Seven healthy, untrained men (age 60 +/- 2 yr, mean +/- SEM) were studied to determine the effects of a 13-wk total body strength training program on gastrointestinal transit time (GITT). Whole bowel transit time and mouth-to-cecum transit time were assessed before and after the training program. Subjects recorded dietary intake for the 5 d preceding their baseline GITT tests and repeated that diet for 5 d prior to their GITT tests after training. No significant changes in weight or VO2max were observed as a result of the training program. There was a small but significant decrease in body fat assessed by hydrodensitometry (23.4 +/- 2.6% vs 21.8 +/- 2.6%, P less than 0.05). The training program resulted in a 41 +/- 5% increase (P less than 0.001) in upper body strength and a 45 +/- 6% increase (P less than 0.001) in lower body strength. A 38 +/- 6% increase (P less than 0.01) in peak torque of the knee extensors was also observed at 60 degrees.s-1. The training program significantly accelerated whole bowel transit time (41 +/- 11 vs 20 +/- 7 hr; P less than 0.01). There was no significant change in mouth-to-cecum transit time. Thus, a strength training program can accelerate whole bowel transit time in previously sedentary middle-aged and older men. This effect appears to be in the large intestines.