The counter-movement jump (CMJ) test is a standard measure of lower body power and can be related to other aspects of athletic performance. With many tools commercially available, it can be difficult for professionals to distinguish which device provides the most accurate results for the best cost. While these devices have been previously validated individually, no past studies have concurrently examined these specific tools. The purpose of this study was to determine the accuracy of four different CMJ measuring devices when compared to the gold standard of a force plate. Thirty-one physically active university students were recruited for this study. Upon completion of a short dynamic warm-up and instruction on proper jumping technique, each participant performed four maximal CMJs on the force plate. They then performed an additional four maximal CMJs in an area where four other instruments were used to measure CMJ simultaneously: accelerometer-based sensor, a contact mat, a photoelectrical cell system, and a mobile device video app. Analysis of the data was conducted, and results showed that while slightly overestimating measurements, the commercial devices that seem to agree the closest to the gold standard force plate were the contact mat and accelerometer-based sensor
