Intensity of Physical Activity Performed During U.S. Army Basic Combat Training

Purpose The purpose of this study was to measure and compare physical activity (PA) intensity performed during 10 weeks of U.S. Army Basic Combat Training (BCT) at two training sites (Ft Jackson, SC; Ft Sill, OK).

Methods 264 recruits from 11 companies wore an ActiGraph on their waist during waking hours for a 10 week BCT. The average daily time (min) and percent time (%T) recruits spent in four intensities (Sedentary, Light, Moderate and Vigorous) were recorded. T-tests were used to compare %T between posts. Analysis of variance with Tukey post-hoc tests were used to compare time in each intensity across three training phases.

Results Recruits wore the ActiGraph for 760.9±134.6 min/d for 50.3±2.4 days at Jackson and 696.0±114.8 min/d for 46.0±0.7 days at Sill. Recruits at Jackson spent a larger %T than Sill recruits in Light (22.7±11.7 vs. 15.8±3.5, p<0.05) and Moderate (13.7±4.1 vs. 12.3±4.2, p<0.05) PA. Conversely, Jackson recruits spent a smaller %T than Sill recruits in Sedentary (59.4±12.6 vs 65.8±7.0, p<0.05) and Vigorous (4.3±3.9 vs. 6.1±4.4, p<0.05) PA. Table 1 shows average daily time recruits spent in each intensity by training phase. No differences were observed in average daily time spent in moderate PA between training phases for recruits at Jackson (p>0.05). There were differences in average daily time in all other intensities by phase at both training sites (p<0.05).

Conclusions Differences in intensities between training sites varied between 10% and 40%. Sill had smaller differences among phases (4% – 19%) than Jackson (0% – 80%). Table 1. Average±SD daily time (min) Recruits at Forts Jackson (n=144) and Sill (n=120) Spent in Each Intensity by Phase