Recruits arriving for basic combat training (BCT) between October 1999 and May 2004 were administered an entry-level physical fitness test at the reception station. If they failed the test, then they entered the Fitness Assessment Program (FAP), where they physically trained until they passed the test and subsequently entered BCT. The effectiveness of the FAP was evaluated by examining fitness, injury, and training outcomes. Recruits who failed the test, trained in the FAP, and entered BCT after passing the test were designated the preconditioning (PC) group (64 men and 94 women). Recruits who failed the test but were allowed to enter BCT without going into the FAP were called the no preconditioning (NPC) group (32 men and 73 women). Recruits who passed the test and directly entered BCT were designated the no need of preconditioning (NNPC) group (1,078 men and 731 women). Army Physical Fitness Test (APFT) scores and training outcomes were obtained from a company-level database, and injured recruits were identified from cases documented in medical records. The proportions of NPC, PC, and NNPC recruits who completed the 9-week BCT cycle were 59%, 83%, and 87% for men (p < 0.01) and 52%, 69%, and 78% for women (p < 0.01), respectively. Because of attrition, only 63% of the NPC group took the week 7 APFT, compared with 84% and 86% of the PC and NNPC groups, respectively. The proportions of NPC, PC, and NNPC recruits who passed the final APFT after all retakes were 88%, 92%, and 98% for men (p < 0.01) and 89%, 92%, and 97% for women (p < 0.01), respectively. Compared with NNPC men, injury risk was 1.5 (95% confidence interval, 1.0-2.2) and 1.7 (95% confidence interval, 1.0-3.1) times higher for PC and NPC men, respectively. Compared with NNPC women, injury risk was 1.2 (95% confidence interval, 0.9-1.6) and 1.5 (95% confidence interval, 1.1-2.1) times higher for PC and NPC women, respectively. This program evaluation showed that low-fit recruits who preconditioned before BCT had reduced attrition and tended to have lower injury risk, compared with recruits of similar low fitness who did not precondition.