Comparing three devices for jump height measurement in a heterogeneous group of subjects.

The purpose of this study was to compare the accuracy of 3 devices for measuring jump heights of subjects with a range of abilities. The methods used were an accelerometer-based technique (KineJump), a contact mat (Newtest Powertimer 300 series), and the Vertec measurement device. The reference method used was a video analysis technique. Data were collected simultaneously with all 4 methods. Of particular interest was to evaluate the accuracy of the accelerometer device (KineJump) because it has not been systematically compared with other methods in the previous literature. Participants (N = 101) varied from well-trained athletes to sedentary individuals and their ages ranging from 18 to 70 years old. From the statistical analysis, it can be concluded that KineJump has accuracy that is at least as good as the accuracy of the Vertec and contact mat, although the overall accuracy of all the methods was disappointing at typically ± 5 cm. The 2 methods that rely on a time-of-flight calculation of the jump height (contact mat and accelerometer) showed systematically lower values than the other 2 methods. None of the physical parameters showed significant correlation with the measurement error made by the methods, with the exception of a slight positive correlation of height, leg length, and foot length to the error of the Vertec method. Linear regression on the Bland-Altman plots did not reveal a significant correlation between the jump height and the error of a method, except for the Vertec. The 3 jump height measurement devices can be used to evaluate performance in a diverse group of people, but considerable deviation from actual jump height is apparent, depending on the method of calculation.