Estimation of energy balance and training volume during Army Initial Entry Training

Jeremy Mcadam,Kaitlin Mcginnis,Kaelin Young,Michael Roberts,Rian Ory,Joellen Sefton,Andrew D Frugé

doi:10.1186/s12970-018-0262-7

Abstract

BackgroundAdequate dietary intake is important for promoting adaptation and prevention of musculoskeletal injury in response to large volumes of physical training such as Army Initial Entry Training (IET). The purpose of this study was to evaluate training volume and dietary intake and estimate energy balance in Army IET soldiers.MethodsDietary intake was assessed by collecting diet logs for three meals on each of three, non-consecutive days during the first week of IET. Training volume was measured across 13 weeks of training using Actigraph wGT3X accelerometers. Training intensity was classified using Sasaki vector magnitude three cut points. Energy expenditure estimates were calculated during weeks two and three of training using the modified Harris-Benedict equation and by estimation of active energy expenditure using metabolic equivalents for each classification of physical activity. All data is presented as mean ± standard deviation.ResultsA total of 111 male soldiers (ht. = ± 173 ± 5.8 cm, age = 19 ± 2 years, mass = 71.6. ± 12.4 kg) completed diet logs and were monitored with Actigraphs. IET soldiers performed on average 273 ± 62 min low, 107 ± 42 min moderate, 26 ± 22 min vigorous, and 10 ± 21 min of very vigorous intensity physical activity daily across 13 weeks. The estimated total daily energy expenditure was on average 3238 ± 457 kcals/d during weeks two and three of IET. Compared to week one caloric intake, there was a caloric deficit of 595 ± 896 kcals/d on average during weeks two and three of IET. Regression analysis showed that body weight was a significant predictor for negative energy balance (adj. R2 = 0.54, p < 0.001), whereby a 1 kg increase in body mass was associated with a 53 kcal energy deficit.ConclusionsBased on week one dietary assessment, IET soldiers did not consume adequate calories and nutrients to meet training needs during red phase (weeks one through three). This may directly affect soldier performance and injury frequency. IET soldiers undergo rigorous training, and these data may help direct future guidelines for adequate nourishment to optimize soldier health and performance.

Highlights

Adequate dietary intake is important for promoting adaptation and prevention of musculoskeletal injury in response to large volumes of physical training such as Army Initial Entry Training (IET)
The primary aims of this study were to: 1) quantify total training volume; 2) determine dietary intake; and 3) estimate energy balance in soldiers participating in IET
Our primary finding was that IET soldiers expended approximately 595 more calories per day during red phase than they consumed based on our estimation of metabolic training load

Summary

Introduction

Adequate dietary intake is important for promoting adaptation and prevention of musculoskeletal injury in response to large volumes of physical training such as Army Initial Entry Training (IET). Initial Entry Training (IET) is a mentally and physically demanding military training program designed to transform civilians into soldiers. Soldiers perform organized physical fitness training as well as occupational physical activity to improve physical fitness and learn soldiering skills during IET [8–10]. Occupational physical activity consists of tactical and survival drills that will enable IET soldiers to carry out required duties for the completion of successful missions. These physical and cognitive efforts must be adequately fueled in order to optimize IET soldier performance

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