Effects of Baseline Fitness and BMI Levels on Changes in Physical Fitness During Military Service

Abstract Objectives The purpose of the present study was to investigate how aerobic fitness, muscle fitness and body mass index (BMI) change in relation to their baseline levels during 6-12 months of military service. Design Retrospective longitudinal follow-up study. Methods The study group consisted of 249 279 healthy young male conscripts (age 19.1 ± 0.4 yrs.) who completed their military service between the years 2005-2015. Anthropometrics (body mass, height, BMI), aerobic fitness (12-minute running test) and muscle fitness (sit-ups, push-ups, standing long jump) were measured. Results A 12-minute running test improved by 5% (107 ± 292 m), standing long jump 1% (2.1 ± 16.2 cm), 1-min sit-ups 19% (4 ± 8 repetitions/min) and 1-min push-ups 33% (5 ± 10 repetitions/min) (p  Conclusions On average, the physical fitness of conscripts improved during their compulsory military service. In particular, conscripts with a lower baseline fitness level or higher BMI showed the largest improvements, which may be significant findings from both a military readiness and national health perspective. However, the decline in physical performance of high-fit conscripts highlights the importance of individualization of physical training and military training load during military service.