Use, Validity and Reliability of Inertial Movement Units in Volleyball: Systematic Review of the Scientific Literature.

The use of inertial devices in sport has become increasingly common. The aim of this study was to examine the validity and reliability of multiple devices for measuring jump height in volleyball. The search was carried out in four databases (PubMed, Scopus, Web of Sciences and SPORTDiscus) using keywords and Boolean operators. Twenty-one studies were selected that met the established selection criteria. The studies focused on determining the validity and reliability of IMUs (52.38%), on controlling and quantifying external load (28.57%) and on describing differences between playing positions (19.05%). Indoor volleyball was the modality in which IMUs have been used the most. The most evaluated population was elite, adult and senior athletes. The IMUs were used both in training and in competition, evaluating mainly the amount of jump, the height of the jumps and some biomechanical aspects. Criteria and good validity values for jump counting are established. The reliability of the devices and the evidence is contradictory. IMUs are devices used in volleyball to count and measure vertical displacements and/or compare these measurements with the playing position, training or to determine the external load of the athletes. It has good validity measures, although inter-measurement reliability needs to be improved. Further studies are suggested to position IMUs as measuring instruments to analyze jumping and sport performance of players and teams.

Concurrent Validity and Reliability of Devices to Measure Jump Height in Men's Handball Players.

Although there is a wide range of validated devices to measure vertical jump height, the degree of interchangeability among them is currently unknown. AIMS: The purpose of this study was to examine the concurrent validity and reliability of multiple devices to measure jump height in men's handball players. METHODS: Sixteen players (age = 24.0 ± 3.7 years old) performed three types of jumps (n= 144-squat jump (SJ), countermovement jump (CMJ) and Abalakov jump (ABK)) on a contact platform (CHRONOJUMP®) while simultaneously being measured with two inertial devices (WIMU® and VERT®) and recorded with a high-speed camera. Vertical jump height was analyzed according to each type of jump. RESULTS: The t-test showed statistically significant differences (p = 0.001) between the contact platform (reference standard) and the rest of the tools that tended to overestimate jump height in all jumps. SJ and CMJ proved to be the jump tests with the most stable reliability values in all devices (ICC: 0.92-0.98), except in the comparison with VERT®. CONCLUSIONS: Although all the analyzed devices proved to be valid and reliable in previous studies, they are not interchangeable. Therefore, it is suggested to always use the same type of device to evaluate vertical height jump.