RESUMO
The aim of the study was to determine changes in body composition and physical fitness during military service. A prospective cohort study of 140 healthy male conscripts was conducted. We examined subject characteristics, aerobic performance and muscle strength, and assessed body composition using dual-energy X-ray absorptiometry (DEXA) three times. Conscripts' mean baseline weight (79.5 kg) decreased by 2 kg during the first 3 months, but increased by 0.9 kg during the second 3-month period (p<0.001). Fat mass measured by DEXA decreased by 3.2 kg during the first but increased by 0.8 kg during the second 3-month period (p<0.001). Throughout the 6-month study, an increase was seen in distance of 12-min run test (from 2 380 m to 2 530 m; p<0.001), and muscle strength score (from 6.5 to 9.5 p<0.001). Finnish military training seems to have beneficial effects on physical fitness. However, considering the relatively modest changes in body fat and physical fitness seen in conscripts with average BMIs at baseline, design of diverse training programmes for the varying baseline BMI levels are warranted to improve the physical fitness results.