• All authors must approve submission of the abstract.
• All abstracts must abide by local ethical rules regarding the use of animal or human participants and their data.
• Abstracts do not need to declare potential conflict of interests, but conflicts of interest must be declared in the presentation or poster.

• The abstract must be submitted in English.
• The presenting author to be the first named author on the abstract.
• Notification will be emailed only to the presenting author.
• Abstracts must not exceed 400 words (excluding the title, authors, and affiliations).
• The use of references should be kept to an absolute minimum and avoided where possible, but if used should be cited at the end of the abstract and included in the 400-word count.
• Only those abstracts formally accepted will be published in the Congress Proceedings. Should your Reviewers require you to make changes you will be invited to submit amendments prior to acceptance.
• Abstracts should not contain any tables or figures.
• The use of abbreviations and acronyms should be kept to an absolute minimum and avoided where possible.

• The abstract should be organised under the following headings: Title, Purpose, Methods, Results, Conclusions, and Military Impact. An example abstract is presented below.

  Title: A brief title to include study population and study design where possible.

  Purpose: A concise statement of the research problem, hypothesis, or objective.

  Methods: The experimental methods used including the statistical analyses.

  Results: Include all supporting data. Abstracts that lack experimental data or include data statements "to be discussed" or "to be presented" may be rejected. Data should be presented as SI units.

  Conclusions: A discussion of the findings based on the reported results.

  Military Impact: Describe how the research impacts Defence.

SUBMIT ABSTRACT

Authors will need to select two of the following themes that best fit their abstract:

• Environmental Stressors, Exposures, and Injuries
• Data Analytics and Predictive Modelling
• Physical Training
• Musculoskeletal Injury and Physiology
• Nutrition and Metabolism
• Futures Science and Technology
• Human Augmentation
• Trial Design, Methods, Conduct, and Reporting
• Female Physiology
• Physical Performance
• Cognitive Performance
• Psychological Resilience and Performance
• Health and Wellbeing
• Mental Health
• Epidemiology
• Human Machine Teaming
• Neurobiology

Abstracts may be submitted for one of the following presentation types:

• Oral Presentation: A 10 min presentation by the lead author with 5 min for questions.
• Oral Poster: A 5 min presentation by the lead author with 5 min for questions.
• Poster Presentation: Poster display without oral presentation.

Authors can state their preferred form of presentation, but the final decision will be made by the committee. Format guidelines for presentations will be issued with the decision letter.

Title: The effect of sex and protein supplementation on bone metabolism during a 36-hour military field exercise in energy deficit

Presenting author’s name: John Smith, British Army

Presenting author’s email address: john.smith100@mod.gov.uk.

Author names and affiliations: Doe, Jane, British Army; Body, Nicola E, British Army.

ABSTRACT MAIN BODY

Purpose: Acute periods of low energy availability during military field exercise can decrease circulating markers of bone formation, but the sex difference in this bone metabolic response is poorly understood. Protein plays a structural role in the bone matrix, and protein feeding increases intestinal calcium absorption and may attenuate changes in concentrations of anabolic and metabolic hormones during energy deficit. This study investigated sex differences in, and the effect of supplementary protein on, bone metabolism during a 36-hour military field exercise.

Methods: Forty-four British Army Officer cadets (14 women) completed a 36-hour field exercise. Participants consumed their habitual diet (n = 14 women [Women] and n = 15 men [Men Controls]) or the habitual diet and an additional 46.6 g·d–1 protein in supplemental bar form (n = 15 men [Men Protein]). Women and Men Protein were independently compared with Men Controls to examine the effect of sex and protein supplementation. Circulating markers of bone and calcium metabolism were measured before, 24 hours after (post-exercise), and 96 hours after (recovery) the field exercise. Women and Men Controls, and Men Controls and Men Protein were compared over time with linear mixed effects models.

Results: βCTX, 1,25(OH)2D, and cortisol were not different between timepoints or Women and Men Controls (p ≥ 0.094). PINP decreased from baseline to post-exercise (mean difference [95% CI], −13.5 [10.3, 16.8] μg∙L-1, p < 0.001) and recovery (−7.6 [3.3, 11.8] μg∙L-1, p < 0.001) in Women and Men Controls. PTH increased from baseline to postexercise (0.7 [0.3, 1.1] pmol∙L-1, p = 0.006) and decreased from post-exercise to recovery (−0.5 [−1.0, −0.1] pmol∙L-1, p = 0.047) in Women and Men Controls. Total 25(OH)D increased from baseline to post-exercise (4.5 [0.8, 8.3] nmol∙L-1, p = 0.038) and recovery (9.5 [5.7, 13.3] nmol∙L-1, p < 0.001) in Women and Men Controls. Testosterone decreased from baseline to post-exercise (−7.0 [−8.9, −5.2] nmol∙L-1, p <0.001) and recovery (−2.2 [−4.7, 0.3] nmol∙L-1, p = 0.007) in Men Controls, but did not change for Women (all p = 1.000). Protein supplementation had no effect on any biochemical marker.

Conclusions: Men and women experience similar changes to bone metabolism—decreased bone formation and increased PTH—following a short arduous field exercise. Supplementary protein had no protective effect likely because of the severity of energy deficit.

Military Impact: Recovery should be managed following arduous field exercise in energy deficit to allow the recovery of bone formation.

SUBMIT ABSTRACT