The influence of U.S. Army Basic Initial Entry Training on the maximum voluntary isometric strength (MVIS) and anthropometric parameters of men and women was investigated. Significant increases in weight and lean body mass (LBM) and decreases in percent body fat were found for both sexes during training. Significant increases in the MVIS of the upper torso (UT), leg extensors (LE), and trunk extensors (TE) were also found for both sexes. Females and males improved about the same amount on the LE (12.4% and 9.7%, respectively) but females improved significantly more than males on the UT (9.3% and 4.2%, respectively) and TE (15.9% and 8.1%, respectively). The greater gains in the females were presumably due to their lower initial strength levels and the consequently greater relative training stimulus. When strength was expressed relative to LBM, both sexes were able to exert similar amounts of strength on the LE and TE, suggesting that differences in strength between the sexes may primarily be a function of muscle mass.