Several factors influence the height measurements recorded by each of the systems. The accuracy of the Vertec depends on the ability of the subject to contact the vanes of the device at the peak of the jump. The subject must have sufficient shoulder range of motion and precise timing and coordination of arm swing to insure that the measurement is recorded at the maximum height of the jump. The measurements can be underestimated if the participant does not make contact with the vanes at the peak height of the jump