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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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Smotrova E, Li S, Silberschmidt VV. Trabecula-level mechanoadaptation: Numerical analysis of morphological changes. Comput Biol Med 2024; 168:107720. [PMID: 38006828 DOI: 10.1016/j.compbiomed.2023.107720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 09/22/2023] [Accepted: 11/15/2023] [Indexed: 11/27/2023]
Abstract
BACKGROUND Bone is a living material that, unlike man-made ones, demonstrates continuous adaptation of its structure and mechanical properties to resist the imposed mechanical loading. Adaptation in trabecular bone is characterised by improvement of its stiffness in the loading direction and respective realignment of trabecular load-bearing architecture. Considerable experimental and simulation evidence of trabecular bone adaptation to its mechanical environment at the tissue- and organ-levels was obtained, while little attention was given to the trabecula-level of this process. This study aims to describe and classify load-driven morphological changes at the level of individual trabeculae and to propose their drivers. METHOD For this purpose, a well-established mechanoregulation-based numerical model of bone adaptation was implemented in a user-defined subroutine that changed the structural and mechanical properties of trabeculae based on the magnitude of a mechanical stimulus. This subroutine was used in conjunction with finite-element models of variously shaped structures representing trabeculae loaded in compression or shear. RESULTS In all analysed cases, trabeculae underwent morphological evolution under applied compressive or shear loading. Among twelve cases analysed, six main mechanisms of morphological evolution were established: reorientation, splitting, merging, full resorption, thinning, and thickening. Moreover, all simulated cases presented the ability to reduce the mean value of von Mises stress while increasing their ability to resist compressive/shear loading during adaptation. CONCLUSION This study evaluated morphological and mechanical changes in trabeculae of different shapes in response to compressive or shear loadings and compared them based on the analysis of von Mises stress distribution as well as profiles of normal and shear stresses in the trabeculae at different stages of their adaptation.
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Affiliation(s)
- Ekaterina Smotrova
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough, UK; Laboratory of Mechanics of Biocompatible Materials and Devices, Perm National Research Polytechnic University, Komsomolsky Ave., 29, Perm, 614000, Russia.
| | - Simin Li
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough, UK
| | - Vadim V Silberschmidt
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough, UK
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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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Physiological biomarker monitoring during arduous military training: Maintaining readiness and performance. J Sci Med Sport 2022:S1440-2440(22)00502-3. [PMID: 36631385 DOI: 10.1016/j.jsams.2022.12.005] [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: 06/15/2022] [Revised: 12/06/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Physiological and psychological stressors can degrade soldiers' readiness and performance during military training and operational environments. Integrative and holistic assessments of biomarkers across diverse human performance optimization domains during multistressor training can be leveraged to provide actionable insight to military leadership regarding service member health and readiness. DESIGN/METHOD A broad categorization of biomarkers, to include biochemical measures, bone and body composition, psychometric assessments, movement screening, and physiological load can be incorporated into robust analytical pipelines for understanding the complex factors that impact military human performance. RESULTS In this perspective commentary we overview the rationale, selection, and methodologies for monitoring biomarker domains that are relevant to military research and specifically highlight methods that have been incorporated in a research program funded by the Office of Naval Research, Code 34 Biological and Physiological Monitoring and Modeling of Warfighter Performance. CONCLUSIONS The integration of screening and continuous monitoring methodologies via robust analytical approaches will provide novel insight for military leaders regarding health, performance, and readiness outcomes during multistressor military training.
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Warden SJ, Sventeckis AM, Surowiec RK, Fuchs RK. Enhanced Bone Size, Microarchitecture, and Strength in Female Runners with a History of Playing Multidirectional Sports. Med Sci Sports Exerc 2022; 54:2020-2030. [PMID: 35941520 PMCID: PMC9669197 DOI: 10.1249/mss.0000000000003016] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Female runners have high rates of bone stress injuries (BSIs), including stress reactions and fractures. The current study explored multidirectional sports (MDS) played when younger as a potential means of building stronger bones to reduce BSI risk in these athletes. METHODS Female collegiate-level cross-country runners were recruited into groups: 1) RUN, history of training and/or competing in cross-country, recreational running/jogging, swimming, and/or cycling only, and 2) RUN + MDS, additional history of training and/or competing in soccer or basketball. High-resolution peripheral quantitative computed tomography was used to assess the distal tibia, common BSI sites (diaphysis of the tibia, fibula, and second metatarsal), and high-risk BSI sites (base of the second metatarsal, navicular, and proximal diaphysis of the fifth metatarsal). Scans of the radius were used as control sites. RESULTS At the distal tibia, RUN + MDS ( n = 18) had enhanced cortical area (+17.1%) and thickness (+15.8%), and greater trabecular bone volume fraction (+14.6%) and thickness (+8.3%) compared with RUN ( n = 14; all P < 0.005). Failure load was 19.5% higher in RUN + MDS ( P < 0.001). The fibula diaphysis in RUN + MDS had an 11.6% greater total area and a 11.1% greater failure load (all P ≤ 0.03). At the second metatarsal diaphysis, total area in RUN + MDS was 10.4% larger with greater cortical area and thickness and 18.6% greater failure load (all P < 0.05). RUN + MDS had greater trabecular thickness at the base of the second metatarsal and navicular and greater cortical area and thickness at the proximal diaphysis of the fifth metatarsal (all P ≤ 0.02). No differences were observed at the tibial diaphysis or radius. CONCLUSIONS These findings support recommendations that athletes delay specialization in running and play MDS when younger to build a more robust skeleton and potentially prevent BSIs.
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Affiliation(s)
- Stuart J. Warden
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis
- La Trobe Sport and Exercise Medicine Research Centre, La Trobe University, Bundoora, Victoria, AUSTRALIA
| | - Austin M. Sventeckis
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis
| | - Rachel K. Surowiec
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis
- Department of Biomedical Engineering¸ Purdue School of Engineering and Technology, Indiana University-Purdue University Indianapolis, Indianapolis
| | - Robyn K. Fuchs
- Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis
- Indiana Center for Musculoskeletal Health, Indiana University, Indianapolis
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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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