Introduction: Training is more important than technology (for performance in the cold).

After more than 50 years of studying soldiers in the cold, we are well past the phase of defining the unique problems; the research requirements are known but the solutions have been slow in coming. This requires iterative testing of proposed lab-based solutions with soldiers in the real environment. Representing a renewed effort to produce and implement solutions to human biomedical challenges in Arctic operations, this journal supplement highlights presentations from a three-day NATO Human Factors and Medicine panel-sponsored symposium in Washington DC in October 2022. While technology can certainly aid soldiers in extreme environments, it is ultimately training that is the most important factor for ensuring optimal performance and survival. By investing in the development of specialized Arctic forces training and implementing new solutions to protect their health and performance, we can ensure success in the coldest and harshest of environments.

Validation and Practical Applications of Performance in a 6-Min Rowing Test in the Danish Armed Forces.

Personnel of the Danish Armed Forces must complete a yearly basic physical fitness test consisting of a Cooper's 12-min run test (CRT) and four strength-related bodyweight exercises. However, there is no validated alternative to the CRT allowing injured or sailing personnel to conduct the yearly basic physical fitness test. Therefore, the aim of this study was to validate performance in a 6-min rowing ergometer test (6MRT) against CRT performance. Thirty-one individuals (M/F: 20/11, age: 34 ± 12 years) employed at the Danish Armed Forces completed testing on two independent days; (I) the CRT on an outdoor track and (II) a 6MRT with pulmonary measurements of breath-by-breath oxygen uptake. In addition, 5 participants (M/F: 4/1, age: 40 ± 10 years) completed re-testing of the 6MRT. No difference was observed between VO2max estimated from the CRT and measured during the 6MRT. Absolute VO2max correlated strongly (r = 0.95; p < 0.001) to performance in the 6MRT, and moderately (r = 0.80; p < 0.001) to performance in the CRT. Bodyweight (BW) and fat free mass (FFM) correlated stronger to performance in the 6MRT compared to the CRT. 6MRT re-testing yielded similar performance results. The 6MRT is a valid and reliable alternative to the CRT, allowing injured or sailing personnel of the Danish Armed Forces to complete the basic physical fitness test as required, albeit 6MRT performance demands must be made relative to bodyweight.

The implications of emerging technology on military human performance research priorities.

OBJECTIVES: To demonstrate the need for the military human performance research community to anticipate and evolve with the emergence of new and disruptive battlefield technologies that are changing the fundamental role of the human combatant. METHODS: An international team of military performance researchers drew on relevant literature and their individual national perspectives and experiences to provide an integrated forecast of research priorities and needs based on current trends. RESULTS: Rapid advances and convergence in fields such as robotics, information technology and artificial intelligence will continue to have a revolutionary impact on the battlefield of the future. The disruption associated with these technologies will most acutely be experienced by the human combatant at the tactical level, with increasing cognitive demands associated with the employment and use of new capabilities. New research priorities may include augmented performance of humans-machine teams, enhanced cognitive and immunological resilience based on exercise neurobiology findings, and psychophysiological stress tolerance developed in realistic but safe synthetic training environments. Solving these challenges will require interdisciplinary research teams that have the capacity to work across the physical, digital and biological boundaries whilst collaborating seamlessly with end-users, human combatants. New research methodologies taking full advantage of sensing technologies will be needed to provide rigorous, evidence-based data in real and near-real world environments. Longer term research goals involving biological manipulation will be shaped by moral, legal and ethical considerations and evolving concepts of what it means to be human. CONCLUSION: This paper outlines key recommendations to assist military human performance researchers to adapt their practice in order to match the increasing pace of military modernisation. By anticipating technological change and forecasting possible emerging technologies the military human performance research community can manoeuvre to prioritise research activities today in line with future needs and requirements.

Association between intake of dietary protein and 3-year-change in body growth among normal and overweight 6-year-old boys and girls (CoSCIS).

OBJECTIVE: Growth hormone (GH) affects linear growth and body composition, by increasing the secretion of insulin-like growth factor-I (IGF-I), muscle protein synthesis and lipolysis. The intake of protein (PROT) as well as the specific amino acids arginine (ARG) and lysine (LYS) stimulates GH/IGF-I secretion. The present paper aimed to investigate associations between PROT intake as well as intake of the specific amino acids ARG and LYS, and subsequent 3-year-change in linear growth and body composition among 6-year-old children. DESIGN: Children's data were collected from Copenhagen (Denmark), during 2001-2002, and again 3 years later. Boys and girls were separated into normal weight and overweight, based on BMI quintiles. Fat-free mass index (FFMI) and fat mass index (FMI) were calculated. Associations between change (Delta) in height, FMI and FFMI, respectively, and habitual PROT intake as well as ARG and LYS were analysed by multiple linear regressions, adjusted for baseline height, FMI or FFMI and energy intake, age, physical activity and socio-economic status. SETTING: Eighteen schools in two suburban communities in the Copenhagen (Denmark) area participated in the study. SUBJECTS: In all, 223 children's data were collected for the present study. RESULTS: High ARG intake was associated with linear growth (beta = 1.09 (se 0.54), P = 0.05) among girls. Furthermore, in girls, DeltaFMI had a stronger inverse association with high ARG intake, if it was combined with high LYS intake, instead of low LYS intake (P = 0.03). No associations were found in boys.ConclusionIn prepubertal girls, linear growth may be influenced by habitual ARG intake and body fat gain may be relatively prevented over time by the intake of the amino acids ARG and LYS.

Cardiovascular disease risk factors in 6-7-year-old Danish children: the Copenhagen School Child Intervention Study.

OBJECTIVE: To describe population values in cardiovascular disease (CVD) risk factors such as blood lipids, fasting insulin and glucose and blood pressure in this young age group, and calculate associations to fitness and fatness. METHODS: Participants were 369 boys (6.8 +/- 0.4 years) and 327 girls (6.7 +/- 0.4 years) from preschool classes in Copenhagen. Peak VO2, blood pressure (BP), fat content and anthropometry were determined. A fasting blood sample was analysed for insulin, glucose and blood lipids. Physical activity was measured using accelerometry. RESULTS: Mean BMI, BP and blood lipids were not different between sexes. Fat percentage assessed from skinfolds was higher (21.5% vs. 16.5%) in girls than in boys (P < 0.001). Peak VO2 and physical activity were higher in boys than in girls (8% and 9%, respectively). Peak VO2 associated to fatness independent of body weight (r = 0.41; P < 0.001). Among the CVD risk factors, fitness was associated to high-density lipoprotein (HDL) (r = 0.14; P < 0.01) and physical activity (r = 0.12; P < 0.01). Fatness assessed by skinfold was associated to blood pressure (r = 0.19-0.28; P < 0.001), to fasting glucose (r = 0.11, P < 0.05) and insulin (r = 0.17; P < 0.001). CONCLUSIONS: Mean BP in 6-7-year-old Danish children has decreased since 1979 and BMI has increased modestly since 1986/1987. The lipid profile was similar compared with data from 1973 and 1978 in Danish children. Weak relationships were found between CVD risk factors, fitness and fatness.

The relationship between physical fitness and clustered risk, and tracking of clustered risk from adolescence to young adulthood: eight years follow-up in the Danish Youth and Sport Study.

INTRODUCTION: Cardiovascular disease (CVD) is usually caused by high levels of many risk factors simultaneously over many years. Therefore, it is of great interest to study if subjects stay within rank order over time in both the biological risk factors and the behaviour that influences these risk factors. Many studies have described stability (tracking) in single risk factors, especially in children where hard endpoints are lacking, but few have analysed tracking in clustered risk. METHODS: Two examinations were conducted 8 years apart. The first time, 133 males and 172 females were 16-19 years of age. Eight years later, 98 males and 137 females participated. They were each time ranked into quartiles by sex in four CVD risk factors all related to the metabolic syndrome. Risk factors were the ratio between total cholesterol and HDL, triglyceride, systolic BP and body fat. The upper quartile was defined as being at risk, and if a subject had two or more risk factors, he/she was defined as a case (15-20 % of the subjects). Odds ratios (OR) for being a case was calculated between quartiles of fitness in both cross-sectional studies. The stability of combined risk was calculated as the OR between cases and non-cases at the first examination to be a case at the second examination. RESULTS: ORs for having two or more risk factors between quartiles of fitness were 3.1, 3.8 and 4.9 for quartiles two to four, respectively. At the second examination, OR were 0.7, 3.5 and 4.9, respectively. The probability for "a case" at the first examination to be "a case" at the second was 6.0. CONCLUSIONS: The relationship between an exposure like physical fitness and CVD risk factors is much stronger when clustering of risk factors are analysed compared to the relationship to single risk factors. The stability over time in multiple risk factors analysed together is strong. This relationship should be seen in the light of moderate or weak tracking of single risk factors, and is strong evidence for early intervention in children where risk factors cluster.