Today, we are addressing the question "What effect does plyometric based training and dynamic weight training have on energy cost of running?" Before we can address that question we have to define the terms being used. Energy cost of running is defined as the amount of energy used over a certain distance at sub-maximal paces. Plyometric training is designed to improve the ability to store and release elastic energy typically through the means of jumping or hoping. Dynamic weight training is designed to improve the power of certain movements. This article looked at the concentric segment of a squat (standing up from the bottom of a squat) using a guided squat rack. 35 recreational athletes were split up into three groups. The first group is an endurance only group where they only performed three interval style runs a week. The second group is the dynamic weight training group that performed the same interval sessions of the endurance group plus 1 dynamic weight training session a week. The third group is the plyometric training group that also performed the same endurance intervals plus 1 session of plyometric jumps from various heights. The authors concluded that the plyometric group decreased their energy cost of running by 7%, the dynamic weight training group decreased their energy cost by 4%, and no change was noted in the endurance only group. It was determined, that plyometric based training is more efficient at reducing the energy cost of running versus dynamic weight training, and if you are trying to decide between the two, plyometrics will most likely be better at reducing energy cost of running. It is important to note that all subjects in the study had not previously done either plyometrics or dynamic weight training and if someone is already performing this style of training they should not expect the same gains that the subjects in the study experienced.