This article reviews research relating to the stretch-shortening cycle and plyometrics. The article instructs strength and conditioning practitioners in the use of ground contact times and the reactive strength index in plyometric training. Documentation on how these measurements can be used to optimize plyometrics and to improve athletes' fast stretch shortening cycle performance is provided. Recommendations are made regarding the use of ground contact times to improve training specificity and the use of the reactive strength index to optimize plyometrics, to monitor training progress, and to serve as a motivational tool. A 4-step progression of implementation is detailed. Copyright © National Strength and Conditioning Association.