Lemos, A, Simão, R, Polito, M, Salles, B, Rhea, MR, and Alexander, J. The acute influence of two intensities of aerobic exercise on strength training performance in elderly women. J Strength Cond Res 23(4): 1252-1257, 2009-The aim of this study was to compare the acute influence of 2 intensities of aerobic exercise on a strength training session in physically active elderly women. Twenty-five women (74.3 ± 2.8 years) with previous experience in both resistance and aerobic exercise volunteered to perform aerobic activity (60 and 80% maximum heart rate) followed by a training session on leg press, leg extension, and leg curl exercises. After aerobic intensity training, the number of repetitions in each set was analyzed to determine whether the aerobic exercise affected the amount of volume completed in a resistance workout. The results showed a significant decrease in the number of repetitions per exercise after aerobic training intensities of 80 and 60%. Ratings of perceived exertion demonstrated that fatigue after the 80% workout was greater than after the 60% workout. It was concluded that, at the training intensities tested, 20 minutes of aerobic training may be enough to produce a negative impact on a strength training performance session of physically active elderly women.