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Johnson CD, Sara LK, Bradach MM, Zeppetelli DJ, Dæhlin TE, Mullineaux DR, Foulis SA, Hughes JM, Davis IS. Sex- and age-related differences in kinetics and tibial accelerations during military-relevant movement tasks in U.S. Army trainees. Eur J Sport Sci 2024; 24:740-749. [PMID: 38874992 DOI: 10.1002/ejsc.12091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 02/08/2024] [Accepted: 02/09/2024] [Indexed: 06/15/2024]
Abstract
Lower extremity injuries are prevalent in military trainees, especially in female and older trainees. Modifiable factors that lead to higher injury risk in these subgroups are not clear. The purpose of this study was to identify whether external loading variables during military-relevant tasks differ by age and sex in U.S. Army trainees. Data was collected on 915 trainees in the first week of Basic Combat Training. Participants performed running and ruck marching (walking with 18.1 kg pack) on a treadmill, as well as double-/single-leg drop landings. Variables included: vertical force loading rates, vertical stiffness, first peak vertical forces, peak vertical and resultant tibial accelerations. Comparisons were made between sexes and age groups (young, ≤19 years; middle, 20-24 years; older, ≥25 years). Significant main effects of sex were found, with females showing higher vertical loading rates during ruck marching, and peak tibial accelerations during running and ruck marching (p ≤ 0.03). Males showed higher vertical stiffness during running and peak vertical tibial accelerations during drop landings (p < 0.01). A main effect of age was found for vertical loading rates during running (p = 0.03), however no significant pairwise differences were found between age groups. These findings suggest that higher external loading may contribute to higher overall injury rates in female trainees. Further, higher stiffness during running may contribute to specific injuries, such as Achilles Tendinopathy, that are more prevalent in males. The lack of differences between age groups suggests that other factors contribute more to higher injury rates in older trainees.
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Affiliation(s)
- Caleb D Johnson
- Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Lauren K Sara
- Spaulding National Running Center, Spaulding Rehabilitation Hospital, Cambridge, Massachusetts, USA
- College of Health and Rehabilitation Sciences, Boston University, Boston, Massachusetts, USA
| | - Molly M Bradach
- Spaulding National Running Center, Spaulding Rehabilitation Hospital, Cambridge, Massachusetts, USA
| | - David J Zeppetelli
- Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Torstein E Dæhlin
- School of Physical Therapy and Rehabilitation Sciences, University of South Florida, Tampa, Florida, USA
| | | | - Stephen A Foulis
- Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Julie M Hughes
- Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Irene S Davis
- School of Physical Therapy and Rehabilitation Sciences, University of South Florida, Tampa, Florida, USA
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Faghy MA, Shei R, Armstrong NCD, White M, Lomax M. Physiological impact of load carriage exercise: Current understanding and future research directions. Physiol Rep 2022; 10:e15502. [PMID: 36324291 PMCID: PMC9630762 DOI: 10.14814/phy2.15502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 09/18/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022] Open
Abstract
Load carriage (LC) refers to the use of personal protective equipment (PPE) and/or load-bearing apparatus that is mostly worn over the thoracic cavity. A commonplace task across various physically demanding occupational groups, the mass being carried during LC duties can approach the wearer's body mass. When compared to unloaded exercise, LC imposes additional physiological stress that negatively impacts the respiratory system by restricting chest wall movement and altering ventilatory mechanics as well as circulatory responses. Consequently, LC activities accelerate the development of fatigue in the respiratory muscles and reduce exercise performance in occupational tasks. Therefore, understanding the implications of LC and the effects specific factors have on physiological capacities during LC activity are important to the implementation of effective mitigation strategies to ameliorate the detrimental effects of thoracic LC. Accordingly, this review highlights the current physiological understanding of LC activities and outlines the knowledge and efficacy of current interventions and research that have attempted to improve LC performance, whilst also highlighting pertinent knowledge gaps that must be explored via future research activities.
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Affiliation(s)
- Mark A. Faghy
- Biomedical Research Theme, School of Human SciencesUniversity of DerbyDerbyUK
| | - Ren‐Jay Shei
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Nicola C. D. Armstrong
- Defence Science and Technology LaboratorySalisburyUK
- Extreme Environments Laboratory, School of Sport, Health and Exercise ScienceUniversity of PortsmouthPortsmouthUK
| | - Mark White
- Rocky Mountain University of Health ProfessionsProvoUtahUSA
| | - Mitch Lomax
- Extreme Environments Laboratory, School of Sport, Health and Exercise ScienceUniversity of PortsmouthPortsmouthUK
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LaGoy AD, Sinnott AM, Eagle SR, Beckner ME, Conkright WR, Proessl F, Williams J, Dretsch MN, Flanagan SD, Nindl BC, Lovalekar M, Germain A, Ferrarelli F, Connaboy C. Combined effects of time-of-day and simulated military operational stress on perception-action coupling performance. Chronobiol Int 2022; 39:1485-1497. [PMID: 36131615 DOI: 10.1080/07420528.2022.2125405] [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: 11/03/2022]
Abstract
Perception-action coupling, the ability to 'read and react' to the environment, is essential for military personnel to operate within complex and unpredictable environments. Exposure to military operational stressors (e.g., caloric restriction, sleep loss, physical exertion), including around-the-clock operations, may compromise perception-action coupling, thereby impacting performance and safety. We examined the combined effects of simulated military operational stress (SMOS) and time-of-day on perception-action coupling. Fifty-seven active duty and reservist military personnel (45 M; 26.4 ± 5.6 years) completed a 5-day SMOS protocol that included two consecutive days of caloric restriction, and sleep restriction, and disruption. Participants completed a tablet-based perception-action coupling task (PACT) that involves perceiving whether virtual balls fit through virtual apertures. Familiarization occurred on day 0. Eight trials across day 1 (18:00, 22:00), 2 (04:00, 18:00, 22:00) and 3 (04:00, 18:00, 22:00) were analyzed. Mixed models were run to examine the interactive and main effects of day, and time-of-day on PACT response speed and accuracy outcomes. PACT response speed and accuracy outcomes improved at 18:00 and 22:00, whereas performance at 04:00 deteriorated across days. Perception-action coupling performance was resilient to SMOS, except in the early morning when the circadian drive for sleep is high, and the effects of sleep loss are more prominent.
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Affiliation(s)
- Alice D LaGoy
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Aaron M Sinnott
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Shawn R Eagle
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Meaghan E Beckner
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - William R Conkright
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Felix Proessl
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Justin Williams
- Sleep and Behavioral Neuroscience Center, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Michael N Dretsch
- US Army Medical Research Directorate-West, Walter Reed Army Institute for Research, Joint Base Lewis-McCord, Washington, USA
| | - Shawn D Flanagan
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Bradley C Nindl
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Mita Lovalekar
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Anne Germain
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Fabio Ferrarelli
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Christopher Connaboy
- Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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