Inter-machine reliability of the Biodex and Cybex isokinetic dynamometers for knee flexor/extensor isometric, concentric and eccentric tests

• Published in: Physical therapy in sport 2015-02, Vol.16 (1), p.59-65
• Main Authors: de Araujo Ribeiro Alvares, João Breno, Rodrigues, Rodrigo, de Azevedo Franke, Rodrigo, da Silva, Bruna Gonçalves Cordeiro, Pinto, Ronei Silveira, Vaz, Marco Aurélio, Baroni, Bruno Manfredini
• Format: Article
• Language: English
• Subjects: Adult; Confidence intervals; Equipment Design; Exercise Test; Hamstring; Human mechanics; Humans; Isokinetic dynamometry; Knee Joint; Laboratories; Male; Muscle Contraction - physiology; Muscle Strength Dynamometer - standards; Muscle, Skeletal - physiology; Physical Medicine and Rehabilitation; Physical therapy; Quadriceps; Quadriceps Muscle - physiology; Rehabilitation; Reproducibility of Results; Sports & recreation clubs; Sports Medicine; Studies; Test–retest; Values; Young Adult
• ISSN: 1466-853X; 1873-1600
• DOI: 10.1016/j.ptsp.2014.04.004

Abstract Objectives To assess the inter-machine reliability of the Biodex System 3 Pro and Cybex Humac Norm Model 770 dynamometers for knee extensor and knee flexor peak torque measurements in isometric, concentric and eccentric tests. Design Randomized/crossover. Setting Exercise Research Laboratory, Federal University of Rio Grande do Sul (Brazil). Participants 25 healthy male subjects. Main outcome measures Isometric, concentric and eccentric knee extensor and knee flexor peak torques recorded in the same test procedure performed on both isokinetic dynamometers. One-way ANOVA, intraclass correlation coefficient (ICC), standard error of measurement (SEM) and coefficient of variation (CV) were used to verify significant differences, relative and absolute reliability between devices. Results No significant differences were found between tests performed on Biodex and Cybex ( p  > 0.05). ICC values indicated a high to very high reproducibility for isometric, concentric and eccentric peak torques (0.88–0.92), and moderate to high reliability for agonist-antagonist strength ratios (0.62–0.73). Peak torque did not show great difference between dynamometers for SEM (3.72–11.27 Nm) and CV (5.27–7.77%). Strength ratios presented CV values of 8.57–10.72%. Conclusion Maximal knee extensor and knee flexor tests performed in isometric (60° of knee flexion), concentric and eccentric modes at 60°/s in Biodex and Cybex dynamometers present similar values.