting that relative body fat has a normal fat-lean relationship in physically mature humans. These data may bring new attention to sex-appropriate %BF.
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Affiliation(s)
- Adam W Potter
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - William J Tharion
- Military Performance Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Lyndsey J Nindl
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, Tennessee, USA
| | - David M McEttrick
- Marine Expeditionary Rifle Squad, PfM Ground Combat Element Systems, Marine Corps Systems Command, Quantico, Virginia, USA
| | - David P Looney
- Military Performance Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Karl E Friedl
- Office of the Senior Scientist, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
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Cialdella-Kam L, Bloedon TK, Stone MS. Body composition as a marker of performance and health in military personnel. Front Sports Act Living 2023; 5:1223254. [PMID: 38169866 PMCID: PMC10759214 DOI: 10.3389/fspor.2023.1223254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 12/05/2023] [Indexed: 01/05/2024] Open
Abstract
Introduction Body composition standards are set to ensure operational readiness in active-duty military personnel. To meet body composition standards, some individuals, however, may engage in unhealthy weight control behaviors (i.e., weight cycling and disordered eating). The objectives of this review are to: (1) evaluate the evidence regarding body composition and the associations to physical and military specific performance; (2) discuss body composition and potential health consequences; and (3) examine the evidence of weight cycling and disordered eating behaviors in military personnel for weight control. Methods A systematic search to identify peer-reviewed research articles was conducted in PubMed on 2/20/2023 using Medical Subject Headings (MeSH) including but not limited to "Military Personnel", "Tactical Athlete", "Weight Loss", "Body Composition", and "Weight Cycling". Results A total of 225 research articles were identified. The list was narrowed down to articles from the last 20 years (2003-2023) in military personnel. Only studies in which percent body fat was directly measured were included resulting in 17 research articles for this review. Discussion Evidence-based research is limited on the relationship between body composition and operational readiness. Weight cycling and disordered eating behaviors also has been reported for weight control, yet additional research is needed. Specifically, future research should focus on female service members, racial and ethnic differences, age, and postpartum status and include other service branches (i.e., Air Force and Navy). A comprehensive survey on weight cycling, disordered eating, and weight management would be valuable to determine the prevalence and extent of this issue. This information along with performance data would guide policy makers on the relevance and appropriateness of existing body composition standards.
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Affiliation(s)
- Lynn Cialdella-Kam
- Warfighter Performance Department, Naval Health Research Center, San Diego, CA, United States
| | - Taylor K. Bloedon
- School of Applied Health, Cal Poly Humboldt, Arcata, CA, United States
| | - Michael S. Stone
- Warfighter Performance Department, Naval Health Research Center, San Diego, CA, United States
- Military and Veterans Health Solutions, Leidos, San Diego, CA, United States
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Potter AW, Looney DP, Tharion WJ, Nindl LJ, Pazmino A, Soto LD, Arcidiacono DM, Friedl KE. Physical performance and body composition reference values for modern US Marine Corps women. BMJ Nutr Prev Health 2023; 6:234-242. [PMID: 38618530 PMCID: PMC11009549 DOI: 10.1136/bmjnph-2023-000757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/13/2023] [Indexed: 04/16/2024] Open
Abstract
Women's roles in the US military have progressively changed over the past several decades. Previously women were barred from combat roles. Recent change in policy allow women into combat roles in the Marine Corps, and this has led to women being trained for combat specialties. Objectives This observational cross-sectional study describes body composition and performance values for modern Marine Corps women. Methods Volunteers were 736 Marine women who were assessed for body composition and physical performance; (age 29.5±7.3 (18-56) years; height 163.6±6.8 (131.0-186.1) cm; body mass 68.3±9.2 (42.0-105.3) kg; years in the military 8.9±6.8 (0.5-37) years-in-service). Body composition measures were obtained using dual-energy X-ray absorptiometry and single-frequency bioelectrical impedance analyses. Performance measures were obtained from official physical and combat fitness test scores (PFT; CFT) as well as from data on measured countermovement jumps (CMJ) on a calibrated force platform. Results Mean body composition metrics for Marine women were: 47.5±5.7 fat free mass (FFM) (kg), 30.1%±6.4% body fat (%BF), 2.6±0.3 bone mineral content (kg), and 25.5±2.8 body mass index (kg/m2); performance metrics included 43.4±3.2 maximal oxygen uptake (VO2max; mL.kg.min), 22.4±7.1 CMJ height (cm) and 2575±565.2 CMJ peak power (W). Data showed strong correlations (r) (≥0.70) between PFT and VO2max scores (0.75), and moderate correlations (≥0.50) between CFT and VO2max scores (0.57), CFT and PFT scores (0.60), FFM and CMJ peak power (W) (0.68), and %BF to VO2max (-0.52), PFT (-0.54), CMJ-Ht (-0.52) and CMJ relative power (W/kg) (-0.54). Conclusion Modern Marine women are both lean and physically high performing. Body composition is a poor predictor of general physical performance.
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Affiliation(s)
- Adam W Potter
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - David P Looney
- Military Performance Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - William J Tharion
- Military Performance Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Lyndsey J Nindl
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, Tennessee, USA
| | - Angie Pazmino
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Lara D Soto
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Danielle M Arcidiacono
- Military Performance Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, Tennessee, USA
| | - Karl E Friedl
- Office of the Senior Scientist, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
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Foulis SA, Friedl KE, Spiering BA, Walker LA, Guerriere KI, Pecorelli VP, Zeppetelli DJ, Reynoso MC, Taylor KM, Hughes JM. Body composition changes during 8 weeks of military training are not accurately captured by circumference-based assessments. Front Physiol 2023; 14:1183836. [PMID: 37351259 PMCID: PMC10282178 DOI: 10.3389/fphys.2023.1183836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 05/19/2023] [Indexed: 06/24/2023] Open
Abstract
In 1981, the US military adopted body fat standards to promote physical readiness and prevent obesity. Separate circumference-based equations were developed for women and men. Both predictive equations were known to underestimate %BF. However, it was not known how well these abdominal circumference-based methods tracked changes in %BF. This study examined the validity of the circumference-based %BF equations for assessing changes in %BF in young adult recruits during Army Basic Combat Training (BCT). Dual-energy X-ray absorptiometry (DXA) and circumference-based measures of %BF were obtained in women (n = 481) and men (n = 926) at the start (pre-BCT) and end (post-BCT) of 8 weeks of BCT. Repeated-measure ANOVAs were used to assess differences between DXA and circumference pre-BCT and for the change during BCT. Pre-BCT, circumferences underestimated %BF relative to DXA, with mean errors of -6.0% ± 4.4% for women and -6.0% ± 3.5% for men (both p < 0.01), and no difference between sexes was observed (p = 0.77). DXA detected a -4.0% ± 2.4% and -3.3% ± 2.8% change in %BF for women and men in response to BCT, respectively (both p < 0.01), whereas circumference estimates of %BF indicated a 0.0% ± 3.3% (p = 0.86) change in women and a -2.2% ± 3.3% (p < 0.01) change in men (sex difference by technique p < 0.01). In conclusion, circumference-based measures underestimated %BF at the start of BCT in both sexes as compared to DXA. Circumference measures underestimated changes in %BF during BCT in men and did not detect changes in women. These findings suggest that circumference-based %BF metrics may not be an appropriate tool to track changes in body composition during short duration training.
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Looney DP, Potter AW, Arcidiacono DM, Santee WR, Friedl KE. Body surface area equations for physically active men and women. Am J Hum Biol 2023; 35:e23823. [PMID: 36285812 DOI: 10.1002/ajhb.23823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/26/2022] [Accepted: 10/03/2022] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVES To improve predictive formulae for estimating body surface area (BSA) in healthy men and women using a modern three-dimensional scanner technology. METHODS Body surface areas were obtained from a convenience sample of 1267 US Marines (464 women and 803 men) using a whole body surface scanner (Size Stream SS20). The reliability of SS20 measures of total and regional BSA within participants was compared across triplicate scans. We then derived a series of formulae to estimate SS20-measured BSA using various combinations of sex, height, and mass. We also assessed relationships between percent body fat measured by dual-energy x-ray absorptiometry and sex-specific formulae errors in Marines. RESULTS Body surface areas recorded by the SS20 were highly reliable whether measured for the total body or by region (ICC ≥ .962). Formulae estimates of BSA from sex, height, and mass were precise (root-mean-square deviation, 0.031 m2 ). Errors from the Marine Corps formulae were positively associated with percent body fat for men (p = .001) but not women (p = .843). CONCLUSIONS Clinicians, military leaders, and researchers can use the newly developed BSA formulae for precise estimates in healthy physically active men and women. Users should be aware that height- and mass-based BSA estimates are less accurate for individuals with extremely low or high percent body fat.
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Affiliation(s)
- David P Looney
- Military Performance Division, United States Army Research Institute of Environmental Medicine (USARIEM), Natick, Massachusetts, USA
| | - Adam W Potter
- Thermal and Mountain Medicine Division, USARIEM, Natick, Massachusetts, USA
| | - Danielle M Arcidiacono
- Military Performance Division, United States Army Research Institute of Environmental Medicine (USARIEM), Natick, Massachusetts, USA.,Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, Tennessee, USA
| | - William R Santee
- Military Performance Division, United States Army Research Institute of Environmental Medicine (USARIEM), Natick, Massachusetts, USA
| | - Karl E Friedl
- Office of the Senior Scientist, USARIEM, Natick, Massachusetts, USA
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Potter AW, Nindl LJ, Soto LD, Pazmino A, Looney DP, Tharion WJ, Robinson-Espinosa JA, Friedl KE. High precision but systematic offset in a standing bioelectrical impedance analysis (BIA) compared with dual-energy X-ray absorptiometry (DXA). BMJ Nutr Prev Health 2022; 5:254-262. [PMID: 36619314 PMCID: PMC9813632 DOI: 10.1136/bmjnph-2022-000512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 10/03/2022] [Indexed: 11/07/2022] Open
Abstract
Bioelectrical impedance analysis (BIA) provides a practical method of body composition estimation for field research and weight management programmes, with devices and algorithms that have improved in recent years. We compared suitability of a commercial BIA system that uses multi-frequency-based proprietary algorithms (InBody 770, Cerritos, California, USA) and a laboratory-based validated single-frequency system (Quantum IV, RJL Systems, Clinton Township, Michigan, USA) with dual-energy X-ray absorptiometry (DXA) (iDXA, GE Lunar, Madison, Wisconsin, USA). Volunteers included fit non-obese active duty US Marines (480 men; 315 women), assessed by DXA and the two BIA systems. Both RJL and InBody BIA devices predicted DXA-based fat-free mass (FFM) (mean absolute error (MAE) 2.8 and 3.1 kg, respectively) and per cent body fat (%BF) (MAE 3.4% and 3.9%, respectively), with higher correlations from the InBody device (r2=0.96 (%BF) and 0.84 (FFM)) versus the RJL (r2=0.92 (%BF) and 0.72 (FFM)). InBody overpredicted FFM (bias +2.7, MAE 3.1 kg) and underpredicted %BF (bias -3.4 and MAE 3.9%) versus the RJL. A 3% correction factor applied to the InBody device results provided values very close to the DXA measurements. These findings support the application of modern BIA systems to body composition goals of maximum %BF and minimum lean body mass for both men and women.
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Affiliation(s)
- Adam W Potter
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Lyndsey J Nindl
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Lara D Soto
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Angie Pazmino
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - David P Looney
- Military Performance Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - William J Tharion
- Military Performance Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Jasmine A Robinson-Espinosa
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Karl E Friedl
- Office of the Senior Scientist, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
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