Aerobic training has been negated as a training modality for many anaerobic sports and their participating athletes. The trend is due to a growing theory that aerobic training has the potential to inhibit strength, power, and/or overall anaerobic performance. However, there are studies that have produced conflicting as well as inconclusive findings when aerobic conditioning is performed concurrently with strength training. PURPOSE: The primary purpose of this research was to investigate the effects of aerobic training on anaerobic output defined by vertical jump (VJ), broad jump (BJ), and Wingate testing results in male and female recreationally trained runners over a period of 16 weeks. Additionally, body weight (BW), percent body fat (PF), pre-exercise resting heart rate (RHR), VO2max and anaerobic threshold (AT) were examined as exploratory measures. METHODS: A 16-week observational pre- and posttest design was used to determine the effects of a single phase aerobic training specific to preparing for a marathon on measures of anaerobic power as well as anthropometric measures and body composition. RESULTS: The primary findings demonstrated that after 16 weeks of a specified aerobic training for a marathon, there was no change in VJ (p = 0.307) and there was an increase in BJ (p = 0.011). There was no change in peak power (males p = 0.08, females p = 0.114). There was an improvement in fatigue index (males p = 0.017, females p = 0.006) during the 30-second Wingate cycle test among study subjects, however there was a decrease in PF (p=0.0001). In addition, marginal increases in VO2max (p = 0.055) as well as decreases in PF (p = 0.001) and RHR (p = 0.001) were observed. CONCLUSION: The findings do not support the notion of the universal nature that aerobic training has a negative effect in the development of rate of force production. However, the adverse effect may hold true in regards to explosive strength due to limited neural activation. The interference effect may also be present in a concurrent setting where aerobic and anaerobic training protocols are assessed in exclusively aerobically trained subjects. However, in a sport performance setting, as well as in general public health, the training for physical fitness requires the development of muscle strength, power and endurance. The present findings indicate that the influence of aerobic training is an important factor for not only overall fitness, but it does not appear to constrain anaerobic performance.