Effect of intense military training on body composition.

Individuals in a structural physical training program can show beneficial changes in body composition, such as body fat reduction and muscle mass increase. This study measured body composition changes by using 3 different techniques-skinfold thickness (SF) measurements, air displacement plethysmography (BOD-POD), and dual-energy x-ray absorptiometry (DXA)-during 9 months of intense training in healthy young men engaged in military training. Twenty-seven young men were recruited from a special faction of the Italian Navy. The program previewed three phases: ground combat, sea combat, and amphibious combat. Body composition was estimated at the beginning, in the middle, and at the end of the training. After the subjects performed the ground combat phase, body composition variables significantly decreased: body weight (P < 0.05), fat-free mass (FFM) (P < 0.001), and fat mass (FM) (P < 0.03). During the amphibious combat phase, body weight increased significantly (P < 0.01), mainly because of an increase in FFM (P < 0.001) and a smaller mean decrease in FM. There was a significant difference (P < 0.05) in circumferences and SF at various sites after starting the training course. Bland-Altman analysis did not show any systematic difference between FM and FFM measured with the 3 different techniques on any occasion. On any visit, FFM and FM correlation measured by BOD-POD (P = 0.90) and DXA was significantly greater than measured by SF. A significant difference was found in body mass index (BMI) measured during the study. BOD-POD and SF, compared with DXA, provide valid and reliable measurement of changes in body composition in healthy young men engaged in military training. In conclusion, the findings suggest that for young men of normal weight, changes in body weight alone and in BMI are not a good measure to assess the effectiveness of intense physical training programs, because lean mass gain can masquerade fat weight loss.

A new device for measuring resting energy expenditure (REE) in healthy subjects.

BACKGROUND AND AIM: Lifestyle change targeted towards increasing daily resting energy expenditure (REE) is one of the cornerstones of obesity treatment. Measurements of energy expenditure and substrate utilization are essential to understanding the metabolic basis of obesity, and the physiological responses to perturbations in habitual food intake. REE is the largest part of human energy expenditure (60-70%) and an increase or decrease in REE would have a large impact on total energy. Accurate and easy-to-use methods for measuring REE are needed, to be applied by clinicians in daily clinical settings to assess the validity of a new instrument to estimate REE in normal weight, healthy adults. METHODS: Ninety-nine subjects (52 females and 47 males) (mean+/-SD, age 38+/-14 years; body mass index (BMI) 23+/-3 kg/m(2)) were tested. REE was assessed using a Sensor Medics Vmax metabolic cart with a ventilated canopy and with the SenseWear armband. Body composition, percentage fat mass (%FM) and percentage fat free mass (%FFM) were assessed by skinfold thickness measurements (SF), bio-electrical impedance analysis (BIA) and air displacement plethysmography (BOD-POD). RESULTS: No significant difference was found among measurements of FFM using the three different techniques. Both SenseWear and Sensor Medics Vmax showed a high correlation, r=0.42 and r=0.40 (p<0.0001) respectively, with BMI. No significant difference was found in mean REE between SenseWear (1540+/-280 kcal/day) and Sensor Medics Vmax (1700+/-330 kcal/day) (p=ns) and the correlation between REE measured by SenseWear and Sensor Medics Vmax was high (r=0.86, p<0.0001). Bland-Altman plot showed no difference in REE determination between SenseWear and Sensor Medics Vmax. %FFM determined by BOD-POD correlated with SenseWear (r=0.42, p<0.0001) as well as Sensor Medics Vmax (r=0.38, p<0.001). CONCLUSION: SF, BIA and BOD-POD provide valid and reliable measurements of FFM. Our results suggest that the SenseWear armband is an acceptable device to accurately measure REE in healthy subjects. Its characteristics have the potential to reduce measurement times and make the SenseWear armband useful for epidemiological studies.

Healthy status and energy balance in pediatrics.

During growth, the human body increases in size and changes proportion of various components due to hormones mediators. Nutritional status is the result of introduction, absorption and utilization of the nutrients and it has a new definition in the relationship between nutritional status and healthy status. In this view energy balance, body function and body composition are three entities correlated each other. This mini-review article examines issues and techniques specifically related to a pediatric population in the field of body composition and energy expenditure. It is broadly divided into two sections. The first section discusses body composition measurements underlying principles, advantages, disadvantages and consensus. The second section reviews energy expenditure and physical activity measurement techniques. In conclusion general clinical suggestions are offered regarding pediatric body composition, healthy status and energy balance.