Reliability and Validity of Two Measurement Systems in the Quantification of Jump Performance

Abstract

There are different devices on the market for assessing strength and power in vertical jumping as a fundamental requisite of an athlete’s performance. The purpose of this study was to assess the reliability and validity of two instruments measuring force, power, velocity, and jump height in squat jumps. Myotest® (MYO) (Myotest SA, Switzerland) was compared with force plate measurements (Quattro Jump® [QUATTRO], Kistler, Switzerland & SPSport Software, Trins, Austria). Forty-three frontier-guards (age range 25–58 years) performed twice a series of five squat jumps (SJ) simultaneously using MYO device along with QUATTRO force plate. Reliability was analysed using ICC, CV and RMSE. Results for reliability for both devices show good results with ICCs ranging from 0.910 to 0.955, and CVs ranging from 2.33% to 6.59% for discrete outcome variables. The validity of the methods was investigated using the Limits of Agreement (LoA) method. MYO overestimated jump performance compared to QUATTRO with a bias of 4.38 cm (±2.59) for jump height, 1.82 Watt/kg (±4.08) for power, and 0.85 N/kg (±1.24) for force. For velocity the two methods displayed good agreement. In conclusion, based on the variability of the measurements, coaches may use complemental variables in addition to jump data in the realm of performance testing and training control to better understand the performance of their athletes. In addition, on the basis of the results regarding the validity interchangeability of the two systems is limited.