Secular Trends in the Physical Fitness of United States Army Infantry Units and Infantry Soldiers, 1976-2015.

Introduction: The purpose of this investigation was to examine changes over time in the physical fitness of the United States (US) Army infantry. A systematic review was conducted to identify and analyze articles and databases that reported on physical characteristics (height, weight, and body mass index) and/or Army Physical Fitness Test (APFT) scores of male infantrymen or men in infantry units.

Materials and Methods: The National Library of Medicine's PubMed and the Defense Technical Information Center were searched using specific keywords. Reference lists of obtained articles, specific author searches, contact with authors, and secondary analysis of available databases enhanced the search. Studies and databases were selected if they involved infantry soldiers or soldiers in infantry units and provided a quantitative assessment of at least one physical characteristic or APFT measure. Average values for each measure were obtained, plotted by the year of data collection, and fitted to linear regression models.

Results: Thirty-one articles and five available databases met the review criteria encompassing years 1976-2015. Regression analysis suggested a small temporal increase in height for infantry soldiers (2%) and soldiers in infantry units (1%). Body weight and body mass index increased over the period (9-15%) in both groups. APFT performance of infantry soldiers was generally higher than that of infantry units. There was little change in APFT performance over the period for infantry soldiers. For soldiers in infantry units, push-up performance changed little over time, whereas sit-up performance increased (8%) and two-mile run performance decreased (8%).

Conclusion: Over the surveyed period, body weight and body mass index increased in US Army infantry soldiers and soldier in infantry units. Infantry soldier performance on the APFT appears to have been maintained over the period. For soldiers in infantry units, there has been a small improvement in sit-up performance, but lower two-mile run performance.