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Gifford RM, Taylor N, Carroll A, Sweeting J, Parsons IT, Stacey MJ, Homer NZM, Tsanas A, Woods DR, Reynolds RM. Assessment of salivary cortisol dynamics in an infantry training exercise: a pilot study. BMJ Mil Health 2024:e002622. [PMID: 38604756 DOI: 10.1136/military-2023-002622] [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: 11/08/2023] [Accepted: 02/26/2024] [Indexed: 04/13/2024]
Abstract
INTRODUCTION Measuring cortisol during military training offers insights into physiological responses to stress. We attempted precisely timed, cortisol awakening response (CAR) and pre-sleep cortisol (PSC), and diurnal slope (peak morning minus evening cortisol), during a British Army exercise. We aimed to understand cortisol dynamics and evaluate the feasibility of CAR and PSC in this environment. METHOD Setting: high-intensity, 10-day infantry exercise. Participants: regular infantry soldiers exercising (EX, n=25) or headquarters-based (HQ, n=6). Participants undertook PSC and WAKE and WAKE+30 min samples after 1-2 days, 5-6 days and 9-10 days. Wrist-worn GENEActiv accelerometers were used to assess sleep duration in EX only. Samples taken ±15 min from prespecified time points were deemed adherent. Validated questionnaires were used to measure resilience and perceived stress. Cortisol and cortisone were measured simultaneously by liquid chromatography tandem mass spectrometry. RESULTS From adherent participants' samples, CAR was positive and tended to decrease as the exercise progressed. From all available data, HQ demonstrated greater diurnal slope than EX (F=7.68, p=0.02), reflecting higher morning cortisol (F=4.72, p=0.038) and lower PSC (p=0.04). No differences were seen in cortisol:cortisone ratio. 26.1% of CAR samples were adherent, with moderately strong associations between adherence and stress (r=0.41, p=0.009) but no association between adherence and day of exercise (χ2=0.27, p=0.8), sleep duration (r=-0.112, p=0.43) or resilience (r=-0.79, p=0.75). Test-retest reliability ratings for CAR were Cronbach's α of 0.48, -11.7 and 0.34 for the beginning, middle and end of the exercise, respectively. CONCLUSIONS We observed a reduction in morning cortisol and decreased diurnal slope during a high-intensity military exercise, compared with the HQ comparator cohort in whom diurnal slope was preserved. A carefully timed CAR was not feasible in this setting.
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Affiliation(s)
- Robert M Gifford
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - N Taylor
- Academic Department of Military General Practice, Royal Centre for Defence Medicine, Birmingham, UK
| | - A Carroll
- Royal Centre for Defence Medicine, Birmingham, UK
| | - J Sweeting
- Royal Centre for Defence Medicine, Birmingham, UK
| | - I T Parsons
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - M J Stacey
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - N Z M Homer
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - A Tsanas
- Usher Institute, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - D R Woods
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - R M Reynolds
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
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O'Leary TJ, Gifford RM, Knight RL, Wright J, Handford S, Venables MC, Reynolds RM, Woods D, Wardle SL, Greeves JP. Sex differences in energy balance, body composition, and metabolic and endocrine markers during prolonged arduous military training. J Appl Physiol (1985) 2024; 136:938-948. [PMID: 38385180 DOI: 10.1152/japplphysiol.00864.2023] [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: 12/01/2023] [Revised: 02/20/2024] [Accepted: 02/20/2024] [Indexed: 02/23/2024] Open
Abstract
This study investigated sex differences in energy balance, body composition, and metabolic and endocrine markers during prolonged military training. Twenty-three trainees (14 women) completed 44-wk military training (three terms of 14 wk with 2-wk adventurous training). Dietary intake and total energy expenditure were measured over 10 days during each term by weighed food and doubly labeled water. Body composition was measured by dual-energy X-ray absorptiometry (DXA) at baseline and at the end of each term. Circulating metabolic and endocrine markers were measured at baseline and at the end of terms 2 and 3. Absolute energy intake and total energy expenditure were higher, and energy balance was lower, for men than women (P ≤ 0.008). Absolute energy intake and balance were lower, and total energy expenditure was higher, during term 2 than terms 1 and 3 (P < 0.001). Lean mass did not change with training (P = 0.081). Fat mass and body fat increased from term 1 to terms 2 and 3 (P ≤ 0.045). Leptin increased from baseline to terms 2 and 3 in women (P ≤ 0.002) but not in men (P ≥ 0.251). Testosterone and free androgen index increased from baseline to term 3 (P ≤ 0.018). Free thyroxine (T4) decreased and thyroid-stimulating hormone (TSH) increased from baseline to term 2 and term 3 (P ≤ 0.031). Cortisol decreased from baseline to term 3 (P = 0.030). IGF-I and total triiodothyronine (T3) did not change with training (P ≥ 0.148). Men experienced greater energy deficits than women during military training due to higher total energy expenditure.NEW & NOTEWORTHY Energy deficits are common in military training and can result in endocrine and metabolic disturbances. This study provides first investigation of sex differences in energy balance, body composition, and endocrine and metabolic markers in response to prolonged and arduous military training. Men experienced greater energy deficits than women due to higher energy expenditure, which was not compensated for by increased energy intake. These energy deficits were not associated with decreases in fat or lean mass or metabolic or endocrine function.
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Affiliation(s)
- Thomas J O'Leary
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
- Division of Surgery and Interventional Science, UCL, London, United Kingdom
| | - Robert M Gifford
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Rebecca L Knight
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
| | - Jennifer Wright
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
| | - Sally Handford
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
| | - Michelle C Venables
- Medical Research Council, Elsie Widdowson Laboratory, Cambridge, United Kingdom
| | - Rebecca M Reynolds
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - David Woods
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
- Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, United Kingdom
| | - Sophie L Wardle
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
- Division of Surgery and Interventional Science, UCL, London, United Kingdom
| | - Julie P Greeves
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
- Division of Surgery and Interventional Science, UCL, London, United Kingdom
- Norwich Medical School, University of East Anglia, Norwich, United Kingdom
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O'Leary TJ, Izard RM, Tang JCY, Fraser WD, Greeves JP. Hormonal contraceptive use is associated with altered bone structural and metabolic responses to military training in women: An observational cohort study. Bone 2024; 181:117012. [PMID: 38216077 DOI: 10.1016/j.bone.2024.117012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/19/2023] [Accepted: 01/05/2024] [Indexed: 01/14/2024]
Abstract
Military training increases tibial density and size. Female sex hormones may influence the adaption of bone to loading, but it is unknown if women using different hormonal contraceptives adapt similarly to military training. One hundred and sixteen women (57 women not using hormonal contraceptives [non-users], 38 combined oral contraceptive pill [COCP] users, 21 depot medroxyprogesterone acetate [DMPA] users) completed this study. Tibial volumetric bone mineral density (vBMD) and geometry were measured by peripheral quantitative computed tomography (4 %, 14 %, 38 %, and 66 % sites) at the start (week 1) and end (week 14) of British Army basic training. Circulating markers of bone and calcium metabolism were measured at weeks 1, 2, 4, 6, 10, and 14. Training increased trabecular vBMD at the 4 % site, periosteal perimeter at the 14 % and 66 % sites, and total area, cortical area, cortical thickness, and bone strength at all sites (0.1 to 1.6 %, p ≤ 0.009), with no differences between hormonal contraceptive groups (p ≥ 0.127). Trabecular vBMD increased at the 14 % site in non-users (0.8 %, p = 0.005), but not in COCP or DMPA users (p ≥ 0.205). Periosteal perimeter increased at the 38 % site in COCP (0.4 %, p < 0.001) and DMPA (0.5 %, p < 0.001) users, but not in non-users (p = 0.058). Training had no effect on periosteal perimeter at the 4 % site or cortical vBMD or endosteal perimeter at any site (p ≥ 0.168). βCTX decreased and PINP increased during training with no difference between hormonal contraceptive groups. Training increased iPTH in non-users, but not COCP or DMPA users. Hormonal contraceptives may exert site-specific effects on the mechanobiology of bone, with higher endogenous oestradiol promoting trabecularisation and inhibiting periosteal expansion in non-users compared with hormonal contraceptive users.
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Affiliation(s)
- Thomas J O'Leary
- Army Health and Performance Research, Army HQ, Andover, UK; Division of Surgery and Interventional Science, UCL, London, UK
| | | | - Jonathan C Y Tang
- Bioanalytical Facility, Norwich Medical School, University of East Anglia, Norwich, UK; Clinical Biochemistry, Departments of Laboratory Medicine and Departments of Diabetes and Endocrinology, Norfolk and Norwich University Hospital, Norwich, UK
| | - William D Fraser
- Bioanalytical Facility, Norwich Medical School, University of East Anglia, Norwich, UK; Clinical Biochemistry, Departments of Laboratory Medicine and Departments of Diabetes and Endocrinology, Norfolk and Norwich University Hospital, Norwich, UK
| | - Julie P Greeves
- Army Health and Performance Research, Army HQ, Andover, UK; Division of Surgery and Interventional Science, UCL, London, UK; Bioanalytical Facility, Norwich Medical School, University of East Anglia, Norwich, UK.
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Scheffer JH, Dunshea-Mooij CAE, Armstrong S, MacManus C, Kilding AE. Prevalence of low energy availability in 25 New Zealand elite female rowers - A cross sectional study. J Sci Med Sport 2023; 26:640-645. [PMID: 37802760 DOI: 10.1016/j.jsams.2023.09.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/14/2023] [Accepted: 09/19/2023] [Indexed: 10/08/2023]
Abstract
OBJECTIVES To quantify energy availability (EA) in elite female rowers, determine its association with bone mineral density (BMD), and examine the ability of the low energy availability in females-questionnaire (LEAF-Q) and brief eating disorder in athletes-questionnaire (BEDA-Q) to distinguish between low and normal EA. DESIGN Observational cross-sectional study. METHODS Twenty-five elite female rowers participated in the study. EA was calculated by means of a 4-day food intake diary and analysis of training load. Low energy availability (LEA) was defined as EA <30 kCal * kg-1 * FFM-1 * day-1. Dual-energy X-ray absorptiometry (DXA) was used to assess fat free mass (FFM) and BMD Z-scores. LEA risk was assessed using the LEAF-Q and BEDA-Q. RESULTS The mean EA was 23.2 ± 12.2 kCal * kg-1 * FFM-1 * day-1. Prevalence of LEA was 64 %. The mean BMD Z-score was 1.6 ± 0.6 (range: 0.7 to 2.9). Athletes with LEA had a significantly higher BEDA-Q score than the group with normal EA (mean 0.30 ± 0.17 vs. 0.09 ± 0.11, P < 0.05), but LEAF-Q score was not different between groups (mean 10.4 ± 4.6, 8.2 ± 4.5, P = 0.29). CONCLUSION Low energy availability is common amongst elite female rowers in New Zealand and is positively correlated with higher scores on the BEDA-Q. Bone mineral density was normal irrespective of EA status.
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Affiliation(s)
| | | | - Stuart Armstrong
- Rowing New Zealand/High Performance Sport New Zealand, New Zealand
| | | | - Andrew E Kilding
- Sport Performance Research Institute New Zealand, School of Sport and Recreation, Auckland University of Technology/High Performance Sport New Zealand, New Zealand
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Taylor N, Carroll A, Gifford RM. Five-day evaluation of the acceptability and comfort of wearable technology at four anatomical locations during military training. BMJ Mil Health 2023:e002524. [PMID: 38053268 DOI: 10.1136/military-2023-002524] [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: 07/25/2023] [Accepted: 11/10/2023] [Indexed: 12/07/2023]
Abstract
INTRODUCTION Wearable sensor technologies enable Defence to optimise human performance, remotely identify physiological abnormalities and enhance medical support. Maximising the acceptability of devices will ensure they are worn alongside other equipment. This study assessed the acceptability and comfort of four devices at different anatomical locations during military training. METHOD A cross-sectional pilot study during a live firing infantry exercise or adventurous training assessed four anatomical locations concurrently over 5 days: finger, wrist, upper arm and chest. Participants rated comfort, acceptability and preference using a standardised questionnaire after 12 hours and 5 days of wear. RESULTS Twenty-one regular British Army personnel soldiers participated, aged 24.4 (4.3) years. The upper arm location received the highest rating by participants for comfort, followed in order by wrist, finger and chest (p=0.002, Χ2=40.0). The finger was most commonly identified as uncomfortable during specific activities (76%), followed by chest (48%), wrist (23%) and upper arm devices (14%). There was no significant difference in participant confidence in the devices to collect data or allow movement, but there was a trend towards greater confidence in upper arm and wrist locations to stay in position than the others (p=0.059, Χ2=28.0). After 5 days of wear, 43% of participants said they preferred the upper arm for comfort, followed by wrist (36%), finger (24%) and chest (10%). 73% and 71% would wear the wrist and upper arm devices on deployed operations, compared with 29% and 24% for chest and finger devices, respectively. CONCLUSION The upper arm location offered greater acceptability and comfort than finger, wrist or chest locations. It is essential to consider such findings from occupationally relevant settings when selecting wearable technology. A larger service evaluation in diverse settings is recommended to guide the choice of the most acceptable wearable devices across different equipment, roles and environments.
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Affiliation(s)
- Natalie Taylor
- Academic Department of Military General Practice, Royal Centre for Defence Medicine, Birmingham, UK
| | - A Carroll
- Royal Centre for Defence Medicine, Birmingham, UK
| | - R M Gifford
- Academic Department Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
- British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
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Sekel NM, Hughes JM, Sterczala AJ, Mroz KH, Lovalekar M, Cauley J, Greeves JP, Nindl BC. Utility of HR-pQCT in detecting training-induced changes in healthy adult bone morphology and microstructure. Front Physiol 2023; 14:1266292. [PMID: 37929211 PMCID: PMC10623356 DOI: 10.3389/fphys.2023.1266292] [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: 08/02/2023] [Accepted: 10/03/2023] [Indexed: 11/07/2023] Open
Abstract
Healthy bone adjusts its traits in an exceptionally coordinated, compensatory process. Recent advancements in skeletal imaging via High-Resolution Peripheral Quantitative Computed Tomography (HR-pQCT) allows for the in vivo 3-dimensional and longitudinal quantification of bone density, microarchitecture, geometry, and parameters of mechanical strength in response to varying strain stimuli including those resulting from exercise or military training. Further, the voxel size of 61 microns has the potential to capture subtle changes in human bone in as little as 8 weeks. Given the typical time course of bone remodeling, short-term detection of skeletal changes in bone microstructure and morphology is indicative of adaptive bone formation, the deposition of new bone formation, uncoupled from prior resorption, that can occur at mechanistically advantageous regions. This review aims to synthesize existing training-induced HR-pQCT data in three distinct populations of healthy adults excluding disease states, pharmacological intervention and nutritional supplementation. Those included are: 1) military basic or officer training 2) general population and 3) non-osteoporotic aging. This review aims to further identify similarities and contrasts with prior modalities and cumulatively interpret results within the scope of bone functional adaptation.
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Affiliation(s)
- Nicole M. Sekel
- Neuromuscular Research Laboratory, Warrior Human Performance Research Center, University of Pittsburgh, Pittsburgh, PA, United States
| | - Julie M. Hughes
- Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, MA, United States
| | - Adam J. Sterczala
- Neuromuscular Research Laboratory, Warrior Human Performance Research Center, University of Pittsburgh, Pittsburgh, PA, United States
| | - Kelly H. Mroz
- Neuromuscular Research Laboratory, Warrior Human Performance Research Center, University of Pittsburgh, Pittsburgh, PA, United States
| | - Mita Lovalekar
- Neuromuscular Research Laboratory, Warrior Human Performance Research Center, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jane Cauley
- Department of Epidemiology, School of Public Health, University of Pittsburgh, Pittsburgh, PA, United States
| | - Julie P. Greeves
- Army Health and Performance Research, UK Army, Andover, United Kingdom
| | - Bradley C. Nindl
- Neuromuscular Research Laboratory, Warrior Human Performance Research Center, University of Pittsburgh, Pittsburgh, PA, United States
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Dyches KD, Friedl KE, Greeves JP, Keller MF, McClung HL, McGurk MS, Popp KL, Teyhen DS. Physiology of Health and Performance: Enabling Success of Women in Combat Arms Roles. Mil Med 2023; 188:19-31. [PMID: 37490562 DOI: 10.1093/milmed/usac256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 02/28/2022] [Accepted: 08/16/2022] [Indexed: 07/27/2023] Open
Abstract
INTRODUCTION The modern female soldier has yet to be fully characterized as she steps up to fill new combat roles that have only recently been opened to women. Both U.S. and U.K. military operational research efforts are supporting a science-based evolution of physical training and standards for female warfighters. The increasing representation of women in all military occupations makes it possible to discover and document the limits of female physiological performance. METHOD An informal Delphi process was used to synthesize an integrated concept of current military female physiological research priorities and emerging findings using a panel of subject matter experts who presented their research and perspectives during the second Women in Combat Summit hosted by the TriService Nursing Research Program in February 2021. RESULTS The physical characteristics of the modern soldier are changing as women train for nontraditional military roles, and they are emerging as stronger and leaner. Capabilities and physique will likely continue to evolve in response to new Army standards and training programs designed around science-based sex-neutral requirements. Strong bones may be a feature of the female pioneers who successfully complete training and secure roles traditionally reserved for men. Injury risk can be reduced by smarter, targeted training and with attention directed to female-specific hormonal status, biomechanics, and musculoskeletal architecture. An "estrogen advantage" appears to metabolically support enhanced mental endurance in physically demanding high-stress field conditions; a healthy estrogen environment is also essential for musculoskeletal health. The performance of female soldiers can be further enhanced by attention to equipment that serves their needs with seemingly simple solutions such as a suitable sports bra and personal protective equipment that accommodates the female anatomy. CONCLUSIONS Female physiological limits and performance have yet to be adequately defined as women move into new roles that were previously developed and reserved for men. Emerging evidence indicates much greater physical capacity and physiological resilience than previously postulated.
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Affiliation(s)
- Karmon D Dyches
- Military Operational Medicine Research Program, U.S. Army Medical Research and Development Command, Fort Detrick, MD 21702, USA
| | - Karl E Friedl
- Biophysics and Biomedical Modeling Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, USA
| | - Julie P Greeves
- Department of Army Health and Performance Research (AHPR), British Army, Andover, Hampshire SP11 8HT, UK
| | - Margaux F Keller
- Henry M Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20817, USA
| | - Holly L McClung
- Biophysics and Biomedical Modeling Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, USA
| | - Michael S McGurk
- Research and Analysis Directorate, U.S. Army Center for Initial Military Training, Fort Eustis, VA 23604, USA
| | - Kristin L Popp
- Military Performance Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, USA
| | - Deydre S Teyhen
- Chief, U.S. Army Medical Specialist Corps, U.S. Army Medical Command, Falls Church, VA 22042, USA
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Coombs CV, Wardle SL, Shroff R, Eisenhauer A, Tang JCY, Fraser WD, Greeves JP, O'Leary TJ. The effect of calcium supplementation on calcium and bone metabolism during load carriage in women: protocol for a randomised controlled crossover trial. BMC Musculoskelet Disord 2023; 24:496. [PMID: 37328859 DOI: 10.1186/s12891-023-06600-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 06/02/2023] [Indexed: 06/18/2023] Open
Abstract
BACKGROUND Military field exercises are characterised by high volumes of exercise and prolonged periods of load carriage. Exercise can decrease circulating serum calcium and increase parathyroid hormone and bone resorption. These disturbances to calcium and bone metabolism can be attenuated with calcium supplementation immediately before exercise. This randomised crossover trial will investigate the effect of calcium supplementation on calcium and bone metabolism, and bone mineral balance, during load carriage exercise in women. METHODS Thirty women (eumenorrheic or using the combined oral contraceptive pill, intrauterine system, or intrauterine device) will complete two experimental testing sessions either with, or without, a calcium supplement (1000 mg). Each experimental testing session will involve one 120 min session of load carriage exercise carrying 20 kg. Venous blood samples will be taken and analysed for biochemical markers of bone resorption and formation, calcium metabolism, and endocrine function. Urine will be collected pre- and post-load carriage to measure calcium isotopes for the calculation of bone calcium balance. DISCUSSION The results from this study will help identify whether supplementing women with calcium during load carriage is protective of bone and calcium homeostasis. TRIAL REGISTRATION NCT04823156 (clinicaltrials.gov).
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Affiliation(s)
- Charlotte V Coombs
- Army Health and Performance Research, Army Headquarters, Andover, SP11 8HT, UK
| | - Sophie L Wardle
- Army Health and Performance Research, Army Headquarters, Andover, SP11 8HT, UK
| | - Rukshana Shroff
- Renal Unit, UCL Great Ormond Street Hospital for Children NHS Foundation Trust and Institute of Child Health, London, UK
| | | | | | | | - Julie P Greeves
- Army Health and Performance Research, Army Headquarters, Andover, SP11 8HT, UK
| | - Thomas J O'Leary
- Army Health and Performance Research, Army Headquarters, Andover, SP11 8HT, UK.
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Edwards NA, Talarico MK, Chaudhari A, Mansfield CJ, Oñate J. Use of accelerometers and inertial measurement units to quantify movement of tactical athletes: A systematic review. APPLIED ERGONOMICS 2023; 109:103991. [PMID: 36841096 DOI: 10.1016/j.apergo.2023.103991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 01/25/2023] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
The dynamic work environments of tactical athletes are difficult to replicate in a laboratory. Accelerometers and inertial measurement units provide a way to characterize movement in the field. This systematic review identified how accelerometers and inertial measurement units are currently being used to quantify movement patterns of tactical athletes. Seven research and military databases were searched, producing 26,228 potential articles with 78 articles included in this review. The articles studied military personnel (73.1%), firefighters (19.2%), paramedics (3.8%), and law enforcement officers (3.8%). Accelerometers were the most used type of sensor, and physical activity was the primarily reported outcome variable. Seventy of the studies had fair or poor quality. Research on firefighters, emergency medical services, and law enforcement officers was limited. Future research should strive to make quantified movement data more accessible and user-friendly for non-research personnel, thereby prompting increased use in tactical athlete groups, especially first responder agencies.
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Affiliation(s)
- Nathan A Edwards
- School of Health and Rehabilitation Sciences, The Ohio State University, 453 W 10th Ave, Columbus, OH, 43210, USA; Human Performance Collaborative, The Ohio State University, 1961 Tuttle Park Place, Columbus, OH, 43210, USA; Sports Medicine Research Institute, The Ohio State University, 4835 Fred Taylor Drive, Columbus, OH, 43210, USA.
| | - Maria K Talarico
- Human Systems Integration Division, DEVCOM Analysis Center, U.S. Army Futures Command, 7188 Sustainment Rd, Aberdeen Proving Ground, MD, 21005, USA.
| | - Ajit Chaudhari
- School of Health and Rehabilitation Sciences, The Ohio State University, 453 W 10th Ave, Columbus, OH, 43210, USA; Sports Medicine Research Institute, The Ohio State University, 4835 Fred Taylor Drive, Columbus, OH, 43210, USA; Department of Mechanical and Aerospace Engineering, The Ohio State University, 201 W. 19th Avenue, Columbus, OH, 43210, USA; Department of Biomedical Engineering, The Ohio State University, 140 W. 19th Avenue, Columbus, OH, 43210, USA.
| | - Cody J Mansfield
- School of Health and Rehabilitation Sciences, The Ohio State University, 453 W 10th Ave, Columbus, OH, 43210, USA; Sports Medicine Research Institute, The Ohio State University, 4835 Fred Taylor Drive, Columbus, OH, 43210, USA.
| | - James Oñate
- School of Health and Rehabilitation Sciences, The Ohio State University, 453 W 10th Ave, Columbus, OH, 43210, USA; Human Performance Collaborative, The Ohio State University, 1961 Tuttle Park Place, Columbus, OH, 43210, USA; Division of Athletic Training, School of Health and Rehabilitation Sciences, The Ohio State University, 453 W 10th Ave, Columbus, OH, 43210, USA; Sports Medicine Research Institute, The Ohio State University, 4835 Fred Taylor Drive, Columbus, OH, 43210, USA.
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Tarnowski CA, Wardle SL, O’Leary TJ, Gifford RM, Greeves JP, Wallis GA. Measurement of Energy Intake Using the Principle of Energy Balance Overcomes a Critical Limitation in the Assessment of Energy Availability. SPORTS MEDICINE - OPEN 2023; 9:16. [PMID: 36811697 PMCID: PMC9947205 DOI: 10.1186/s40798-023-00558-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 02/04/2023] [Indexed: 02/24/2023]
Abstract
Prolonged low energy availability, which is the underpinning aetiology of the Relative Energy Deficiency in Sport and the Female and Male Athlete Triad frameworks, can have unfavourable impacts on both health and performance in athletes. Energy availability is calculated as energy intake minus exercise energy expenditure, expressed relative to fat free mass. The current measurement of energy intake is recognized as a major limitation for assessing energy availability due to its reliance on self-report methods, in addition to its short-term nature. This article introduces the application of the energy balance method for the measurement of energy intake, within the context of energy availability. The energy balance method requires quantification of the change in body energy stores over time, with concurrent measurement of total energy expenditure. This provides an objective calculation of energy intake, which can then be used for the assessment of energy availability. This approach, the Energy Availability - Energy Balance (EAEB) method, increases the reliance on objective measurements, provides an indication of energy availability status over longer periods and removes athlete burden to self-report energy intake. Implementation of the EAEB method could be used to objectively identify and detect low energy availability, with implications for the diagnosis and management of Relative Energy Deficiency in Sport and the Female and Male Athlete Triad.
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Affiliation(s)
- Caroline A. Tarnowski
- grid.6572.60000 0004 1936 7486School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT UK
| | - Sophie L. Wardle
- Army Health and Performance Research, Army Headquarters, Andover, UK ,grid.83440.3b0000000121901201Division of Surgery and Interventional Science, Department of Targeted Intervention, University College London, London, UK
| | - Thomas J. O’Leary
- Army Health and Performance Research, Army Headquarters, Andover, UK ,grid.83440.3b0000000121901201Division of Surgery and Interventional Science, Department of Targeted Intervention, University College London, London, UK
| | - Robert M. Gifford
- grid.511172.10000 0004 0613 128XBritish Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, UK ,grid.415490.d0000 0001 2177 007XResearch and Clinical Innovation, Royal Centre of Defence Medicine, Birmingham, UK
| | - Julie P. Greeves
- Army Health and Performance Research, Army Headquarters, Andover, UK ,grid.83440.3b0000000121901201Division of Surgery and Interventional Science, Department of Targeted Intervention, University College London, London, UK ,grid.8273.e0000 0001 1092 7967Norwich Medical School, University of East Anglia, Norwich, UK
| | - Gareth A. Wallis
- grid.6572.60000 0004 1936 7486School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT UK
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11
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Friedl KE, Gifford RM. Integrating women into ground close combat roles: an opportunity to reflect on universal paradigms of arduous training. BMJ Mil Health 2023; 169:1-2. [PMID: 32796014 PMCID: PMC9887368 DOI: 10.1136/bmjmilitary-2020-001568] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2020] [Indexed: 02/03/2023]
Affiliation(s)
- Karl E. Friedl
- Science & Technology Office, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
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12
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O'Leary TJ, Perrett C, Coombs CV, Double RL, Keay N, Wardle SL, Greeves JP. Menstrual disturbances in British Servicewomen: A cross-sectional observational study of prevalence and risk factors. Front Nutr 2022; 9:984541. [PMID: 36337622 PMCID: PMC9626978 DOI: 10.3389/fnut.2022.984541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 09/29/2022] [Indexed: 12/04/2022] Open
Abstract
Female athletes are at increased risk of menstrual disturbances. The prevalence of menstrual disturbances in British Servicewomen and the associated risk factors is unknown. All women under 45 years in the UK Armed Forces were invited to complete a survey about demographics, menstrual function, eating and exercise behaviors, and psychological well-being. 3,022 women participated; 18% had oligomenorrhoea or amenorrhoea in the last 12 months, 25% had a history of amenorrhoea, and 14% had delayed menarche. Women who sleep ≥ 8 h were at a lower risk of a history of amenorrhoea than women who sleep ≤ 5 h [odds ratio (95% confidence intervals) = 0.65 (0.48, 0.89), p = 0.006]. Women who completed > 10 days of field exercise in the last 12 months were at higher risk of a history of amenorrhoea than women completing no field exercise [1.45 (1.13, 1.85), p = 0.004]. Women at high risk of an eating disorder (FAST score >94) were at higher risk of oligomenorrhoea or amenorrhoea [1.97 (1.26, 3.04), p = 0.002] and history of amenorrhoea [2.14 (1.63, 2.79), p < 0.001]. Women with symptoms of anxiety or depression were at higher risk of a history of amenorrhoea [1.46 (1.20, 1.77) and 1.48 (1.22, 1.79), p < 0.001]. British Servicewomen had a similar prevalence of menstrual disturbances to some endurance athletes. Eating disorders, sleep behaviors, and management of mental health, provide targets for protecting health of the reproductive axis.
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Affiliation(s)
- Thomas J. O'Leary
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
- UCL Division of Surgery and Interventional Science, London, United Kingdom
- *Correspondence: Thomas J. O'Leary
| | - Caitlin Perrett
- UCL Division of Surgery and Interventional Science, London, United Kingdom
| | - Charlotte V. Coombs
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
| | - Rebecca L. Double
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
| | - Nicky Keay
- UCL Division of Medicine, London, United Kingdom
| | - Sophie L. Wardle
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
- UCL Division of Surgery and Interventional Science, London, United Kingdom
| | - Julie P. Greeves
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
- UCL Division of Surgery and Interventional Science, London, United Kingdom
- Norwich Medical School, University of East Anglia, Norwich, United Kingdom
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13
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O'Leary TJ, Izard RM, Tang JCY, Fraser WD, Greeves JP. Sex differences in tibial adaptations to arduous training: An observational cohort study. Bone 2022; 160:116426. [PMID: 35470123 DOI: 10.1016/j.bone.2022.116426] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 04/12/2022] [Accepted: 04/19/2022] [Indexed: 12/31/2022]
Abstract
Military training increases tibial density and size, but it is unknown if men and women adapt similarly to the same arduous training. Seventy-seven men and 57 women not using hormonal contraceptives completed this study. Tibial volumetric bone mineral density (vBMD) and geometry were measured by peripheral quantitative computed tomography (4%, 14%, 38%, and 66% sites) at the start (week 1) and end (week 14) of British Army basic training. Training increased trabecular vBMD (4% site in men; 4% and 14% sites in women), cortical vBMD (38% site), total area (14% and 38% sites), trabecular area (14% site), cortical area and thickness (14%, 38%, and 66% sites), periosteal perimeter (14%, 38%, and 66% sites), and all indices of estimated strength (14%, 38%, and 66% sites); and, decreased endosteal perimeter (66% site) in men and women (all p ≤ 0.045). The increase in trabecular vBMD (4% and 14% sites) was greater in women and the increases in cortical area and strength (38% site) were greater in men (sex × time interactions, all p ≤ 0.047). P1NP increased and βCTX and sclerostin decreased during training in men and women, consistent with adaptive bone formation. PTH decreased in men but increased in women. Arduous weight-bearing activity increased the density and size of the tibia after 14 weeks. Women experienced similar tibial adaptations as men, however, a greater increase in trabecular vBMD in women compared with men could be due to higher loading at this skeletal site in women, whereas the small increase in cortical area could be due to inhibitory effects of oestradiol.
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Affiliation(s)
- Thomas J O'Leary
- Army Health and Performance Research, Army HQ, Andover, UK; Division of Surgery and Interventional Science, UCL, London, UK
| | | | | | - William D Fraser
- Norwich Medical School, University of East Anglia, Norwich, UK; Norfolk and Norwich University Hospital, Norwich, UK
| | - Julie P Greeves
- Army Health and Performance Research, Army HQ, Andover, UK; Division of Surgery and Interventional Science, UCL, London, UK; Norwich Medical School, University of East Anglia, Norwich, UK.
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14
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Wardle SL, O'Leary TJ, McClung JP, Pasiakos SM, Greeves JP. Feeding female soldiers: Consideration of sex-specific nutrition recommendations to optimise the health and performance of military personnel. J Sci Med Sport 2021; 24:995-1001. [PMID: 34452842 DOI: 10.1016/j.jsams.2021.08.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 06/25/2021] [Accepted: 08/11/2021] [Indexed: 12/25/2022]
Abstract
Appropriate nutrition recommendations are required to optimise the health and performance of military personnel, yet limited data are available on whether male and female military personnel have different nutrition requirements. OBJECTIVES To consider the evidence for sex-specific nutrition requirements to optimise the health and performance of military personnel. DESIGN Narrative review. METHODS Published literature was reviewed, with a focus on sex-specific requirements, in the following areas: nutrition for optimising muscle mass and function, nutrition during energy deficit, and nutrition for reproductive and bone health. RESULTS There are limited data on sex differences in protein requirements but extant data suggest that, despite less muscle mass, on average, in women, sex-specific protein feeding strategies are not required to optimise muscle mass in military-aged individuals. Similarly, despite sex differences in metabolic and endocrine responses to energy deficit, current data do not suggest a requirement for sex-specific feeding strategies during energy deficit. Energy deficit impairs health and performance, most notably bone and reproductive health and these impairments are greater for women. Vitamin D, iron and calcium are important nutrients to protect the bone health of female military personnel due to increased risk of stress fracture. CONCLUSIONS Women have an increased incidence of bone injuries, less muscle mass and are more susceptible to the negative effects of energy deficit, including compromised reproductive health. However, there are limited data on sex differences in response to various nutrition strategies designed to improve these elements of health and performance. Future studies should evaluate whether sex-specific feeding recommendations are required.
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Affiliation(s)
- Sophie L Wardle
- Army Health and Performance Research, Army Headquarters, United Kingdom; Division of Surgery and Interventional Science, University College London, United Kingdom.
| | - Thomas J O'Leary
- Army Health and Performance Research, Army Headquarters, United Kingdom; Division of Surgery and Interventional Science, University College London, United Kingdom
| | - James P McClung
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, United States of America
| | - Stefan M Pasiakos
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, United States of America
| | - Julie P Greeves
- Army Health and Performance Research, Army Headquarters, United Kingdom; Division of Surgery and Interventional Science, University College London, United Kingdom; Norwich Medical School, University of East Anglia, United Kingdom
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15
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Gifford RM, O'Leary TJ, Wardle SL, Double RL, Homer NZM, Howie AF, Greeves JP, Anderson RA, Woods DR, Reynolds RM. Reproductive and metabolic adaptation to multistressor training in women. Am J Physiol Endocrinol Metab 2021; 321:E281-E291. [PMID: 34191631 DOI: 10.1152/ajpendo.00019.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 06/07/2021] [Indexed: 11/22/2022]
Abstract
Hypothalamic-pituitary-gonadal (HPG) axis suppression in exercising women can be caused by low energy availability (EA), but the impact of a real-world, multistressor training environment on reproductive and metabolic function is unknown. This study aimed to characterize reproductive and metabolic adaptation in women undertaking basic military training. A prospective cohort study in women undertaking 11-month initial military training (n = 47) was carried out. Dynamic low-dose 1-h gonadotrophin-releasing hormone (GnRH) tests were completed after 0 and 7 mo of training. Urine progesterone was sampled weekly throughout. Body composition (dual X-ray absorptiometry), fasting insulin resistance (homeostatic modeling assessment 2, HOMA2), leptin, sex steroids, anti-Müllerian hormone (AMH), and inhibin B were measured after 0, 7, and 11 mo with an additional assessment of body composition at 3 mo. Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) responses were suppressed after 7 mo (both P < 0.001). Among noncontraceptive users (n = 20), 65% had regular (23-35 days) cycles preenrollment, falling to 24% by 7 mo of training. Of women in whom urine progesterone was measured (n = 24), 87% of cycles showed no evidence of ovulation. There was little change in AMH, LH, and estradiol, although inhibin B and FSH increased (P < 0.05). Fat mass fluctuated during training but at month 11 was unchanged from baseline. Fat-free mass did not change. Visceral adiposity, HOMA2, and leptin increased (all P < 0.001). HPG axis suppression with anovulation occurred in response to training without evidence of low EA. Increased insulin resistance may have contributed to the observed pituitary and ovarian dysfunction. Our findings are likely to represent an adaptive response of reproductive function to the multistressor nature of military training.NEW & NOTEWORTHY We characterized reproductive endocrine adaptation to prolonged arduous multistressor training in women. We identified marked suppression of hypothalamic-pituitary-gonadal (HPG) axis function during training but found no evidence of low energy availability despite high energy requirements. Our findings suggest a complex interplay of psychological and environmental stressors with suppression of the HPG axis via activation of the hypothalamic-pituitary adrenal (HPA) axis. The neuroendocrine impact of nonexercise stressors on the HPG axis during arduous training should be considered.
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Affiliation(s)
- Robert M Gifford
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
- Research & Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
| | - Thomas J O'Leary
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
| | - Sophie L Wardle
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
| | - Rebecca L Double
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
| | - Natalie Z M Homer
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
- Mass Spectrometry Core, Edinburgh Clinical Research Facility, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - A Forbes Howie
- Medical Research Council Centre for Reproductive Health, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Julie P Greeves
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
- Norwich Medical School, University of East Anglia, Norwich, United Kingdom
| | - Richard A Anderson
- Medical Research Council Centre for Reproductive Health, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - David R Woods
- Research & Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
- Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, United Kingdom
| | - Rebecca M Reynolds
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
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O'Leary TJ, Wardle SL, Gifford RM, Double RL, Reynolds RM, Woods DR, Greeves JP. Tibial Macrostructure and Microarchitecture Adaptations in Women During 44 Weeks of Arduous Military Training. J Bone Miner Res 2021; 36:1300-1315. [PMID: 33856703 DOI: 10.1002/jbmr.4290] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/01/2021] [Accepted: 03/12/2021] [Indexed: 12/14/2022]
Abstract
Bone adapts to unaccustomed, high-impact loading but loses mechanosensitivity quickly. Short periods of military training (≤12 weeks) increase the density and size of the tibia in women. The effect of longer periods of military training, where the incidence of stress fracture is high, on tibial macrostructure and microarchitecture in women is unknown. This observational study recruited 51 women (age 19 to 30 years) at the start of 44 weeks of British Army Officer training. Tibial volumetric bone mineral density (vBMD), geometry, and microarchitecture were measured by high-resolution peripheral quantitative computed tomography (HRpQCT). Scans of the right tibial metaphysis (4% site) and diaphysis (30% site) were performed at weeks 1, 14, 28, and 44. Measures of whole-body areal bone mineral density (aBMD) were obtained using dual-energy X-ray absorptiometry (DXA). Blood samples were taken at weeks 1, 28, and 44, and were analyzed for markers of bone formation and resorption. Trabecular vBMD increased from week 1 to 44 at the 4% site (3.0%, p < .001). Cortical vBMD decreased from week 1 to 14 at the 30% site (-0.3%, p < .001). Trabecular area decreased at the 4% site (-0.4%); trabecular bone volume fraction (3.5%), cortical area (4.8%), and cortical thickness (4.0%) increased at the 4% site; and, cortical perimeter increased at the 30% site (0.5%) from week 1 to 44 (p ≤ .005). Trabecular number (3.5%) and thickness (2.1%) increased, and trabecular separation decreased (-3.1%), at the 4% site from week 1 to 44 (p < .001). Training increased failure load at the 30% site from week 1 to 44 (2.5%, p < .001). Training had no effect on aBMD or markers of bone formation or resorption. Tibial macrostructure and microarchitecture continued to adapt across 44 weeks of military training in young women. Temporal decreases in cortical density support a role of intracortical remodeling in the pathogenesis of stress fracture. © 2021 Crown copyright. Journal of Bone and Mineral Research © 2021 American Society for Bone and Mineral Research (ASBMR). This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.
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Affiliation(s)
- Thomas J O'Leary
- Army Health and Performance Research, Army Headquarters, Andover, UK.,Division of Surgery and Interventional Science, University College London (UCL), London, UK
| | - Sophie L Wardle
- Army Health and Performance Research, Army Headquarters, Andover, UK.,Division of Surgery and Interventional Science, University College London (UCL), London, UK
| | - Robert M Gifford
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK.,Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK
| | - Rebecca L Double
- Army Health and Performance Research, Army Headquarters, Andover, UK
| | - Rebecca M Reynolds
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - David R Woods
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK.,Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK.,Northumbria and Newcastle National Health Service (NHS) Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, UK.,University of Newcastle, Newcastle, UK
| | - Julie P Greeves
- Army Health and Performance Research, Army Headquarters, Andover, UK.,Division of Surgery and Interventional Science, University College London (UCL), London, UK.,Norwich Medical School, University of East Anglia, Norwich, UK
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