Purpose: To compare training load and energy expenditure during an 8-week military BT period among individuals having different fitness level using objective measurements in an authentic environment.

Methods: Thirty-four voluntary male conscripts (age 19.1±0.3 years) were divided into three training groups (inactive, moderate, active) by their reported physical activity (PA) level evaluated by the International Physical Activity Questionnaire (IPAQ) prior to military service. Maximal oxygen uptake (VO2max) and heart rate (HR) were determined by maximal treadmill test in the beginning and after 4 and 7 weeks of BT. During BT, HR monitors and accelerometers were used to measure PA and energy expenditure. HR data were used to calculate the training load (TRIMP, training impulse) for each day, week and the whole BT period.

Results: Training load of BT was comparable to training of competitive athletes at the highest level. The training groups differed (p<0.001-0.05) in terms of VO2max to each other (inactive 36±6, moderate 42±6, active 48±6 ml/kg/min). The conscripts in the inactive group were the most loaded during the study period (TRIMPinactive 12393±2989 vs. TRIMPmoderate 10252±1337, p<0.05 and TRIMPactive 8444±2051, p<0.01). The PA intensity of different military tasks during the BT period were low or moderate (<6MET).

Conclusion: The remarkable training load during BT period is comparable to the training loads of professional athletes participating three weeks’ cycling competition. The training load in basic training period was, however, primary due to duration of low intensity activities including only some high intensity military activities. In the future, measuring the training load during the military service is recommended in order to customize the physical training for conscripts regarding his/her fitness level as much as possible.