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Borgenström J, Kyröläinen H, Pihlainen K, Vaara JP, Ojanen T. Effects of male paratroopers' initial body composition on changes in physical performance and recovery during a 20-day winter military field training. Appl Physiol Nutr Metab 2024; 49:437-446. [PMID: 38084583 DOI: 10.1139/apnm-2023-0002] [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] [Indexed: 01/10/2024]
Abstract
Changes in physiological markers and physical performance in relation to paratroopers' initial body composition were investigated during a 20-day winter military field training (MFT) and the subsequent 10-day recovery period. Body composition, serum hormone concentrations and enzymatic biomarkers, and physical performance of 58 soldiers were measured before, during, and after MFT. Comparisons were done according to soldiers' body fat percentage before MFT between low-fat (<12% body fat) and high-fat (>12% body fat) groups. Correlations between body fat percentage preceding MFT and changes in muscle mass, physical performance, and serum hormone concentrations and enzymatic biomarkers were investigated. It was hypothesized that soldiers with a higher fat percentage would have smaller decrements in muscle mass, physical performance, and serum testosterone concentration. The change in muscle and fat mass was different between groups (p < 0.001) as the low-fat group lost 0.8 kg of muscle mass and 2.0 kg of fat mass, while there was no change in muscle mass and a loss of 3.7 kg of fat mass in the high-fat group during MFT. Fat percentage before MFT correlated with the changes in muscle mass (R2 = 0.26, p < 0.001), serum testosterone concentration (R2 = 0.22, p < 0.001), and evacuation test time (R2 = 0.10, p < 0.05) during MFT. The change in muscle mass was correlated with the changes in evacuation test time (R2 = 0.11, p < 0.05) and countermovement jump test results (R2 = 0.13, p < 0.01) during MFT. Soldiers with a higher initial fat percentage lost less muscle mass, and had smaller decrements in some aspects of physical performance, as well as in serum testosterone concentration during MFT.
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Affiliation(s)
- Jere Borgenström
- Faculty of Sport and Health Sciences, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland
| | - Heikki Kyröläinen
- Faculty of Sport and Health Sciences, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland
- Department of Leadership and Military Pedagogy, National Defence University, P.O. Box 7, 00861 Helsinki, Finland
| | - Kai Pihlainen
- Defence Command, Finnish Defence Forces, P.O. Box 919, 00131 Helsinki, Finland
| | - Jani P Vaara
- Department of Leadership and Military Pedagogy, National Defence University, P.O. Box 7, 00861 Helsinki, Finland
| | - Tommi Ojanen
- Finnish Defence Research Agency, Finnish Defence Forces, P.O. Box 5, 04401 Järvenpää, Finland
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Kierkegaard M, Tegern M, Halvarsson A, Broman L, Larsson H. High Physical Exposure During Female Recruits' Basic Military Training in Sweden-A Descriptive Study. Mil Med 2024; 189:e674-e682. [PMID: 37625078 PMCID: PMC10898928 DOI: 10.1093/milmed/usad335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/24/2023] [Accepted: 08/13/2023] [Indexed: 08/27/2023] Open
Abstract
INTRODUCTION There is a knowledge gap concerning the occurrence of physical complaints/injuries, i.e., musculoskeletal disorders (MSD), among Swedish women who undergo basic military training (BMT). The aims were to describe prevalence and factors related to MSD and explore physical exposure and performance in Swedish female recruits during BMT. MATERIALS AND METHODS A total of 144 females (mean age 22 years) who underwent BMT in 2016 participated in this cross-sectional study. Data regarding self-reported MSD, physical performance, physical activity and exercise, motivation and mental and physical preparation, and physical exposure during BMT and perceived health were collected at the end of BMT through the Musculoskeletal Screening Protocol questionnaire. Additional data on muscle strength were retrieved from IsoKai isokinetic lift tests. Descriptive and analytic (paired samples t-test and logistic binary regression) statistics were used. RESULTS The prevalence of MSD was high, with 33% (n = 48) reporting MSD before BMT, 78% (n = 113) during, and 50% (n = 72) at the end of BMT. Knee and upper back were the most frequently reported MSD locations. Forty-four (30%) participants felt insufficiently physically prepared for BMT. The physical exposure was high with loaded marches/runs and carrying heavy loads as the most demanding tasks. The longest walking distance was reportedly 55 km, and the reported maximum load was 50 kg. Forty-five participants (31%) had carried a load representing over 50% of their body weight. Most participants reported good to excellent health at the end of BMT. There was a small (8 N) but significant (P = 0.045) increase in mean force over time. Two variables, MSD before BMT (odds ratio 2.24, P = 0.03) and being physically unprepared (odds ratio 3.03, P < 0.01), were associated with MSD at the end of BMT. CONCLUSION This study showed that the prevalence of MSD in Swedish female recruits was high before, during, and at the end of BMT, with knee and upper back as the most frequent locations. Although the physical exposure during BMT was occasionally high, self-rated health was mainly perceived as good to excellent at the end of BMT. Previous MSD and being physically unprepared were related to MSD at the end of BMT. These important and relevant findings indicate the necessity for implementing interventions to increase physical fitness and treat MSD at the beginning of BMT.
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Affiliation(s)
- Marie Kierkegaard
- Department of Neurobiology, Care Sciences and Society, Division of Physiotherapy, Karolinska Institutet, Stockholm SE-141 83, Sweden
- Academic Specialist Center, Center of Neurology, Stockholm Health Services, Stockholm SE-113 65, Sweden
| | - Matthias Tegern
- Department of Neurobiology, Care Sciences and Society, Division of Physiotherapy, Karolinska Institutet, Stockholm SE-141 83, Sweden
- Department of Community Medicine and Rehabilitation, Unit of Physiotherapy, Umeå University, Umeå SE-901 87, Sweden
| | - Alexandra Halvarsson
- Department of Neurobiology, Care Sciences and Society, Division of Physiotherapy, Karolinska Institutet, Stockholm SE-141 83, Sweden
- Women's Health and Allied Health Professionals Theme, Medical Unit Occupational therapy and Physiotherapy, Karolinska University Hospital, Stockholm SE-141 86, Sweden
| | - Lisbet Broman
- Department of Neurobiology, Care Sciences and Society, Division of Physiotherapy, Karolinska Institutet, Stockholm SE-141 83, Sweden
| | - Helena Larsson
- Department of Neurobiology, Care Sciences and Society, Division of Physiotherapy, Karolinska Institutet, Stockholm SE-141 83, Sweden
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Pihlainen K, Santtila M, Nindl BC, Raitanen J, Ojanen T, Vaara JP, Helén J, Nykänen T, Kyröläinen H. Changes in physical performance, body composition and physical training during military operations: systematic review and meta-analysis. Sci Rep 2023; 13:21455. [PMID: 38052976 PMCID: PMC10698179 DOI: 10.1038/s41598-023-48712-2] [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: 08/28/2023] [Accepted: 11/29/2023] [Indexed: 12/07/2023] Open
Abstract
Systematic review and meta-analysis applying PRISMA guidelines with a PICOS format was constructed to provide an overview of changes in physical performance, body composition and physical training in soldiers during prolonged (≥ 3 months) military operations. Twenty-four studies out of the screened 4431 records filled the inclusion criteria. A small decrease in endurance performance was the most consistent finding (Hedge's g [g] - 0.21, 95% CI - 0.01 to - 0.41) while small overall increases in maximal strength of the lower (g 0.33, 95% CI 0.16-0.50) and upper body (g 0.33, 95% CI 0.19-0.46) were observed. In addition, small increases in strength endurance (push-up, g 0.34, 95% CI 0.15-0.52; sit-up g 0.26, 95% CI 0.07-0.44) were observed. The overall changes in body composition were trivial. Heterogeneity in the outcome variables varied mainly between low to moderate. Large inter-individual variations were observed in physical training volume, including decrements especially in endurance training frequency and volume. A reduction in total training load was often associated with negative changes in body composition and physical performance according to the principle of training specificity. Individuals with higher initial fitness level were more susceptible to decrements in their physical performance during operation.
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Affiliation(s)
- K Pihlainen
- Human Performance Sector, Training Division, Defence Command, Helsinki, Finland.
| | - M Santtila
- Department of Leadership and Military Pedagogy, National Defence University, Helsinki, Finland
| | - B C Nindl
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - J Raitanen
- Faculty of Social Sciences (Health Sciences), Tampere University, Tampere, Finland
- UKK Institute for Health Promotion Research, Tampere, Finland
| | - T Ojanen
- Human Performance Division, Finnish Defence Research Agency, Tuusula, Finland
| | - J P Vaara
- Department of Leadership and Military Pedagogy, National Defence University, Helsinki, Finland
| | - J Helén
- Department of Leadership and Military Pedagogy, National Defence University, Helsinki, Finland
| | - T Nykänen
- Army Academy, Finnish Defence Forces, Lappeenranta, Finland
| | - H Kyröläinen
- Department of Leadership and Military Pedagogy, National Defence University, Helsinki, Finland
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyvaskyla, Finland
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Ojanen T, Pihlainen K, Vaara JP, Kyröläinen H. Physiological and physical performance changes during a 20-day winter military training course and its subsequent 10-day recovery period. Int J Circumpolar Health 2023; 82:2207287. [PMID: 37119213 PMCID: PMC10150620 DOI: 10.1080/22423982.2023.2207287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023] Open
Abstract
The present study investigated physiological, mental and physical performance changes during a 20-day winter military training course and the following 10-day recovery period. Fifty-eight (age 19 ± 1 years, height 182 ± 6 cm, body mass 78.5 ± 7.2 kg) male soldiers volunteered. Body composition, serum biomarker levels and performance tests were measured four times during the study. In addition, questionnaires were collected daily for subjective stress and rate of perceived exertion. The course induced significant declines in body (-3.9%, p < 0.05) and fat mass (-31.6%, p < 0.05) as well as in all assessed physical performance variables (-9.2 - -20.2%, p < 0.05), testosterone (-73.7%, p < 0.001) and IGF-1 concentrations (-43.6%, p < 0.001). At the same time, the sex hormone-binding globulin, creatine kinase, and C-reactive protein values increased significantly (46.3-1952.7%, p < 0.05). After the 10-day recovery period, the body composition and hormonal values returned to the baseline (p < 0.05), as did some physical performance variables, such as 2 min sit-ups and the evacuation test (p < 0.05). However, explosive force production in the upper and lower bodies remained unrecovered. The 20-day winter military training caused significant physiological and mental stress, as well as a drastic decline in physical performance even for highly physically fit soldiers, and the 10-day recovery period did not establish full recovery.
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Affiliation(s)
- Tommi Ojanen
- Human Performance Division, Finnish Defence Research Agency, Tuusula, Finland
| | - Kai Pihlainen
- Training Division, Defence Command, Helsinki, Finland
| | - Jani P Vaara
- Department of Leadership and Military Pedagogy, National Defence University, Helsinki, Finland
| | - Heikki Kyröläinen
- Department of Leadership and Military Pedagogy, National Defence University, Helsinki, Finland
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
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Larsson J, Olsson MC, Bremander A, Dencker M. Physiological Demands and Characteristics of Movement During Simulated Combat. Mil Med 2023; 188:3496-3505. [PMID: 35678321 PMCID: PMC10629984 DOI: 10.1093/milmed/usac163] [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: 02/14/2022] [Revised: 03/24/2022] [Accepted: 05/26/2022] [Indexed: 11/14/2022] Open
Abstract
INTRODUCTION Military tasks place considerable physiological demands on the soldier. It is therefore important to know the energy expenditure of soldiers while solving tasks in different environments. The purpose of this study was to describe the cardiorespiratory demands of certain movements and activities on ground combat soldiers during military field operations using body sensors and simulated combat. MATERIALS AND METHODS Movement characteristics and cardiorespiratory responses were assessed in 42 soldiers (three women) in the Swedish Army. The different posts assessed were commander, combat engineer, driver, and gunner. The military field exercises examined were urban operations and retrograde operations in rough terrain. Measurements included (1) body mass, (2) heart rate (HR) including maximal (HRmax), (3) velocity, (4) accelerations/decelerations, and (5) distance moved. Maximal aerobic capacity (V̇O2peak, mL·kg-1·min-1) was tested in a laboratory setting when wearing combat gear and body armor. RESULTS There was a weak positive correlation (r = 0.41 and 0.28, both P < .05) between VO2peak and percentage of time over 40% and 50% of maximal aerobic capacity during simulated combat. No differences were found for the different posts in time spent over 40% or 50% of maximal aerobic capacity and 76% of their HRmax (P > .05). Wearing combat gear and additional load while solving tasks resulted in mean HR varying between 98 and 111 beats·min-1, corresponding with 50-57% of the soldiers HRmax. Studying all exercises, mean HR was 105 ± 11 beats min-1, 54 ± 5% of HRmax corresponding to light work intensity. Soldiers performed between 2.8 and 4.9 accelerations/min in the different exercises. A significant correlation between V̇O2peak (mL kg-1 min-1) and acceleration and m/min were found, implying that soldiers with good aerobic capacity were able to cope better with tasks requiring quick movements. CONCLUSION Conducting military operations in urban terrain and retrograde operations in rough terrain strains ground combat soldiers' cardiorespiratory system, with work intensities close to 40% of maximal aerobic capacity in 15-33% of mission time. Tasks with external load carriage include change of direction, accelerations, bounds, and jumping over obstacles, and physical fitness tests should replicate this. Findings in this study also add objective data to the physiological demands of work performed by combat soldiers while conducting urban operations and retrograde operations in rough terrain. These findings could be used to develop a model for classifying work demands for ground combat forces.
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Affiliation(s)
- Jonas Larsson
- Department of Medical Imaging and Physiology, Skåne University Hospital, Department of Translational medicine, Lund University, Malmö S-20502, Sweden
- Department of Environmental and Biosciences, School of Business, Innovation and Sustainability, Halmstad University, Halmstad S-30118, Sweden
- Göta Engineer Regiment, Swedish Armed Forces, Eksjö S-57528, Sweden
| | - M Charlotte Olsson
- Department of Environmental and Biosciences, School of Business, Innovation and Sustainability, Halmstad University, Halmstad S-30118, Sweden
| | - Ann Bremander
- Department of Clinical Sciences, Lund, Section of Rheumatology, Lund University, Lund S-22100, Sweden
- Department of Regional Health Research, University of Southern Denmark, Odense, Syddanmark DK-5000, Denmark
| | - Magnus Dencker
- Department of Medical Imaging and Physiology, Skåne University Hospital, Department of Translational medicine, Lund University, Malmö S-20502, Sweden
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Zheng H, Cheng J, Ho HC, Zhu B, Ding Z, Du W, Wang X, Yu Y, Fei J, Xu Z, Zhou J, Yang J. Evaluating the short-term effect of ambient temperature on non-fatal outdoor falls and road traffic injuries among children and adolescents in China: a time-stratified case-crossover study. FRONTIERS OF ENVIRONMENTAL SCIENCE & ENGINEERING 2023; 17:105. [PMID: 37033401 PMCID: PMC10067518 DOI: 10.1007/s11783-023-1705-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 06/19/2023]
Abstract
UNLABELLED Although studies have suggested that non-optimal temperatures may increase the risk of injury, epidemiological studies focusing on the association between temperature and non-fatal injury among children and adolescents are limited. Therefore, we investigated the short-term effect of ambient temperature on non-fatal falls and road traffic injuries (RTIs) among students across Jiangsu Province, China. Meteorological data and records of non-fatal outdoor injuries due to falls and RTIs among students aged 6-17 were collected during 2018-2020. We performed a time-stratified case-crossover analysis with a distributed lag nonlinear model to examine the effect of ambient temperature on the risk of injury. Individual meteorological exposure was estimated based on the address of the selected school. We also performed stratified analyses by sex, age, and area. A total of 57322 and 5455 cases of falls and RTIs were collected, respectively. We observed inverted U-shaped curves for temperature-injury associations, with maximum risk temperatures at 18 °C (48th of daily mean temperature distribution) for falls and 22 °C (67th of daily mean temperature distribution) for RTIs. The corresponding odds ratios (95% confidence intervals) were 2.193 (2.011, 2.391) and 3.038 (1.988, 4.644) for falls and RTIs, respectively. Notably, there was a significant age-dependent trend in which the temperature effect on falls was greater in older students (P-trend < 0.05). This study suggests a significant association between ambient temperature and students' outdoor falls and RTIs. Our findings may help advance tailored strategies to reduce the incidence of outdoor falls and RTIs in children and adolescents. ELECTRONIC SUPPLEMENTARY MATERIAL Supplementary material is available in the online version of this article at 10.1007/s11783-023-1705-1 and is accessible for authorized users.
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Affiliation(s)
- Hao Zheng
- Department of Environmental Health, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, 210009 China
| | - Jian Cheng
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, 230032 China
- Anhui Province Key Laboratory of Major Autoimmune Disease, Hefei, 230032 China
| | - Hung Chak Ho
- Department of Anaesthesiology, School of Clinical Medicine, The University of Hong Kong, Hong Kong, 999077 China
| | - Baoli Zhu
- Department of Environmental Health, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, 210009 China
| | - Zhen Ding
- Department of Environmental Health, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, 210009 China
| | - Wencong Du
- Department of Noncommunicable Diseases, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, 210009 China
| | - Xin Wang
- Department of Child and Adolescent Health Promotion, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, 210009 China
| | - Yang Yu
- Department of Environmental Health, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, 210009 China
| | - Juan Fei
- Department of Environmental Health, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, 210009 China
| | - Zhiwei Xu
- School of Public Health, University of Queensland, Queensland, 4006 Australia
| | - Jinyi Zhou
- Department of Noncommunicable Diseases, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, 210009 China
| | - Jie Yang
- Department of Child and Adolescent Health Promotion, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, 210009 China
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Chua CG, Thong BYH. Inflammatory Arthritis Among Military Servicemen From a Rheumatology Center in Singapore. Mil Med 2023; 188:e473-e478. [PMID: 34190324 DOI: 10.1093/milmed/usab246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/02/2021] [Accepted: 06/11/2021] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Musculoskeletal disorders are one of the most common reasons military servicemen seek medical care during their line of duty. This study aims to review the clinical profile and outcomes of military personnel with inflammatory arthritis (IA) referred to a specialist rheumatology center in Singapore. MATERIALS AND METHODS Consecutive new case referrals from the Singapore Armed Forces medical centers during the study period January 1, 2010, to December 31, 2019, were retrospectively studied. RESULTS There were 123 referrals, comprising 112 (91.1%) males, with the majority being Chinese (110, 89.4%). The mean age was 25.5 ± 11.1 years. The most common diagnoses were gout (including chronic tophaceous gout; 34, 27.6%), spondyloarthritis (18, 14.6%), palindromic rheumatism (8, 6.5%), rheumatoid arthritis (4, 3.3%), and juvenile idiopathic arthritis (4, 3.3%). Among servicemen with gout, all were male, the majority (31, 91.3%) were Chinese, and mean age was 34.1 ± 8.8 years. Mean body mass index (BMI) was 27.5 ± 3.9 kg/m2, of which 41.2% had moderate-risk and 47.1% high-risk BMI for cardiovascular disease and diabetes mellitus (DM). Comorbidities included hyperlipidemia (14), hypertension (6), and type 2 DM (3). Urate lowering therapy was initiated in 27 (79.4%) patients, comprising allopurinol (85.2%), probenecid (11.1%), and their combination (3.7%). One patient developed allopurinol-induced hepatitis; none had severe cutaneous adverse reactions. Among the remaining patients with IA, conventional synthetic disease-modifying antirheumatic drugs (DMARDs) used were sulfasalazine (8), methotrexate (4), hydroxychloroquine (4), and leflunomide (2). Biologic DMARDs used in five patients comprised adalimumab (3) and golimumab (2). CONCLUSION Servicemen with IA and good functional status can still be physically fit and deployable into certain combat and service support vocations. This will optimize manpower resources in military organizations with a shrinking young workforce.
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Affiliation(s)
- Choon-Guan Chua
- Department of Rheumatology, Allergy and Immunology, Tan Tock Seng Hospital, 308433, Singapore
| | - Bernard Yu-Hor Thong
- Department of Rheumatology, Allergy and Immunology, Tan Tock Seng Hospital, 308433, Singapore
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Wang Y, Lin L, Xu Z, Wang L, Huang J, Zhou M, Li G. Have residents adapted to heat wave and cold spell in the 21st century? Evidence from 136 Chinese cities. ENVIRONMENT INTERNATIONAL 2023; 173:107811. [PMID: 36878108 DOI: 10.1016/j.envint.2023.107811] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/02/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Global climate change has increased the probability and intensity of extreme weather events. The adverse health effect of extreme temperature has gone through a temporal variation over years. Time-series data including city-level daily cardiovascular death records and meteorological data were collected from 136 Chinese cities during 2006 and 2019. A time-varying distributed lag model with interaction terms was applied to assess the temporal change of mortality risk and attributable mortality of heat wave and cold spell. The mortality effect of heat wave generally increased and that of cold spell decreased significantly in the total population during the study period. The heat wave effect increased especially among the female and people aged 65 to 74. As for the cold spell, the reduced susceptibility was detected both in the temperate and cold climatic zone. Our findings appeal for counterpart measures corresponding to sub-populations and regions responding to future extreme climate events from the public and individuals.
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Affiliation(s)
- Yuxin Wang
- Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, 38 Xueyuan Road, Haidian District, Beijing 100191, China
| | - Lin Lin
- National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Xicheng District, Beijing 100050, China
| | - Zhihu Xu
- Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, 38 Xueyuan Road, Haidian District, Beijing 100191, China
| | - Lijun Wang
- National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Xicheng District, Beijing 100050, China
| | - Jing Huang
- Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, 38 Xueyuan Road, Haidian District, Beijing 100191, China
| | - Maigeng Zhou
- National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Xicheng District, Beijing 100050, China.
| | - Guoxing Li
- Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, 38 Xueyuan Road, Haidian District, Beijing 100191, China; Environmental Research Group, MRC Centre for Environment and Health, Sir Michael Uren Building, Imperial College London, White City Campus, 80-92 Wood Lane, London W12 0BZ, United Kingdom.
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Efficacy of two intermittent cooling strategies during prolonged work-rest intervals in the heat with personal protective gear compared with a control condition. Eur J Appl Physiol 2023; 123:1125-1134. [PMID: 36651993 DOI: 10.1007/s00421-023-05139-x] [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: 05/06/2022] [Accepted: 01/09/2023] [Indexed: 01/19/2023]
Abstract
INTRODUCTION Personal protective equipment (PPE) inhibits heat dissipation and elevates heat strain. Impaired cooling with PPE warrants investigation into practical strategies to improve work capacity and mitigate exertional heat illness. PURPOSE Examine physiological and subjective effects of forearm immersion (FC), fan mist (MC), and passive cooling (PC) following three intermittent treadmill bouts while wearing PPE. METHODS Twelve males (27 ± 6 years; 57.6 ± 6.2 ml/kg/min; 78.3 ± 8.1 kg; 183.1 ± 7.2 cm) performed three 50-min (10 min of 40%, 70%, 40%, 60%, 50% vVO2max) treadmill bouts in the heat (36 °C, 30% relative humidity). Thirty minutes of cooling followed each bout, using one of the three strategies per trial. Rectal temperature (Tcore), skin temperature (Tsk), heart rate (HR), heart rate recovery (HRR), rating of perceived exertion (RPE), thirst, thermal sensation (TS), and fatigue were obtained. Repeated-measures analysis of variance (condition x time) detected differences between interventions. RESULTS Final Tcore was similar between trials (P > .05). Cooling rates were larger in FC and MC vs PC following bout one (P < .05). HRR was greatest in FC following bouts two (P = .013) and three (P < .001). Tsk, fluid consumption, and sweat rate were similar between all trials (P > .05). TS and fatigue during bout three were lower in MC, despite similar Tcore and HR. CONCLUSION Utilizing FC and MC during intermittent work in the heat with PPE yields some thermoregulatory and cardiovascular benefit, but military health and safety personnel should explore new and novel strategies to mitigate risk and maximize performance under hot conditions while wearing PPE.
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Bordonie NC, Saunders MJ, de Zevallos JO, Kurti SP, Luden ND, Crance JH, Baur DA. Dietary nitrate supplementation enhances heavy load carriage performance in military cadets. Eur J Appl Physiol 2023; 123:91-102. [PMID: 36175576 DOI: 10.1007/s00421-022-05056-5] [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: 08/19/2022] [Accepted: 09/20/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE To determine the effects of dietary nitrate (NO3-) supplementation on physiological responses, cognitive function, and performance during heavy load carriage in military cadets. METHODS Ten healthy males (81.0 ± 6.5 kg; 180.0 ± 4.5 cm; 56.2 ± 3.7 ml·kg·min-1 VO2max) consumed 140 mL·d-1 of beetroot juice (BRJ; 12.8 mmol NO3-) or placebo (PL) for six d preceding an exercise trial, which consisted of 45 min of load carriage (55% body mass) at 4.83 km·h-1 and 1.5% grade, followed by a 1.6-km time-trial (TT) at 4% grade. Gas exchange, heart rate, and perceptual responses were assessed during constant-load exercise and the TT. Cognitive function was assessed immediately prior to, during, and post-exercise via the psychomotor vigilance test (PVT). RESULTS Post-TT HR (188 ± 7.1 vs. 185 ± 7.4; d = 0.40; p = 0.03), mean tidal volume (2.15 ± 0.27 vs. 2.04 ± 0.23; p = 0.02; d = 0.47), and performance (770.9 ± 78.2 s vs. 809.8 ± 61.4 s; p = 0.03; d = 0.63) were increased during the TT with BRJ versus PL. There were no effects of BRJ on constant-load gas exchange or perceptual responses, and cognitive function was unchanged at all time points. CONCLUSION BRJ supplementation improves heavy load carriage performance in military cadets possibly as a result of attenuated respiratory muscle fatigue, rather than enhanced exercise economy.
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Affiliation(s)
- Nicholas C Bordonie
- Department of Kinesiology, James Madison University, Harrisonburg, VA, 22807, USA
| | - Michael J Saunders
- Department of Kinesiology, James Madison University, Harrisonburg, VA, 22807, USA
| | - Joaquin Ortiz de Zevallos
- Department of Kinesiology, School of Health and Human Development, University of Virginia, Charlottesville, VA, 22904, USA
| | - Stephanie P Kurti
- Department of Kinesiology, James Madison University, Harrisonburg, VA, 22807, USA
| | - Nicholas D Luden
- Department of Kinesiology, James Madison University, Harrisonburg, VA, 22807, USA
| | - Jenny H Crance
- Infirmary, Virginia Military Institute, Lexington, VA, 24450, USA
| | - Daniel A Baur
- Department of Human Performance and Wellness, Virginia Military Institute, 208 Cormack Hall, Lexington, VA, 24450, USA.
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11
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Koltun KJ, Bird MB, Lovalekar M, Martin BJ, Mi Q, Nindl BC. Changes in eating pathology symptoms during initial military training in men and women and associations with BMI and injury risk. Eat Behav 2023; 48:101687. [PMID: 36463664 DOI: 10.1016/j.eatbeh.2022.101687] [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: 03/09/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022]
Abstract
Nutritional fitness, which comprises food choices, meal timing, and dietary intake behaviors, is an important component of military service member health and performance that has garnered recent attention. This study utilized generalized linear mixed effects modeling (GLMM) to investigate changes in eating pathology symptoms in men and women during initial military training (Marine Corps Officer Candidates School (OCS)). Associations among eating pathology, musculoskeletal injury risk and BMI were also assessed. This investigation includes data from the Eating Pathology Symptoms Inventory (EPSI) and BMI at the start of OCS (n = 598: Male n = 469, Female n = 129) and end of the 10-week program (n = 413: Male n = 329, Female n = 84), and injury surveillance throughout. At baseline, female candidates presented with greater body dissatisfaction, binge eating, purging, and restricting, but lower negative attitudes toward obesity compared to male candidates (p < 0.001). Eating symptoms changed during military training indicated by decreased body dissatisfaction in women (p = 0.003), decreased excessive exercise and negative attitudes toward obesity in men (p < 0.001), decreased cognitive restraint (p < 0.001), restricting (p < 0.001), purging (p = 0.013), and muscle building (p < 0.001) and increased binge eating (p < 0.001) in both sexes. Changes in restricting were significantly related to changes in BMI during training (p < 0.05). The likelihood of future injury was 108 % higher in female candidates than males and decreased by 5 % for each unit increase in excessive exercise. Eating attitudes and behaviors change during military training environments and are associated with military health and readiness outcomes including BMI and injury risk.
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Affiliation(s)
- Kristen J Koltun
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, 3860 S. Water St., Pittsburgh, PA 15203, USA.
| | - Matthew B Bird
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, 3860 S. Water St., Pittsburgh, PA 15203, USA
| | - Mita Lovalekar
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, 3860 S. Water St., Pittsburgh, PA 15203, USA
| | - Brian J Martin
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, 3860 S. Water St., Pittsburgh, PA 15203, USA
| | - Qi Mi
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, 3860 S. Water St., Pittsburgh, PA 15203, USA
| | - Bradley C Nindl
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, 3860 S. Water St., Pittsburgh, PA 15203, USA
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12
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Short-term PM exposure and social stress cause pulmonary and cardiac dysfunction. Toxicol Lett 2022; 370:66-73. [PMID: 36122649 DOI: 10.1016/j.toxlet.2022.09.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/25/2022] [Accepted: 09/12/2022] [Indexed: 11/20/2022]
Abstract
Ambient particulate matter (PM) exposure increases risk for cardiopulmonary health problems which may be exacerbated in a stressful environment. Co-exposure to PM and stress characterizes the experience of many deployed military personnel and first responders but has not been thoroughly investigated. This is especially relevant to military personnel who have been exposed to high PM levels in conjunction with stressful military conflict situations. To understand the mechanisms and time-course of the health consequences following burn pit exposure, we exposed mice to moderate levels of ambient PM less than 2.5 μM in diameter (PM2.5) alone or in combination with psychological stress. We found male mice exposed to PM2.5 alone or in combination with stress had significantly reduced pulmonary function when subjected to methacholine, indicating increased airway hyperreactivity. These mice experienced increased goblet cell hyperplasia in their lungs, with no change in alveolar density. Mice exposed to PM2.5 and/or stress also exhibited reduced cardiac contractility, right ventricular (RV) output, and changes in RV capillary density and cardiac inflammatory markers. Taken together, these data indicate that short-term exposure to PM2.5 with or without stress causes a clear reduction in pulmonary and cardiac function. We believe that this model is well-suited for the study of military and other occupational exposures, and future work will identify potential mechanisms, including the inflammatory progression of these co-exposures.
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13
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Pihlainen K, Kyröläinen H, Santtila M, Ojanen T, Raitanen J, Häkkinen K. Effects of Combined Strength and Endurance Training on Body Composition, Physical Fitness, and Serum Hormones During a 6-Month Crisis Management Operation. J Strength Cond Res 2022; 36:2361-2370. [PMID: 33337694 PMCID: PMC9394488 DOI: 10.1519/jsc.0000000000003902] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Pihlainen, K, Kyröläinen, H, Santtila, M, Ojanen, T, Raitanen, J, and Häkkinen, K. Effects of combined strength and endurance training on body composition, physical fitness, and serum hormones during a 6-month crisis management operation. J Strength Cond Res 36(9): 2361-2370, 2022-Very few studies have examined the impact of training interventions on soldier readiness during an international military operation. Therefore, the present study investigated the effects of combined strength and endurance training on body composition, physical performance, and hormonal status during a 6-month international military deployment consisting of typical peacekeeping tasks, e.g., patrolling, observation, and on-base duties. Soldiers ( n = 78) were randomly allocated to a control group (C) or one of 3 combined whole-body strength and endurance training groups with varying strength-to-endurance training emphasis (Es = 25/75%, SE = 50/50% or Se = 75/25% of strength/endurance training). Body composition, physical performance (3000-m run, standing long jump [SLJ], isometric maximal voluntary contraction of the lower [MVC lower] and upper extremities [MVC upper ], muscle endurance tests), and selected serum hormone concentrations were determined prior to training (PRE), and after 9 (MID) and 19 (POST) weeks of training. Within- and between-group changes were analyzed using linear regression models. The average combined strength and endurance training frequency of the total subject group was 3 ± 2 training sessions per week. No changes were observed in physical performance variables in the intervention groups, whereas SLJ decreased by 1.9% in C ( p < 0.05). Maximal voluntary contraction lower increased by 12.8% in the combined intervention group ( p < 0.05), and this was significantly different to C ( p < 0.05). Testosterone-to-cortisol ratio increased in SE and Se ( p < 0.05), whereas no change was observed in C. The intervention groups maintained or improved their physical performance during deployment, which is beneficial for operational readiness. However, the high interindividual variation observed in training adaptations highlights the importance of training individualization during prolonged military operations.
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Affiliation(s)
- Kai Pihlainen
- Training Division, Helsinki, Defence Command, Finland
| | - Heikki Kyröläinen
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
- Department of Military Pedagogy and Leadership, National Defence University, Finnish Defence Forces, Helsinki, Finland
| | - Matti Santtila
- Department of Military Pedagogy and Leadership, National Defence University, Finnish Defence Forces, Helsinki, Finland
| | - Tommi Ojanen
- Finnish Defence Research Agency, Finnish Defence Forces, Tuusula, Tuusula, Finland
| | - Jani Raitanen
- Faculty of Social Sciences (Health Sciences), Tampere University, Tampere, Finland; and
- UKK Institute for Health Promotion Research, Tampere, Finland
| | - Keijo Häkkinen
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
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14
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Bird MB, Mi Q, Koltun KJ, Lovalekar M, Martin BJ, Fain A, Bannister A, Vera Cruz A, Doyle TLA, Nindl BC. Unsupervised Clustering Techniques Identify Movement Strategies in the Countermovement Jump Associated With Musculoskeletal Injury Risk During US Marine Corps Officer Candidates School. Front Physiol 2022; 13:868002. [PMID: 35634154 PMCID: PMC9132209 DOI: 10.3389/fphys.2022.868002] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 04/05/2022] [Indexed: 11/15/2022] Open
Abstract
Musculoskeletal injuries (MSKI) are a significant burden on the military healthcare system. Movement strategies, genetics, and fitness level have been identified as potential contributors to MSKI risk. Screening measures associated with MSKI risk are emerging, including novel technologies, such as markerless motion capture (mMoCap) and force plates (FP) and allow for field expedient measures in dynamic military settings. The aim of the current study was to evaluate movement strategies (i.e., describe variables) of the countermovement jump (CMJ) in Marine officer candidates (MOCs) via mMoCap and FP technology by clustering variables to create distinct movement strategies associated with MSKI sustained during Officer Candidates School (OCS). 728 MOCs were tested and 668 MOCs (Male MOCs = 547, Female MOCs = 121) were used for analysis. MOCs performed 3 maximal CMJs in a mMoCap space with FP embedded into the system. De-identified MSKI data was acquired from internal OCS reports for those who presented to the OCS Physical Therapy department for MSKI treatment during the 10 weeks of OCS training. Three distinct clusters were formed with variables relating to CMJ kinetics and kinematics from the mMoCap and FPs. Proportions of MOCs with a lower extremity and torso MSKI across clusters were significantly different (p < 0.001), with the high-risk cluster having the highest proportions (30.5%), followed by moderate-risk cluster (22.5%) and low-risk cluster (13.8%). Kinetics, including braking rate of force development (BRFD), braking net impulse and propulsive net impulse, were higher in low-risk cluster compared to the high-risk cluster (p < 0.001). Lesser degrees of flexion and shorter CMJ phase durations (braking phase and propulsive phase) were observed in low-risk cluster compared to both moderate-risk and high-risk clusters. Male MOCs were distributed equally across clusters while female MOCs were primarily distributed in the high-risk cluster. Movement strategies (i.e., clusters), as quantified by mMoCap and FPs, were successfully described with MOCs MSKI risk proportions between clusters. These results provide actionable thresholds of key performance indicators for practitioners to use for screening measures in classifying greater MSKI risk. These tools may add value in creating modifiable strength and conditioning training programs before or during military training.
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Affiliation(s)
- Matthew B. Bird
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, United States
- *Correspondence: Matthew B. Bird,
| | - Qi Mi
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, United States
| | - Kristen J. Koltun
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, United States
| | - Mita Lovalekar
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, United States
| | - Brian J. Martin
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, United States
| | - AuraLea Fain
- Biomechanics, Physical Performance and Exercise Research Group, Department of Health Sciences, Macquarie University, Sydney, NSW, Australia
| | | | | | - Tim L. A. Doyle
- Biomechanics, Physical Performance and Exercise Research Group, Department of Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Bradley C. Nindl
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, United States
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15
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Nindl BC, Kyröläinen H. Editorial: Military human performance optimization: Contemporary issues for sustained and improved readiness. Eur J Sport Sci 2022; 22:1-3. [PMID: 34937525 DOI: 10.1080/17461391.2021.2019319] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This issue of the European Journal of Sport Science includes 8 invited state-of-the-science narrative reviews by well-established researchers in the area of military performance focused on (a) physical training; (b) musculoskeletal injury; (c) adaptive bone formation and stress fracture prevention; (d) sex differences in responses to military stress; (e) load monitoring in military settings; (g) circulating biomarkers related to resilience during military stress; (H) military nutrition research; and (I) development of military exoskeletons. Important historical, current and future scientific and research information and guidance within the context of sustained and improved military physical performance and readiness are provided. Conclusions and recommendations for protecting Soldier health and resiliency include: (1) combined physical training emphasizing higher intensity but lower volume; (2) musculoskeletal injury risk factors most supported from the literature include: female sex, prior injury and low fitness; (3) adequate sleep, vitamin D, calcium, and energy availability are all critical for creating a resilient skeleton protecting against stress fractures; (4) differences between men and women when exposed to military stress include cardiovascular strain, fat oxidation, and psychological health risk; (5) biomarkers (cortisol, epi/norepi, ILs 4, 6, 10, 18 and TNF-alpha, IGF-I, testosterone, DHEA) offer insight for internal stress; (6) monitoring physiological training load should include consideration for multiple inputs, rather than a single measure; (7) nutrition optimization includes determining operational requirements, nutritional practices and nutrient delivery strategies; and (8) future generation exoskeletons will achieve a better balance of intended movement based on individual user and interactions with internal and external constraints.
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Affiliation(s)
- Bradley C Nindl
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Heikki Kyröläinen
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
- Department of Leadership and Military Pedagogy, National Defence University, Helsinki, Finland
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16
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Liang M, Ding X, Yao Z, Duan L, Xing X, Sun Y. Effects of ambient temperature and fall-related injuries in Ma'anshan, Anhui Province, China: a distributed lag nonlinear analysis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:58092-58103. [PMID: 34105075 DOI: 10.1007/s11356-021-14663-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/27/2021] [Indexed: 06/12/2023]
Abstract
Despite the significant economic cost of falls and injuries to individuals and communities, little is known about the impact of meteorological factors on the incidence of fall-related injuries (FRIs). Therefore, a time-series study was conducted to explore the effects of meteorological factors on FRIs in Ma'anshan City, East China. Injury data from 2011 to 2017 were collected from the National Injury Monitoring Station in Ma'anshan City. A distributed lag nonlinear model was used in this study to evaluate the correlation between ambient temperature and fall injuries. The results showed a significant exposure-response relationship between temperature and FRIs in Ma'anshan City. The high temperatures increased the risk of FRIs (RR = 1.110; 95% CI, 1.005-1.225; lag 0). The lag effect appeared at lag 10 (RR = 1.032; 95% CI, 1.003-1.063), and then gradually remained stable after lag 25 (RR = 1.077; 95% CI, 1.045-1.110). The effect of ambient temperature varied with age and gender. The lag effect of high temperature appeared in the male group after lag 15 (RR = 1.042; 95% CI, 1.006-1.079). In contrast, the effect of the female group appeared for the first time at lag 0 (RR = 1.187; 95% CI, 1.042-1.352). And the ≥ 60 years subgroup seemed to be more sensitive in low temperature (RR = 1.017; 95% CI, 1.004-1.031; lag 0; RR = 1.003; 95% CI, 1.000-1.007; lag 25). The cumulative result is similar to the single-day effect. From the results, this study would help the establishment of fall-related injury prediction and provide evidence for the formulation and implementation of preventive strategies and measures in the future.
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Affiliation(s)
- Mingming Liang
- Department of Epidemiology and Health Statistics, School of Public Health, Anhui Medical University, No. 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Xiuxiu Ding
- Department of Epidemiology and Health Statistics, School of Public Health, Anhui Medical University, No. 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Zhenhai Yao
- Anhui Meteorological Service Center, Anhui Meteorological Bureau, Hefei, 230000, Anhui, China
| | - Leilei Duan
- National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 100050, China
| | - Xiuya Xing
- Department of Chronic Noncommunicable Disease Control and Prevention, Anhui Provincial Center for Disease Control and Prevention, No. 12560, Fanhua Road, Hefei, 230601, Anhui, China.
| | - Yehuan Sun
- Department of Epidemiology and Health Statistics, School of Public Health, Anhui Medical University, No. 81 Meishan Road, Hefei, 230032, Anhui, China.
- Center for Injury Control and Prevention, School of Public Health, Anhui Medical University, Hefei, 230032, Anhui, China.
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17
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Optimization of the Critical Speed Concept for Tactical Professionals: A Brief Review. Sports (Basel) 2021; 9:sports9080106. [PMID: 34437367 PMCID: PMC8402554 DOI: 10.3390/sports9080106] [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: 04/15/2021] [Revised: 06/01/2021] [Accepted: 07/21/2021] [Indexed: 11/16/2022] Open
Abstract
Tactical professionals often depend on their physical ability and fitness to perform and complete occupational tasks to successfully provide public services or survive on the battlefield. Critical speed (CS), or maximal aerobic steady-state, is a purported measure that predicts performance, prescribes exercise, and detects training adaptions with application to tactical professionals. The CS concept has the versatility to adapt to training with load carriage as an integrated bioenergetic system approach for assessment. The aims of this review are to: (1) provide an overview of tactical populations and the CS concept; (2) describe the different methods and equipment used in CS testing; (3) review the literature on CS associated with tactical occupational tasks; and (4) demonstrate the use of CS-derived exercise prescriptions for tactical populations.
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18
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Applying Force Plate Technology to Inform Human Performance Programming in Tactical Populations. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11146538] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Force plate assessments, such as countermovement jumps and isometric mid-thigh pulls, examine performances (e.g., jump height, force, power) and movement strategies (e.g., asymmetries, durations), and are best suited to characterize and monitor physical capabilities, not predict injuries. To begin applying force plate technologies, users must first; (1) develop a data management plan to visualize and capture data over time; (2) select appropriate force plates for their scenario; (3) design appropriate testing protocols to ensure valid and reliable data. Force plate assessments may be added to existing testing, serve as separate testing batteries for annual profile testing to compare individuals and understand initial physical capabilities, or for more frequent testing (i.e., monthly or weekly) to monitor training-related adaptations or neuromuscular fatigue. Although these assessments inform evidence-based program designs, human performance practitioners must understand the considerations for conducting appropriate force plate testing, as well as proper visualizations and management of force plate data. Thus, the aim of this review is to provide evidence-based practices for utilizing force plates in tactical populations (e.g., military, firefighters, police). This includes best practices to implement testing for performance profiling, training adaptations, and monitoring neuromuscular fatigue and force asymmetries. Of note, due to the large amount of force-time metrics to choose from, this article provides general examples of important metrics to monitor and training recommendations based on changes to these force-time metrics, followed by specific examples in three case studies.
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19
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Orr R, Sakurai T, Scott J, Movshovich J, Dawes JJ, Lockie R, Schram B. The Use of Fitness Testing to Predict Occupational Performance in Tactical Personnel: A Critical Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:7480. [PMID: 34299926 PMCID: PMC8307946 DOI: 10.3390/ijerph18147480] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/03/2021] [Accepted: 07/08/2021] [Indexed: 11/16/2022]
Abstract
Tactical personnel work in an occupation that involves tasks requiring a high level of cardiovascular fitness as well as muscular strength and endurance. The aim of this literature review was to identify and critique studies investigating the relationship between physical fitness, quantified by fitness assessment measures, and occupational task performance. Databases were searched for relevant articles which assessed a fitness measure and a measure of occupational performance. A total of 15 articles were included and were deemed to be of acceptable methodological quality (8.4/12 on the Critical Appraisal Skills Programme checklist). Included articles assessed a variety of fitness attributes and occupational tasks. Across tactical groups, there appear to be no standardized fitness tests that can determine occupational performance, with aerobic fitness, anaerobic fitness, strength, endurance, power, and agility all being associated with occupational task performance. A wide range of fitness assessments appears to be required to predict occupational performance within tactical personnel. Efforts should be made to base fitness assessments on occupational demands unique to both the environment and requirements of each individual tactical unit.
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Affiliation(s)
- Robin Orr
- Faculty of Health Science and Medicine, Bond University, Robina, QLD 4229, Australia; (T.S.); (J.S.); (J.M.); (B.S.)
- Tactical Research Unit, Bond University, Robina, QLD 4229, Australia; (J.J.D.); (R.L.)
| | - Takato Sakurai
- Faculty of Health Science and Medicine, Bond University, Robina, QLD 4229, Australia; (T.S.); (J.S.); (J.M.); (B.S.)
| | - Jordan Scott
- Faculty of Health Science and Medicine, Bond University, Robina, QLD 4229, Australia; (T.S.); (J.S.); (J.M.); (B.S.)
| | - Jason Movshovich
- Faculty of Health Science and Medicine, Bond University, Robina, QLD 4229, Australia; (T.S.); (J.S.); (J.M.); (B.S.)
| | - J. Jay Dawes
- Tactical Research Unit, Bond University, Robina, QLD 4229, Australia; (J.J.D.); (R.L.)
- Health and Human Performance Faculty, Oklahoma State University, Stillwater, OK 74074, USA
| | - Robert Lockie
- Tactical Research Unit, Bond University, Robina, QLD 4229, Australia; (J.J.D.); (R.L.)
- Department of Kinesiology, California State University, Fullerton, CA 92835, USA
| | - Ben Schram
- Faculty of Health Science and Medicine, Bond University, Robina, QLD 4229, Australia; (T.S.); (J.S.); (J.M.); (B.S.)
- Tactical Research Unit, Bond University, Robina, QLD 4229, Australia; (J.J.D.); (R.L.)
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20
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Peel JS, McNarry MA, Heffernan SM, Nevola VR, Kilduff LP, Waldron M. The Effect of Dietary Supplements on Endurance Exercise Performance and Core Temperature in Hot Environments: A Meta-analysis and Meta-regression. Sports Med 2021; 51:2351-2371. [PMID: 34129223 PMCID: PMC8514372 DOI: 10.1007/s40279-021-01500-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2021] [Indexed: 01/07/2023]
Abstract
BACKGROUND The ergogenic effects of dietary supplements on endurance exercise performance are well-established; however, their efficacy in hot environmental conditions has not been systematically evaluated. OBJECTIVES (1) To meta-analyse studies investigating the effects of selected dietary supplements on endurance performance and core temperature responses in the heat. Supplements were included if they were deemed to: (a) have a strong evidence base for 'directly' improving thermoneutral endurance performance, based on current position statements, or (b) have a proposed mechanism of action that related to modifiable factors associated with thermal balance. (2) To conduct meta-regressions to evaluate the moderating effect of selected variables on endurance performance and core temperature responses in the heat following dietary supplementation. METHODS A search was performed using various databases in May 2020. After screening, 25 peer-reviewed articles were identified for inclusion, across three separate meta-analyses: (1) exercise performance; (2) end core temperature; (3) submaximal core temperature. The moderating effect of several variables were assessed via sub-analysis and meta-regression. RESULTS Overall, dietary supplementation had a trivial significant positive effect on exercise performance (Hedges' g = 0.18, 95% CI 0.007-0.352, P = 0.042), a trivial non-significant positive effect on submaximal core temperature (Hedges' g = 0.18, 95% CI - 0.021 to 0.379, P = 0.080) and a small non-significant positive effect on end core temperature (Hedges' g = 0.20, 95% CI - 0.041 to 0.439, P = 0.104) in the heat. There was a non-significant effect of individual supplements on exercise performance (P = 0.973) and submaximal core temperature (P = 0.599). However, end core temperature was significantly affected by supplement type (P = 0.003), which was attributable to caffeine's large significant positive effect (n = 8; Hedges' g = 0.82, 95% CI 0.433-1.202, P < 0.001) and taurine's medium significant negative effect (n = 1; Hedges' g = - 0.96, 95% CI - 1.855 to - 0.069, P = 0.035). CONCLUSION Supplements such as caffeine and nitrates do not enhance endurance performance in the heat, with caffeine also increasing core temperature responses. Some amino acids might offer the greatest performance benefits in the heat. Exercising in the heat negatively affected the efficacy of many dietary supplements, indicating that further research is needed and current guidelines for performance in hot environments likely require revision.
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Affiliation(s)
- Jennifer S Peel
- A-STEM Centre, College of Engineering, Swansea University, Swansea, UK.
| | - Melitta A McNarry
- A-STEM Centre, College of Engineering, Swansea University, Swansea, UK
| | - Shane M Heffernan
- A-STEM Centre, College of Engineering, Swansea University, Swansea, UK
| | - Venturino R Nevola
- A-STEM Centre, College of Engineering, Swansea University, Swansea, UK
- Defence Science and Technology Laboratory (Dstl), Fareham, Hampshire, UK
| | - Liam P Kilduff
- A-STEM Centre, College of Engineering, Swansea University, Swansea, UK
- Welsh Institute of Performance Science, Swansea University, Swansea, UK
| | - Mark Waldron
- A-STEM Centre, College of Engineering, Swansea University, Swansea, UK
- Welsh Institute of Performance Science, Swansea University, Swansea, UK
- School of Science and Technology, University of New England, Armidale, NSW, Australia
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21
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Vaara JP, Groeller H, Drain J, Kyröläinen H, Pihlainen K, Ojanen T, Connaboy C, Santtila M, Agostinelli P, Nindl BC. Physical training considerations for optimizing performance in essential military tasks. Eur J Sport Sci 2021; 22:43-57. [PMID: 34006204 DOI: 10.1080/17461391.2021.1930193] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Physically demanding essential military tasks include load carriage, manual material handling and casualty evacuation. This narrative review characterizes the main physical attributes related to performance of these occupational tasks and reviews physical training intervention studies in military settings to improve performance in these military tasks. Load carriage performance requires both aerobic and neuromuscular fitness with greater emphasis on maximal strength and absolute maximal oxygen uptake, especially when carrying heavier loads. In manual material handling, maximal strength and power are strongly associated with discrete lifting, while muscular strength, muscular endurance and aerobic fitness are also associated with repetitive lifting performance. Maximal strength including grip strength, muscular endurance, absolute maximal oxygen uptake and anaerobic capacity are associated with casualty evacuation performance. The results of the present review particularly emphasize the role of muscular fitness in successful performance of the reviewed military occupational tasks. Training intervention studies indicate that load carriage performance can be effectively improved by combining strength, aerobic and specific load carriage training. Improvement in maximal lifting capacity can be achieved by strength training or combined strength and aerobic training, while strength and aerobic training alone, or their combination are effective in improving repetitive lifting, and carry tasks. Only a few studies are available for casualty evacuation and the results are inconclusive but may indicate benefits of strength or combined training. Moreover, emphasis on lower volume but higher intensity in combined training may be a feasible and effective mode to improve military occupational performance in recruits and active-duty soldiers.
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Affiliation(s)
- Jani P Vaara
- National Defence University, Department of Leadership and Military Pedagogy, Helsinki, Finland
| | - Herbert Groeller
- Centre for Medical and Exercise Physiology, School of Medicine, University of Wollongong, Wollongong, Australia
| | - Jace Drain
- Defence Science and Technology Group, Fishermans Bends, Australia
| | - Heikki Kyröläinen
- National Defence University, Department of Leadership and Military Pedagogy, Helsinki, Finland.,Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Kai Pihlainen
- Defence Command, Training Division, Finnish Defence Forces, Helsinki, Finland
| | - Tommi Ojanen
- Finnish Defence Research Agency, Human Performance Division, Finnish Defence Forces, Tuusula, Finland
| | - Chris Connaboy
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, University of Pittsburgh, Pittsburgh, PA, USA
| | - Matti Santtila
- National Defence University, Department of Leadership and Military Pedagogy, Helsinki, Finland
| | - Philip Agostinelli
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, University of Pittsburgh, Pittsburgh, PA, USA
| | - Brad C Nindl
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, University of Pittsburgh, Pittsburgh, PA, USA
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22
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Conkright WR, O'Leary TJ, Wardle SL, Greeves JP, Beckner ME, Nindl BC. SEX DIFFERENCES IN THE PHYSICAL PERFORMANCE, PHYSIOLOGICAL, AND PSYCHO-COGNITIVE RESPONSES TO MILITARY OPERATIONAL STRESS. Eur J Sport Sci 2021; 22:99-111. [PMID: 33840352 DOI: 10.1080/17461391.2021.1916082] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Combat roles are physically demanding and expose service personnel to operational stressors such as high levels of physical activity, restricted nutrient intake, sleep loss, psychological stress, and environmental extremes. Women have recently integrated into combat roles, but our knowledge of the physical, physiological, and psycho-cognitive responses to these operational stressors in women is limited. The aim of this narrative review was to evaluate the evidence for sex-specific physical, physiological, and psycho-cognitive responses to real, and simulated, military operational stress. Studies examining physical and cognitive performance, body composition, metabolism, hypothalamic-pituitary-gonadal axis, and psychological health outcomes were evaluated. These studies report that women expend less energy and lose less body mass and fat-free mass, but not fat mass, than men. Despite having similar physical performance decrements as men during operational stress, women experience greater physiological strain than men completing the same physical tasks, but this may be attributed to differences in fitness. From limited data, military operational stress suppresses hypothalamic-pituitary-gonadal, but not hypothalamic-pituitary-adrenal, axis function in both sexes. Men and women demonstrate different psychological and cognitive responses to operational stress, including disturbances in mood, with women having a higher risk of post-traumatic stress symptoms compared with men. Based on current evidence, separate strategies to maximize selection and combat training are not warranted until further data directly comparing men and women are available. However, targeted exercise training programs may be advisable to offset the physical performance gap between sexes and optimize performance prior to inevitable declines caused by intense military operations.
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Affiliation(s)
- William R Conkright
- Department of Sports Medicine and Nutrition, Neuromuscular Research Laboratory & Warrior Human Performance Research Center, University of Pittsburgh, United States
| | - Thomas J O'Leary
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom.,Division of Surgery and Interventional Science, University College London, London, United Kingdom
| | - Sophie L Wardle
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom.,Division of Surgery and Interventional Science, University College London, London, United Kingdom
| | - Julie P Greeves
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom.,Division of Surgery and Interventional Science, University College London, London, United Kingdom.,Norwich Medical School, University of East Anglia, Norwich, United Kingdom
| | - Meaghan E Beckner
- Department of Sports Medicine and Nutrition, Neuromuscular Research Laboratory & Warrior Human Performance Research Center, University of Pittsburgh, United States
| | - Bradley C Nindl
- Department of Sports Medicine and Nutrition, Neuromuscular Research Laboratory & Warrior Human Performance Research Center, University of Pittsburgh, United States
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23
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Sedliak M, Sedliak P, Vaara JP. Effects of 6-Month Military Deployment on Physical Fitness, Body Composition, and Selected Health-Related Biomarkers. J Strength Cond Res 2021; 35:1074-1081. [PMID: 30829983 DOI: 10.1519/jsc.0000000000002885] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Sedliak, M, Sedliak, P, and Vaara, JP. Effects of 6-month military deployment on physical fitness, body composition, and selected health-related biomarkers. J Strength Cond Res 35(4): 1074-1081, 2021-The purpose was to study the effects of 6-month deployment to Afghanistan on physical performance, anthropometrical, and health-related biochemical parameters in soldiers with sedentary to light physical workload shifts. Twenty-five male soldiers (30 ± 4 years) volunteered and were measured before and after the 6-month deployment. Another 25 home-land-based male soldiers (30 ± 6 years) served as controls. Total body fat percentage decreased in deployed soldiers (Pre: 23.2 ± 5.3 vs. Post: 20.8 ± 5.5%, p < 0.05), whereas no change was observed in control (20.2 ± 6.9 vs. 20.5 ± 7.0%). Physical performance improved in deployed soldiers in 4 × 10-m shuttle run (10.86 ± 0.90 vs. 10.49 ± 0.63 seconds) and pull-up test to failure (4.7 ± 3.7 vs. 7.5 ± 6.7 rep.) (p < 0.05) but not in the controls for the respective tests (10.28 ± 0.74 vs. 10.40 ± 0.76 seconds and 10.2 ± 7.8 vs. 10.2 ± 7.5 rep.). Deployed soldiers also improved 5-km run with a simulated combat gear time (29.2 ± 3.1 vs. 27.4 ± 3.0 minutes), whereas in control the time increased (26.4 ± 2.9 vs. 27.8 ± 2.6 minutes, p < 0.05). Load at maximum power output in bench press was improved in deployed soldiers (51.6 ± 11.3 vs. 56.2 ± 12.6 kg, p < 0.05). Serum glucose and creatinine decreased (5.46 ± 0.53 vs. 4.87 ± 0.74 mmol·L-1 and 87.4 ± 10.7 vs. 80.9 ± 10.2 μmmol·L-1, respectively), and hemoglobin and hematocrite increased (15.13 ± 0.82 vs. 16.75 ± 0.85 g·dl-1 and 45.3 ± 1.5 vs. 48.1 ± 2.4%, respectively, p < 0.05) in the deployment group. In conclusion, after 6-month deployment consisting of sedentary and low physical occupational load, soldiers were able to increase their physical fitness and decrease their body fat content and improve selected health-related biochemical parameters. Therefore, the adoption and promotion of leisure-time physical activity in soldiers during deployments is essential to maintain combat readiness.
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Affiliation(s)
- Milan Sedliak
- Department of Sports Kinanthropology, Faculty of Physical Education and Sport, Comenius University in Bratislava, Bratislava, Slovakia
- Aging and Lifestyle Diseases Research Center, Faculty of Physical Education and Sport, Comenius University in Bratislava, Bratislava, Slovakia
| | - Peter Sedliak
- Operations Department, Multiple Rocket Launcher System Battalion, Land Forces Headquarters, Armed Forces of the Slovak Republic, Rožňava, Slovakia; and
| | - Jani P Vaara
- Department of Leadership and Military Pedagogy, National Defence University, Helsinki, Finland
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24
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Lovalekar M, Hauret K, Roy T, Taylor K, Blacker SD, Newman P, Yanovich R, Fleischmann C, Nindl BC, Jones B, Canham-Chervak M. Musculoskeletal injuries in military personnel-Descriptive epidemiology, risk factor identification, and prevention. J Sci Med Sport 2021; 24:963-969. [PMID: 33824080 DOI: 10.1016/j.jsams.2021.03.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 03/15/2021] [Accepted: 03/24/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVES To provide an overall perspective on musculoskeletal injury (MSI) epidemiology, risk factors, and preventive strategies in military personnel. DESIGN Narrative review. METHODS The thematic session on MSIs in military personnel at the 5th International Congress on Soldiers' Physical Performance (ICSPP) included eight presentations on the descriptive epidemiology, risk factor identification, and prevention of MSIs in military personnel. Additional topics presented were bone anabolism, machine learning analysis, and the effects of non-steroidal anti-inflammatory drugs (NSAIDs) on MSIs. This narrative review focuses on the thematic session topics and includes identification of gaps in existing literature, as well as areas for future study. RESULTS MSIs cause significant morbidity among military personnel. Physical training and occupational tasks are leading causes of MSI limited duty days (LDDs) for the U.S. Army. Recent studies have shown that MSIs are associated with the use of NSAIDs. Bone MSIs are very common in training; new imaging technology such as high resolution peripheral quantitative computed tomography allows visualization of bone microarchitecture and has been used to assess new bone formation during military training. Physical activity monitoring and machine learning have important applications in monitoring and informing evidence-based solutions to prevent MSIs. CONCLUSIONS Despite many years of research, MSIs continue to have a high incidence among military personnel. Areas for future research include quantifying exposure when determining MSI risk; understanding associations between health-related components of physical fitness and MSI occurrence; and application of innovative imaging, physical activity monitoring and data analysis techniques for MSI prevention and return to duty.
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Affiliation(s)
- Mita Lovalekar
- Department of Sports Medicine and Nutrition, School of Health and Rehabilitation Sciences, University of Pittsburgh, USA.
| | - Keith Hauret
- U.S. Army Public Health Center, Aberdeen Proving Ground, USA
| | - Tanja Roy
- U.S. Army Research Institute of Environmental Medicine, USA
| | - Kathryn Taylor
- U.S. Army Research Institute of Environmental Medicine, USA
| | | | | | - Ran Yanovich
- Institute of Military Physiology, Israel Defense Forces Medical Corps, Israel; Department of Military Medicine, Hebrew University School of Medicine, Israel
| | - Chen Fleischmann
- Institute of Military Physiology, Israel Defense Forces Medical Corps, Israel; Department of Military Medicine, Hebrew University School of Medicine, Israel
| | - Bradley C Nindl
- Department of Sports Medicine and Nutrition, School of Health and Rehabilitation Sciences, University of Pittsburgh, USA
| | - Bruce Jones
- U.S. Army Public Health Center, Aberdeen Proving Ground, USA
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25
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Vine CAJ, Myers SD, Coakley SL, Blacker SD, Runswick OR. Transferability of Military-Specific Cognitive Research to Military Training and Operations. Front Psychol 2021; 12:604803. [PMID: 33679522 PMCID: PMC7930063 DOI: 10.3389/fpsyg.2021.604803] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 01/28/2021] [Indexed: 01/31/2023] Open
Affiliation(s)
- Christopher A J Vine
- Occupational Performance Research Group, Institute of Sport, University of Chichester, Chichester, United Kingdom
| | - Stephen D Myers
- Occupational Performance Research Group, Institute of Sport, University of Chichester, Chichester, United Kingdom
| | - Sarah L Coakley
- Occupational Performance Research Group, Institute of Sport, University of Chichester, Chichester, United Kingdom.,Faculty of Sport, Allied Health and Performance Science, St Mary's University, Twickenham, London, United Kingdom
| | - Sam D Blacker
- Occupational Performance Research Group, Institute of Sport, University of Chichester, Chichester, United Kingdom
| | - Oliver R Runswick
- Occupational Performance Research Group, Institute of Sport, University of Chichester, Chichester, United Kingdom.,Department of Psychology, Institute of Psychiatry, Psychology & Neuroscience, Kings College London, London, United Kingdom
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26
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Training-Induced Acute Neuromuscular Responses to Military Specific Test during a Six-Month Military Operation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 18:ijerph18010215. [PMID: 33396662 PMCID: PMC7796053 DOI: 10.3390/ijerph18010215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/21/2020] [Accepted: 12/25/2020] [Indexed: 12/18/2022]
Abstract
Limited data are available regarding strength and endurance training adaptations to occupational physical performance during deployment. This study assessed acute training-induced changes in neuromuscular (electromyography; EMG) and metabolic (blood lactate, BLa) responses during a high-intensity military simulation test (MST), performed in the beginning (PRE) and at the end (POST) of a six-month crisis-management operation. MST time shortened (145 ± 21 vs. 129 ± 16 s, -10 ± 7%, p < 0.001) during the operation. Normalized muscle activity increased from PRE to POST in the hamstring muscles by 87 ± 146% (116 ± 52 vs. 195 ± 139%EMGMVC, p < 0.001) and in the quadriceps by 54 ± 81% (26 ± 8 vs. 40 ± 20%EMGMVC, p < 0.001). In addition, higher acute BLa values were measured after MST during POST. Changes in BLa and EMG suggested an increased neural input and metabolic rate during POST MST, likely leading to faster performance times at the end of the operation. High EMG values throughout the different phases of MST suggested that despite the anaerobic nature of the test, the soldiers were able to maintain their voluntary muscle activation level until the end of the test. This indicates only limited neural fatigue during the two-minute high-intensity military specific performance. While learning effect may explain some part of the improvement in the MST performance times, combined strength and endurance training three times per week may improve neuromuscular performance in occupationally relevant tasks.
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27
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Stone BL, Heishman AD, Campbell JA. Effects of an Experimental vs. Traditional Military Training Program on 2-Mile Run Performance During the Army Physical Fitness Test. J Strength Cond Res 2020; 34:3431-3438. [PMID: 33235017 DOI: 10.1519/jsc.0000000000002176] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Stone, BL, Heishman, AD, and Campbell, JA. The effects of an experimental vs. traditional military training program on 2-mile run performance during the army physical fitness test. J Strength Cond Res 34(12): 3431-3438, 2020-The purpose of this study was to compare the effects of an experimental vs. traditional military run training on 2-mile run ability in the Army Reserve Officers' Training Corps cadets. Fifty college-aged cadets were randomly placed into 2 groups and trained for 4 weeks with either an experimental running program (EXP, n = 22) comprised rating of perceived exertion (RPE) intensity-specific, energy system-based intervals or with traditional military running program (TRA, n = 28) using a crossover study design. A 2-mile run assessment was performed just before the start, at the end of the first 4 weeks, and again after the second 4 weeks of training after crossover. The EXP program significantly decreased 2-mile run times (961.3 ± 155.8 seconds to 943.4 ± 140.2 seconds, p = 0.012, baseline to post 1), whereas the TRA group experienced a significant increase in run times (901.0 ± 79.2 vs. 913.9 ± 82.9 seconds) over the same training period. There was a moderate effect size (d = 0.61, p = 0.07) for the experimental run program to "reverse" the adverse effects of the traditional program within the 4-week training period (post 1 to post 2) after treatment crossover. Thus, for short-term training of military personnel, RPE intensity-specific running program comprising aerobic and anaerobic system development can enhance 2-mile run performance superior to a traditional program while reducing training volume (60 minutes per session vs. 43.2 minutes per session, respectively). Future research should extend the training period to determine efficacy of this training approach for long-term improvement of aerobic capacity and possible reduction of musculoskeletal injury.
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Affiliation(s)
- Brandon L Stone
- Sport and Military Performance Analytics Laboratory, Department of Health and Exercise Science, College of Arts and Sciences, The University of Oklahoma, Norman, Oklahoma
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28
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INFLUENCE OF LIMB DOMINANCE AND SHOULDER INJURY ON STRENGTH AND EXPLOSIVE FORCE IN US MARINES. Int J Sports Phys Ther 2020; 15:1129-1140. [PMID: 33344030 DOI: 10.26603/ijspt20201129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background The specialized roles of many military personnel require specific skills and high physical demands, placing unique stresses on the shoulders and increasing risk of injury. As normal dominant/nondominant shoulder asymmetries have been established in military personnel, bilateral strength comparisons must be understood in context of daily physical demands to monitor patients' progress or readiness to return to duty. Purpose This study aims to assess bilateral differences in strength and explosive force in United States Marines with a history of dominant or nondominant shoulder pathology. Study Design Cross-Sectional. Methods A total of 52 full-duty, male US Marines with a shoulder injury within the prior year participated. Bilateral isokinetic shoulder internal (IR) and external (ER) rotation strength, and peak force (Peak Force) and average rate of force production (Avg Rate) during an explosive push-up were collected. Dominant versus nondominant side data were independently examined within each group (DOM: dominant injury, NOND: nondominant injury). Comparison between DOM and NOND, as well as previously published CON (no history of shoulder injury) was also completed. Results NOND (n = 26) demonstrated significantly less IR (p < 0.001) and ER (p = 0.003) strength and Peak Force (p = 0.001) and Avg Rate (p = 0.047) on the injured side, while DOM (n = 26) demonstrated no bilateral differences in strength or push-up performance. Comparison between the three groups showed that NOND demonstrated significantly less ER strength than CON (p = 0.022). Conclusions Military personnel demonstrate asymmetric strength patterns likely due to increased demand of the dominant shoulder. US Marines with a history of injury to the nondominant shoulder performed differently than those with a dominant side injury, presenting with both strength and push-up asymmetries. They also demonstrated significant ER strength deficits compared to CON. Common clinical practice and previous literature often compare injured and uninjured limbs or injured individuals to healthy controls, but further distinction of dominant or nondominant side may provide more accurate information needed to develop targeted treatment strategies. Clinical Relevance Recognizing unique occupational demands and how patients may present differently with dominant versus nondominant side shoulder injuries are important considerations for ensuring accurate assessment and effective individualized rehabilitation. Level of Evidence 3.
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29
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Kilen A, Bay J, Bejder J, Breenfeldt Andersen A, Bonne T, Larsen P, Carlsen A, Egelund J, Nybo L, Vidiendal Olsen N, Aachmann-Andersen NJ, Løvind Andersen J, Nordsborg NB. Distribution of concurrent training sessions does not impact endurance adaptation. J Sci Med Sport 2020; 24:291-296. [PMID: 32998848 DOI: 10.1016/j.jsams.2020.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 08/14/2020] [Accepted: 09/09/2020] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Optimized concurrent training regimes are warranted in physical training of military-, law enforcement- and rescue-personnel. This study investigated if four 15-min endurance training sessions weekly improve aerobic capacity and performance more than one 60-min endurance session weekly during the initial phase of a Basic Military Training program. DESIGN A randomized training intervention study with functional and physiological tests before and after the intervention. METHODS Military conscripts (n=290) were randomly allocated to three groups completing 9 weeks training. Weekly training consisted of four endurance and four strength training sessions lasting 15min each ('Micro-training': MIC); one strength and one endurance session lasting 60min each ('Classical-training': CLA) or two 60min sessions of standard military training ('Control-training': CON). RESULTS Both 12-min (∼7-10%) and shuttle run performance (∼35-42%) improved (P≤0.001) similarly in all groups. Likewise, functional 2-min maximal repetition exercise capacity increased (P≤0.05) similarly in all groups (Lunges ∼17-24 %; PushUp ∼10-20%; AbdominalFlexions∼21-23%). Peak oxygen uptake changes depended on group (P≤0.05) with increases (P≤0.01) in MIC (7±7%, n=23) and CON (12±18%, n=17) and no changes in CLA. Maximal m. vastus lateralis citrate synthase activity decreased 14±26% (P≤0.001, n=18) in CLA. Likewise, maximal m. vastus lateralis 3-hydroxyacyl-CoA dehydrogenase activity decreased 8±17% in MIC (n=28) and 14±24% in CLA (n=18). CONCLUSIONS Four 15-min endurance training sessions weekly improves running performance and strength-endurance similarly to one 60min session. Peak oxygen uptake only increases with more than one endurance session weekly and leg muscle oxidative capacity appears reduced after basic military training.
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Affiliation(s)
- Anders Kilen
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark; Center for Military Physical Training, Danish Armed Forces Medical Command, Danish Defence, Denmark
| | - Jonathan Bay
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Jacob Bejder
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | | | - Thomas Bonne
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Pernille Larsen
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Andreas Carlsen
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Jon Egelund
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Lars Nybo
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | | | | | - Jesper Løvind Andersen
- Institute of Sports Medicine Copenhagen, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
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30
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Hoffman JR, Zuckerman A, Ram O, Sadot O, Cohen H. Changes in Hippocampal Androgen Receptor Density and Behavior in Sprague-Dawley Male Rats Exposed to a Low-Pressure Blast Wave. Brain Plast 2020; 5:135-145. [PMID: 33282677 PMCID: PMC7685673 DOI: 10.3233/bpl-200107] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective The purpose of this study was to examine the effect of exposure of a low-intensity blast wave on androgen receptor (AR) density in the hippocampus and the potential influence on behavioral and cognitive responses. Methods Sprague-Dawley rats were randomly assigned to either a blast exposed group (n = 27) or an unexposed (control) group (n = 10). Animals were treated identically, except that rats within the control group were not exposed to any of the characteristics of the blast wave. Behavior measures were conducted on day seven post-exposure. The rats were initially assessed in the elevated plus maze followed by the acoustic startle response paradigm. Spatial memory performance using the Morris water-maze test was assessed at 8-days post-exposure, for seven consecutive days. Following all behavioral tests AR immunofluorescence staining was performed in different hippocampal subregions. Results A significant elevation in anxiety index (p < 0.001) and impaired learning (p < 0.015) and spatial memory (p < 0.0015) were noted in exposed rats. In addition, a significant attenuation of the AR was noted in the CA1 (p = 0.006) and dentate gyrus (p = 0.031) subregions of the hippocampus in blast exposed animals. Correlational analyses revealed significant associations between AR and both anxiety index (r = -.36, p = 0.031) and memory (r = -0.38, p = 0.019). Conclusions The results of this study demonstrate that exposure to a low-pressure blast wave resulted in a decrease in AR density, which was associated with significant behavioral and cognitive changes.
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Affiliation(s)
- Jay R Hoffman
- Department of Physical Therapy, Ariel University, Ariel, Israel
| | - Amitai Zuckerman
- Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Faculty of Health Sciences, Division of Psychiatry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Omri Ram
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Oren Sadot
- Department of Mechanical Engineering, Ben-Gurion University, Israel
| | - Hagit Cohen
- Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Faculty of Health Sciences, Division of Psychiatry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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31
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Ojanen T, Kyröläinen H, Kozharskaya E, Häkkinen K. Changes in strength and power performance and serum hormone concentrations during 12 weeks of task-specific or strength training in conscripts. Physiol Rep 2020; 8:e14422. [PMID: 32378340 PMCID: PMC7202986 DOI: 10.14814/phy2.14422] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/19/2020] [Accepted: 03/23/2020] [Indexed: 11/24/2022] Open
Abstract
The purpose of this study was to investigate the effects of two different training programs on strength and power performance and serum hormone concentrations. A total of 104 male soldiers volunteered and took part in the 12‐week training period with baseline, mid‐, and post‐measurements of body composition, muscle strength, lower and upper body power, and blood samples to determine serum hormone concentrations. The mean (±SD) age of subjects was 20 ± 1 years, height 180 ± 6 cm and body mass 72.4 ± 8.8 kg. The subjects were divided into three different training groups: soldier task‐specific training (TS), strength training (ST), and control (CON). Each group had a total of 18 training sessions during the 12‐week study. In the muscle strength tests, most improvements could be observed in the TS and ST groups, especially, during the first weeks of the training period. Maximal isometric leg extension force increased significantly by 7.9 ± 12.2% (p < .05) in the TS and 7.1 ± 12.6% (p < .05) in the ST groups between the PRE and MID, as well as between the PRE and POST measurements by 8.1 ± 12.4% (p < .05) in TS and 12.3 ± 15.3% (p < .01) in ST. Serum TES concentration increased significantly in TS between the PRE and MID (16.8 ± 33.9%) and PRE and POST (11.2 ± 16.7%) measurements. Serum COR concentrations decreased in TS between the MID and POST (−7.8 ± 10.9%) and PRE and POST (−11.0 ± 14.3%) measurements. Although the differences observed were rather minor in magnitude, training in the TS and ST groups led to greater improvements in muscle strength and power performance compared to the training in the CON group. The development of strength and/or power of the lower and upper body was greater in the TS and ST groups, which is crucial for warfighter's performance. Therefore, it is important to have a structured resistance‐training program during military training to optimize the strength, power, and military‐specific performance.
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Affiliation(s)
- Tommi Ojanen
- Finnish Defence Research Agency, Finnish Defence Forces, Järvenpää, Finland
| | - Heikki Kyröläinen
- Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland.,National Defence University, Helsinki, Finland
| | - Elena Kozharskaya
- Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland
| | - Keijo Häkkinen
- Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland
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32
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Differences in Training Adaptations of Endurance Performance during Combined Strength and Endurance Training in a 6-Month Crisis Management Operation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17051688. [PMID: 32150971 PMCID: PMC7084630 DOI: 10.3390/ijerph17051688] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 12/21/2022]
Abstract
Decreases in aerobic fitness during military operations have been observed in several studies. Thus, differences in training adaptations during a 6-month crisis-management operation were compared by using the change in endurance performance as the outcome measure. Sixty-six male soldiers volunteered for the study, consisting of pre-post assessments of blood biomarkers, body composition, physical performance, and the military simulation test (MST) performance. Physical training volume was self-reported. After the follow-up, the data were divided based on individual changes in endurance performance. Endurance performance was improved in the high-responder group (HiR, n = 25) and maintained or decreased in the low-responder group (LoR n = 24). During the operation, the LoR group decreased while the HiR group increased their endurance training frequency from the pre-deployment level (Δ 28 ± 57% vs. -40 ± 62%, p = 0.004). Fat mass decreased (-7.6 ± 11.7% vs. 14.2 ± 20.4%, p < 0.001), and 1-min push-up (27.7 ± 21.9% vs. 11.7 ± 26.1%, p = 0.004) and MST performance improved (-13.6 ± 6.8% vs. -7.5 ± 6.5%, p = 0.006) more in the HiR group. No differences were observed in the changes of other physical performance test results or analyzed biomarkers. In conclusion, soldiers who were initially leaner and fitter in terms of lower body strength and power were more likely to decrease their aerobic fitness during the operation.
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Johnson CD, Eagle SR, Nindl BC, Lovalekar MT, Flanagan SD, Pepping GJ, Connaboy C. The effects of fatiguing exercise and load carriage on the perception and initiation of movement. Eur J Sport Sci 2020; 21:36-44. [PMID: 32013782 DOI: 10.1080/17461391.2020.1725137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Perceptual-motor coordination relies on the accurate coupling of the perceptual and movement systems. However, individuals must also be able to recalibrate to perturbations to perceptual and movement capabilities. We examined the effects of fatigue and load carriage on perceptual-motor coordination for a maximal leaping task. 23 participants completed an incremental fatigue protocol (light to fatiguing intensity stages) on two separate occasions (loaded/unloaded). At baseline and the end of every stage of the protocol, participants made perceptual judgments for the affordance of leaping. The accuracy of responses and reaction times were calculated and mean differences were assessed across exercise intensity and load carriage conditions. No interaction of exercise intensity and load carriage was detected, or main effect of load carriage. A main, quadratic effect of exercise intensity was detected on reaction times, with times decreasing through the moderate stage and increasing through post-fatigue. No effect of exercise/fatigue was detected on perceptual accuracy. The results indicate that exercise at high intensities through fatigue has a significant effect on perceptual-motor calibration. Contrastingly, in response to an action-scaled task, individuals can adequately recalibrate to increased load carriage.
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Affiliation(s)
- Caleb D Johnson
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Shawn R Eagle
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bradley C Nindl
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mita T Lovalekar
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Shawn D Flanagan
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Gert-Jan Pepping
- School of Exercise Science, Australian Catholic University, Banyo, Australia
| | - Christopher Connaboy
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA
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LaGoy AD, Johnson C, Allison KF, Flanagan SD, Lovalekar MT, Nagai T, Connaboy C. Compromised Dynamic Postural Stability Under Increased Load Carriage Magnitudes. J Appl Biomech 2020; 36:27-32. [PMID: 31914419 DOI: 10.1123/jab.2018-0473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 10/30/2019] [Accepted: 11/06/2019] [Indexed: 11/18/2022]
Abstract
Warfighter performance may be compromised through the impact of load carriage on dynamic postural stability. Men and women may experience this impact to differing extents due to postural stability differences. Therefore, the authors investigated the effect of load magnitude on dynamic postural stability in men and women during a landing and stabilization task. Dynamic postural stability of 32 subjects (16 women) was assessed during the unilateral landing of submaximal jumps under 3 load conditions: +0%, +20%, and +30% body weight. Dynamic postural stability was measured using the dynamic postural stability index, which is calculated from ground reaction force data sampled at 1200 Hz. Two-way mixed-measures analysis of variance compared dynamic postural stability index scores between sexes and loads. Dynamic postural stability index scores were significantly affected by load (P = .001) but not by sex or by the sex by load interaction (P > .05). Dynamic postural stability index scores increased between the 0% (0.359 ± 0.041), 20% (0.396 ± 0.034), and 30% (0.420 ± 0.028) body weight conditions. Increased load negatively affects dynamic postural stability with similar performance decrements displayed by men and women. Men and women warfighters may experience similar performance decrements under load carriage conditions of similar relative magnitudes.
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Larsson J, Dencker M, Olsson MC, Bremander A. Development and application of a questionnaire to self-rate physical work demands for ground combat soldiers. APPLIED ERGONOMICS 2020; 83:103002. [PMID: 31747636 DOI: 10.1016/j.apergo.2019.103002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 10/28/2019] [Accepted: 11/12/2019] [Indexed: 06/10/2023]
Abstract
PURPOSE The aim of the present study was to identify the most physically demanding work tasks for Swedish ground combat soldiers through the development and application of a questionnaire survey. This is the first in a series of studies aiming to describe the development process and validation of physical selection standards in the Swedish armed forces. METHODS Based on procedural documentation, combat manuals and job analyses, a questionnaire was developed that defined and rated the perceived physical strain of 30 work tasks for ground combat soldiers. To assess validity, an expert focus group was used and psychometric analysis performed. The questionnaire was then distributed to 231 ground combat soldiers, of whom 165 responded (71%). RESULTS The questionnaire was validated in three steps to achieve face and content validity, and internal consistency was acceptable (Chronbach's alpha ≥0.95). Of the 30 work tasks included in the survey, transport of wounded was rated as the most demanding task for both aerobic capacity and strength. Other highly demanding tasks for aerobic capacity included combat movement (low/high crawl), dismounted attack in close country, urban and rough terrain and carrying heavy loads. There were no gender differences for either aerobic or strength demands in the top five most challenging tasks based on proportions. CONCLUSIONS This study identified the most physically demanding tasks performed in the Swedish ground combat forces. Almost all the physically demanding tasks found in the present study contain elements of lifting and carrying, which require muscular strength and muscular endurance, with no gender differences.
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Affiliation(s)
- Jonas Larsson
- Department of Medical Imaging and Physiology, Skåne University Hospital Department of Translational Medicine, Lund University, Sweden; School of Business, Engineering and Science, Rydberg Laboratory for Applied Science, Halmstad University, Sweden; Swedish Armed Forces, Eksjö, Sweden.
| | - Magnus Dencker
- Department of Medical Imaging and Physiology, Skåne University Hospital Department of Translational Medicine, Lund University, Sweden
| | - M Charlotte Olsson
- School of Business, Engineering and Science, Rydberg Laboratory for Applied Science, Halmstad University, Sweden
| | - Ann Bremander
- School of Business, Engineering and Science, Rydberg Laboratory for Applied Science, Halmstad University, Sweden; Department of Clinical Sciences, Lund, Section of Rheumatology, Lund University, Sweden
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Parsons IT, Stacey MJ, Woods DR. Heat Adaptation in Military Personnel: Mitigating Risk, Maximizing Performance. Front Physiol 2019; 10:1485. [PMID: 31920694 PMCID: PMC6928107 DOI: 10.3389/fphys.2019.01485] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/21/2019] [Indexed: 12/22/2022] Open
Abstract
The study of heat adaptation in military personnel offers generalizable insights into a variety of sporting, recreational and occupational populations. Conversely, certain characteristics of military employment have few parallels in civilian life, such as the imperative to achieve mission objectives during deployed operations, the opportunity to undergo training and selection for elite units or the requirement to fulfill essential duties under prolonged thermal stress. In such settings, achieving peak individual performance can be critical to organizational success. Short-notice deployment to a hot operational or training environment, exposure to high intensity exercise and undertaking ceremonial duties during extreme weather may challenge the ability to protect personnel from excessive thermal strain, especially where heat adaptation is incomplete. Graded and progressive acclimatization can reduce morbidity substantially and impact on mortality rates, yet individual variation in adaptation has the potential to undermine empirical approaches. Incapacity under heat stress can present the military with medical, occupational and logistic challenges requiring dynamic risk stratification during initial and subsequent heat stress. Using data from large studies of military personnel observing traditional and more contemporary acclimatization practices, this review article (1) characterizes the physical challenges that military training and deployed operations present (2) considers how heat adaptation has been used to augment military performance under thermal stress and (3) identifies potential solutions to optimize the risk-performance paradigm, including those with broader relevance to other populations exposed to heat stress.
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Affiliation(s)
- Iain T. Parsons
- Academic Department of Military Medicine, Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King’s College London, London, United Kingdom
| | - Michael J. Stacey
- Academic Department of Military Medicine, Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Department of Diabetes and Endocrinology, Imperial College Healthcare NHS Trust, London, United Kingdom
| | - David R. Woods
- Academic Department of Military Medicine, Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Department of Sport and Exercise Endocrinology, Carnegie Research Institute, Leeds Beckett University, Leeds, United Kingdom
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Expanding the injury definition: evidence for the need to include musculoskeletal conditions. Public Health 2019; 169:69-75. [DOI: 10.1016/j.puhe.2019.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 12/12/2018] [Accepted: 01/03/2019] [Indexed: 11/18/2022]
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Johnson CD, Nijst BKJF, Eagle SR, Kessels MWM, Lovalekar MT, Krajewski KT, Flanagan SD, Nindl BC, Connaboy C. Evaluation of Shoulder Strength and Kinematics as Risk Factors for Shoulder Injury in United States Special Forces Personnel. Orthop J Sports Med 2019; 7:2325967119831272. [PMID: 30891463 PMCID: PMC6416681 DOI: 10.1177/2325967119831272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Musculoskeletal injuries at the shoulder are highly prevalent and place a large burden on United States Special Forces personnel. Literature is lacking regarding the risk factors for these types of injuries. Purpose/Hypothesis The purpose of this study was to evaluate the association of shoulder strength and kinematic characteristics, which have shown retrospective associations with shoulder conditions/injuries, with prospectively collected shoulder injuries. We hypothesized that lower strength and abnormal kinematics would be predictive of future shoulder injury. Study Design Case-control study; Level of evidence, 3. Methods A total of 140 male Special Forces operators underwent a musculoskeletal evaluation of the shoulder that included a scapular kinematic assessment during a humeral elevation task and isokinetic strength testing of the scapular protractors/retractors, external/internal rotators, and elevators of the shoulder. From strength assessments, ipsilateral strength ratios and bilateral strength asymmetries were also calculated. Musculoskeletal injuries of the shoulder were collected prospectively by use of medical chart reviews at 365 days following the evaluation. Separate generalized estimating equations (GEEs) and simple logistic regressions were used to analyze the association between baseline predictors and development of shoulder injury. Results Results of the GEEs showed no significant prediction of shoulder injury by shoulder strength (odds ratio [OR], 1.00-1.03), ipsilateral strength ratios (OR, 0.43-2.12), or scapular kinematics (OR, 0.99-1.01). Logistic regression indicated that none of the bilateral asymmetries were significantly predictive of shoulder injury (OR, 1.00-1.04). Conclusion The results indicate that shoulder strength and kinematic characteristics are not risk factors for shoulder injury in the Special Forces population. These findings are in opposition to the general findings of previous research using a retrospective analysis.
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Affiliation(s)
- Caleb D Johnson
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Branco K J F Nijst
- Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands
| | - Shawn R Eagle
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Marijn W M Kessels
- Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands
| | - Mita T Lovalekar
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kellen T Krajewski
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Shawn D Flanagan
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Bradley C Nindl
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Christopher Connaboy
- Neuromuscular Research Laboratory, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Pearce SC, Coia HG, Karl JP, Pantoja-Feliciano IG, Zachos NC, Racicot K. Intestinal in vitro and ex vivo Models to Study Host-Microbiome Interactions and Acute Stressors. Front Physiol 2018; 9:1584. [PMID: 30483150 PMCID: PMC6240795 DOI: 10.3389/fphys.2018.01584] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/23/2018] [Indexed: 12/16/2022] Open
Abstract
The gut microbiome is extremely important for maintaining homeostasis with host intestinal epithelial, neuronal, and immune cells and this host-microbe interaction is critical during times of stress or disease. Environmental, nutritional, and cognitive stress are just a few factors known to influence the gut microbiota and are thought to induce microbial dysbiosis. Research on this bidirectional relationship as it pertains to health and disease is extensive and rapidly expanding in both in vivo and in vitro/ex vivo models. However, far less work has been devoted to studying effects of host-microbe interactions on acute stressors and performance, the underlying mechanisms, and the modulatory effects of different stressors on both the host and the microbiome. Additionally, the use of in vitro/ex vivo models to study the gut microbiome and human performance has not been researched extensively nor reviewed. Therefore, this review aims to examine current evidence concerning the current status of in vitro and ex vivo host models, the impact of acute stressors on gut physiology/microbiota as well as potential impacts on human performance and how we can parlay this information for DoD relevance as well as the broader scientific community. Models reviewed include widely utilized intestinal cell models from human and animal models that have been applied in the past for stress or microbiology research as well as ex vivo organ/tissue culture models and new innovative models including organ-on-a-chip and co-culture models.
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Affiliation(s)
- Sarah C Pearce
- Performance Nutrition Team, Combat Feeding Directorate, Natick Soldier Research, Development and Engineering Center, Natick, MA, United States
| | - Heidi G Coia
- National Research Council, The National Academies of Sciences, Engineering, and Medicine, Washington, DC, United States.,711th Human Performance Wing, Airforce Research Laboratory, Airman Systems Directorate, Human-Centered ISR Division, Molecular Mechanisms Branch, Wright-Patterson Air Force Base, Dayton, OH, United States
| | - J P Karl
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States
| | - Ida G Pantoja-Feliciano
- Soldier Protection and Optimization Directorate, Natick Soldier Research, Development and Engineering Center, Natick, MA, United States
| | - Nicholas C Zachos
- Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Kenneth Racicot
- Performance Nutrition Team, Combat Feeding Directorate, Natick Soldier Research, Development and Engineering Center, Natick, MA, United States
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Perspectives on resilience for military readiness and preparedness: Report of an international military physiology roundtable. J Sci Med Sport 2018; 21:1116-1124. [DOI: 10.1016/j.jsams.2018.05.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 04/23/2018] [Accepted: 05/08/2018] [Indexed: 11/19/2022]
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Ojanen T, Jalanko P, Kyröläinen H. Physical fitness, hormonal, and immunological responses during prolonged military field training. Physiol Rep 2018; 6:e13850. [PMID: 30187684 PMCID: PMC6125608 DOI: 10.14814/phy2.13850] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/06/2018] [Accepted: 08/10/2018] [Indexed: 11/24/2022] Open
Abstract
Physical fitness is crucial to warfighters' performance in the battlefield. Previous studies have shown negative changes in their hormonal and neuromuscular responses induced by military field training (MFT). The purpose of this study was to investigate the changes in hormonal and immunological values and body composition during a prolonged MFT and to find out how warfighters' physical condition influences these changes. Conscripts (n = 49, age 20 ± 1 years, height 179 ± 9 cm, body mass 73.8 ± 7.8 kg, fat 12.6 ± 3.7% and BMI 23 kg/m²) were measured before, during, after MFT, and after a 4-day recovery period. Serum insulin-like growth factor-1 (IGF-1), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) concentrations, creatine kinase (CK) activity and leptin concentration were analyzed as well as body composition throughout MFT. Neuromuscular performance was assessed via lower and upper body muscle endurance at the beginning of the study. During MFT, there was a significant decrease (P < 0.05) in body mass (2.3%), fat mass (7.7%) and in muscle mass (2.2%), but all of these values recovered to PRE-levels after the recovery period. Serum IGF-1 (22%) and leptin decreased (66%) while CK increased (88%) significantly (P < 0.05) during MFT but recovered at the end of MFT. Upper body dynamic and trunk isometric muscular endurance had a positive correlation (r = 0.37. P < 0.05) with the change in IGF-1 during MFT and a negative correlation with the changes in CK (-0.34, P < 0.05). The results show that there were negative changes in conscript's body composition and hormonal and immunological values during the prolonged MFT. These changes suggest that the physiological stress was high during MFT. High levels of upper body and trunk muscular strength were negatively correlated with warfighters' physiological effects and should therefore be developed prior to actual deployment to reduce the physical decline experienced during prolonged MFTs.
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Affiliation(s)
- Tommi Ojanen
- Finnish Defence Research AgencyFinnish Defence ForcesJärvenpääFinland
| | - Petri Jalanko
- Biology of Physical ActivityUniversity of JyväskyläJyväskyläFinland
| | - Heikki Kyröläinen
- Biology of Physical ActivityUniversity of JyväskyläJyväskyläFinland
- National Defence UniversityHelsinkiFinland
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Threshold of Energy Deficit and Lower-Body Performance Declines in Military Personnel: A Meta-Regression. Sports Med 2018; 48:2169-2178. [DOI: 10.1007/s40279-018-0945-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Lovalekar M, Sharp MA, Billing DC, Drain JR, Nindl BC, Zambraski EJ. International consensus on military research priorities and gaps - Survey results from the 4th International Congress on Soldiers' Physical Performance. J Sci Med Sport 2018; 21:1125-1130. [PMID: 29910153 DOI: 10.1016/j.jsams.2018.05.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/25/2018] [Accepted: 05/29/2018] [Indexed: 11/20/2022]
Abstract
OBJECTIVES The objectives of this study were to identify perceived priorities related to military personnel's health and physical performance, among attendees at the 4th International Congress on Soldiers' Physical Performance (ICSPP), and to determine if perceived priorities had changed between the 3rd ICSPP survey held in 2014 and the 4th ICSPP survey held in 2017. DESIGN Electronic survey. METHODS Respondents were asked to grade priority areas on a Likert scale, and average ratings were used to rank priority areas. Responses to free text questions were analyzed qualitatively. Responses to the 4th ICSPP survey were described and compared to responses to the 3rd ICSPP survey. RESULTS The 4th ICSPP survey respondents were a diverse group (40.6% military, 58.9% civilian). The two most important priority areas identified were physical demands in operational environments (mean score=4.41/5) and measuring physical performance/fitness (4.38/5), which were also the top two areas in the 3rd ICSPP survey. There was remarkable overlap in the rankings of priority areas between the two surveys. Sleep and nutrition were emerging priority areas and were perceived as relatively more important in the 4th ICSPP survey compared to the 3rd ICSPP survey. The greatest perceived emerging threat was resilience/psychological fitness of recruits (4.16/5). Physiological status monitoring (2.79/4) was identified as the most important technology. CONCLUSIONS Despite the diverse backgrounds of the respondents, there was a clear continuing consensus about perceived important priority areas influencing military personnel's health and physical performance. Soldier resiliency and assessment of physiological status were research topics identified as top priorities.
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Affiliation(s)
- Mita Lovalekar
- Department of Sports Medicine and Nutrition, School of Health and Rehabilitation Sciences, University of Pittsburgh, USA.
| | | | | | - Jace R Drain
- Land Division, Defense Science & Technology Group, Australia
| | - Bradley C Nindl
- Department of Sports Medicine and Nutrition, School of Health and Rehabilitation Sciences, University of Pittsburgh, USA
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McLellan TM, Riviere LA, Williams KW, McGurk D, Lieberman HR. Caffeine and energy drink use by combat arms soldiers in Afghanistan as a countermeasure for sleep loss and high operational demands. Nutr Neurosci 2018. [DOI: 10.1080/1028415x.2018.1443996] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
| | - Lyndon A. Riviere
- Military Psychiatry Branch, Center for Military Psychiatry and Neurosciences Research, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | | | - Dennis McGurk
- United States Army Medical Research and Materiel Command, Ft Detrick, MD, USA
| | - Harris R. Lieberman
- Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, MA, USA
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Eagle SR, Connaboy C, Nindl BC, Allison KF. Significantly Increased Odds of Reporting Previous Shoulder Injuries in Female Marines Based on Larger Magnitude Shoulder Rotator Bilateral Strength Differences. Orthop J Sports Med 2018; 6:2325967118756283. [PMID: 29497623 PMCID: PMC5824909 DOI: 10.1177/2325967118756283] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Background: Musculoskeletal injuries to the extremities are a primary concern for the United States (US) military. One possible injury risk factor in this population is side-to-side strength imbalance. Purpose: To examine the odds of reporting a previous shoulder injury in US Marine Corps Ground Combat Element Integrated Task Force volunteers based on side-to-side strength differences in isokinetic shoulder strength. Study Design: Cohort study; Level of evidence, 3. Methods: Male (n = 219) and female (n = 91) Marines were included in this analysis. Peak torque values from 5 shoulder internal/external rotation repetitions were averaged and normalized to body weight. The difference in side-to-side strength measurements was calculated as the absolute value of the limb difference divided by the mean peak torque of the dominant limb. Participants were placed into groups based on the magnitude of these differences: <10%, 10% to 20%, and >20%. Odds ratios (ORs) and 95% CIs were calculated. Results: When separated by sex, 13.2% of men reported an injury, while 5.5% of women reported an injury. Female Marines with >20% internal rotation side-to-side strength differences demonstrated increased odds of reporting a previous shoulder injury compared with female Marines with <10% strength differences (OR, 15.4; 95% CI, 1.4-167.2; P = .03 ) and female Marines with 10% to 20% strength differences (OR, 13.9; 95% CI, 1.3-151.2; P = .04). No significant ORs were demonstrated in male Marines. Conclusion: Marines with larger magnitude internal rotation strength differences demonstrated increased odds of reporting a previous shoulder injury compared with those with lesser magnitude differences. Additionally, female sex appears to drastically affect the increased odds of reporting shoulder injuries (OR, 13.9-15.4) with larger magnitude differences (ie, >20%) compared with those with lesser magnitude differences (ie, <10% and 10%-20%). The retrospective cohort design of this study cannot delineate cause and effect but establishes a relationship between female Marines and greater odds of larger magnitude strength differences after returning from an injury.
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Affiliation(s)
- Shawn R Eagle
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Chris Connaboy
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Bradley C Nindl
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Katelyn F Allison
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Wang ZG, Ding MC, Yin X, Zhao Y, Hu F, Ma JZ. Influence of 15 km moderate or high-intensity interval military load carriage activity on postural stability. COGENT MEDICINE 2017. [DOI: 10.1080/2331205x.2017.1408926] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- Zeng Gang Wang
- The Research Center of Military Physical Adaptation Training, The Lab of Military Physical Conditioning and Motor Function Assessment, The PLA Army Engineering University, 60 Shuang Long Jie Road, Nanjing, Jiangsu 211101, China
| | - Ming Chao Ding
- The Research Center of Military Physical Adaptation Training, The Lab of Military Physical Conditioning and Motor Function Assessment, The PLA Army Engineering University, 60 Shuang Long Jie Road, Nanjing, Jiangsu 211101, China
| | - Xin Yin
- Department of Exercise and Heath, Nanjing Sports Institute, 8 Ling Gu Si Road, Nanjing, Jiangsu 210014, China
| | - Yan Zhao
- Department of Exercise and Heath, Nanjing Sports Institute, 8 Ling Gu Si Road, Nanjing, Jiangsu 210014, China
| | - Fei Hu
- Department of Exercise and Heath, Nanjing Sports Institute, 8 Ling Gu Si Road, Nanjing, Jiangsu 210014, China
| | - Ji Zheng Ma
- The Research Center of Military Physical Adaptation Training, The Lab of Military Physical Conditioning and Motor Function Assessment, The PLA Army Engineering University, 60 Shuang Long Jie Road, Nanjing, Jiangsu 211101, China
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Epidemiology of musculoskeletal injuries sustained by Naval Special Forces Operators and students. J Sci Med Sport 2017; 20 Suppl 4:S51-S56. [DOI: 10.1016/j.jsams.2017.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 08/29/2017] [Accepted: 09/04/2017] [Indexed: 11/22/2022]
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Military human performance optimization and injury prevention: Strategies for the 21st century warfighter. J Sci Med Sport 2017; 20 Suppl 4:S1-S2. [DOI: 10.1016/j.jsams.2017.10.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Drain JR, Groeller H, Burley SD, Nindl BC. Hormonal response patterns are differentially influenced by physical conditioning programs during basic military training. J Sci Med Sport 2017; 20 Suppl 4:S98-S103. [PMID: 28927970 DOI: 10.1016/j.jsams.2017.08.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 08/23/2017] [Accepted: 08/29/2017] [Indexed: 11/16/2022]
Abstract
OBJECTIVES Compare traditional military physical training and more contemporary physical training on catabolic and anabolic hormones and body composition in recruits undertaking basic military training (BMT). DESIGN A prospective cross-sectional study design. METHODS Two recruit intakes were assessed over the 12-week Australian Army BMT course. The control group (CON) comprised 40 recruits (26M/14F) and the experimental group (EXP) comprised 35 recruits (25M/10F). Hormone concentrations (IGF-I, testosterone, cortisol, SHBG) and body composition were assessed at weeks 1 and 12. The EXP group undertook a higher-load/intensity physical training regimen, while CON undertook the extant physical training program which focused on cardiovascular and muscular endurance. Total physical activity within physical training sessions was assessed during weeks 2, 6 and 9. RESULTS There was a significant group×time interaction (p<0.01) for IGF-I and cortisol, and main effects over time (p<0.01) for IGF-I, cortisol and SHBG. There were main effects for time (p<0.05) for lean and fat mass, and these changes were associated (p<0.05) with altered hormone concentrations. Physical activity levels were approximately 50% lower in EXP than CON during physical training sessions. CONCLUSIONS This is the first study to report a differential hormone response to contrasting physical conditioning regimen during BMT. The results indicate that the recruits who completed the EXP physical training regimen had an attenuated stress profile. This is an important observation, as any enhancement of recruit training outcomes are critical for Army noting that fundamentally, organisational capability is reliant upon the physical capability of its personnel.
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Affiliation(s)
- Jace R Drain
- Defence Science and Technology Group, Australia.
| | - Herbert Groeller
- Centre for Human and Applied Physiology, University of Wollongong, Australia
| | - Simon D Burley
- Centre for Human and Applied Physiology, University of Wollongong, Australia
| | - Bradley C Nindl
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, University of Pittsburgh, USA
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Nindl BC, Eagle SR, Frykman PN, Palmer C, Lammi E, Reynolds K, Allison K, Harman E. Functional physical training improves women's military occupational performance. J Sci Med Sport 2017; 20 Suppl 4:S91-S97. [PMID: 28986086 DOI: 10.1016/j.jsams.2017.07.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/21/2017] [Accepted: 07/05/2017] [Indexed: 10/19/2022]
Abstract
The U.S. Armed Forces have recently approved full integration of women into combat roles. Physical fitness demands for executing Military Occupational Specialties (MOS) are substantial; thus lifting and load carriage capability improvements are desirable. OBJECTIVES To determine if a specially-designed physical conditioning program could lessen the gap between the performance of male and female Soldiers in lifting and load carriage and thereby enable women to meet the requirements of most, if not all, Army MOSs. METHODS Forty women participated in a 24-week physical training program, which included resistance training, long-distance running, backpacking, and specialized drills. Pre- and post-tests of occupational and physical performance measures were conducted before and after training. Repeated measures analysis of variance were used to determine statistically significant differences among the pre-, mid- and posttests. RESULTS Women increased maximal occupational lifting strength 12-20 kg, added 9-34 repetitions in lifting endurance, increased 0.23 m in jumping performance, added 46 repetitions in local muscular endurance, and decreased load carriage for time by 3.7-8.6 min. Women scored within 82-94% of untrained male scores for aerobic capacity and muscular endurance after training. CONCLUSION Women's ability to perform physically-demanding military occupational tasks was significantly improved following 6 months of concurrent training, with emphasis on load carriage and lifting. The percentage of women that qualified for current "heavy" and "very heavy" MOSs was initially 24%, but increased to 78% after training. A resistance training program of 6+ months can adequately prepare women for "heavy" to "very heavy" MOS's.
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Affiliation(s)
- Bradley C Nindl
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, School of Health and Rehabilitation Sciences, University of Pittsburgh, United States.
| | - Shawn R Eagle
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, School of Health and Rehabilitation Sciences, University of Pittsburgh, United States
| | - Peter N Frykman
- Military Performance Division, U.S. Army Research Institute of Environmental Medicine, United States
| | - Christopher Palmer
- Military Performance Division, U.S. Army Research Institute of Environmental Medicine, United States
| | - Eric Lammi
- Military Performance Division, U.S. Army Research Institute of Environmental Medicine, United States
| | - Katy Reynolds
- Military Performance Division, U.S. Army Research Institute of Environmental Medicine, United States
| | - Katelyn Allison
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, School of Health and Rehabilitation Sciences, University of Pittsburgh, United States
| | - Everett Harman
- Military Performance Division, U.S. Army Research Institute of Environmental Medicine, United States
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