Adaptive thermogenesis and changes in body composition and physical fitness in army cadets

Effect of Physical Training on Body Composition in Brazilian Military

The military are selected on the basis of physical standards and are regularly involved in strong physical activities, also related to particular sports training. The aims of the study were to analyze the effect of a 7-month military training program on body composition variables and the suitability of specific ‘bioelectrical impedance vector analysis’ (spBIVA), compared to DXA, to detect the changes in body composition. A sample of 270 male Brazilian cadets (19.1 ± 1.1 years), composed of a group practicing military physical training routine only (MT = 155) and a group involved in a specific sport training (SMT = 115), were measured by body composition assessments (evaluated by means of DXA and spBIVA) at the beginning and the end of the military routine year. The effect of training on body composition was similar in SMT and MT groups, with an increase in LST. DXA and spBIVA were correlated, with specific resistance (Rsp) and reactance (Xcsp) positively related to fat mass (FM), FM%, LST, and lean soft tissue index (LSTI), and phase angle positively related to LST and LSTI. Body composition variations due to physical training were recognized by spBIVA: the increase in muscle mass was indicated by the phase angle and Xcsp increase, and the stability of FM% was consistent with the unchanged values of Rsp. Military training produced an increase in muscle mass, but no change in FM%, independently of the sample characteristics at baseline and the practice of additional sports. SpBIVA is a suitable technique for the assessment of body composition in military people.

Adaptive thermogenesis after moderate weight loss: magnitude and methodological issues

PURPOSE

The aim of this study was (1) to assess AT through 13 different mathematical approaches and to compare their results; and (2) to understand if AT occurs after moderate WL.

METHODS

Ninety-four participants [mean (SD); BMI, 31.1 (4.3) kg/m²; age, 43.0 (9.4) years; 34% females] underwent a 1-year lifestyle intervention (clinicaltrials.gov ID: NCT03031951) and were randomized to intervention (IG, n = 49) or control groups (CG, n = 45), and all measurements were made at baseline and after 4 months. Fat mass (FM) and fat-free mass (FFM) were measured by dual-energy X-ray absorptiometry and REE by indirect calorimetry. AT was assessed through 13 different approaches, varying in how REE was predicted and/or how AT was assessed.

RESULTS

IG underwent a mean negative energy balance (EB) of 270 (289) kcal/day, p < 0.001), resulting in a WL of - 4.8 (4.9)% and an FM loss of - 11.3 (10.8)%. Regardless of approach, AT occurred in the IG, ranging from ~ - 65 to ~ - 230 kcal/day and three approaches showed significant AT in the CG.

CONCLUSIONS

Regardless of approach, AT occurred after moderate WL in the IG. AT assessment should be standardized and comparisons among studies with different methodologies to assess AT must be avoided.

Influence of Physical Fitness and Attention Level on Academic Achievements of Female and Male Military Academy Cadets in Poland

A professional soldier should be characterized not only by high physical fitness but also by high intellectual and cognitive skills. Therefore, it is important to focus on the future commanding cadre-cadets that are educated in military academies. The aim of the study was to look for correlations between the level of physical fitness and attention and academic achievements (AA) in different subjects among cadets studying at military academies. The research group consisted of students of a military academy in Poland, i.e., 228 cadets, including 31 women and 197 men. Correlations between explained and explanatory variables were assessed using Pearson’s correlation. Correlations between AA and somatic parameters and motor components were analysed using optimal regression, using the best subset method. A statistical difference was found between men and women in terms of the level of somatic and motor development; men also performed significantly better in practical military subjects. In the female group, dominant hand strength is a significant determinant of AA in civilian and theoretical military subjects. The findings suggest the need for specialized training aimed at bridging the major differences in physical fitness between men and women by placing greater emphasis on muscle strength development.

Body mass index and waist-to-hip ratio misclassification of overweight and obesity in Chinese military personnel

BACKGROUND

The rising prevalence of obesity in military personnel has raised great concerns. Previous studies suggest that body mass index (BMI)- and waist-to-hip ratio (WHR)-based obesity classifications in US military personnel and firefighters have high false negative and subsequently cause obesity misclassification.

OBJECTIVE

To determine whether BMI and WHR could reflect the fat mass of Chinese military personnel.

METHODS

Three hundred fifty-three male Chinese military personnel and 380 age-matched male adults were recruited. Obesity classification was defined by BMI, WHR, and body fat percentage (BFP).

RESULTS

Chinese military personnel had extremely low obesity rate determined by either BFP (0.3%) or BMI (0.6%). By combining overweight and obese individuals, BMI- and WHR-determined prevalence of overweight/obesity was 22.4% and 17.0% compared to BFP-based standard (4.0%) (P < 0.05). In reference to BFP, BMI and WHR have high false-positive rate compared to the control group. Further analysis showed that Chinese military personnel consisted of high percentage of BFP^lowBMI^high and/or BFP^lowWHR^high subpopulations. Eighty-one percent of BMI^high and 78.3% of WHR^high of them were BFP low.

CONCLUSIONS

Chinese military personnel has extremely low obesity rate. BMI and WHR have high false-positive rates in reference to BFP, which cannot accurately reflect the mass of adipose tissue and leads to obesity misclassification.