METROLOGY APPLIED TO THE PRODUCTION OF ISOMETRIC TORQUE OF THE KNEE FLEXOR-EXTENSORS: REPRODUCIBILITY AND RESPONSIVENESS USING A PORTABLE TRACTION DYNAMOMETER

Introduction: Measures of muscle strength and/or torque, limb symmetry (SI) and the ischium/quadriceps ratio (R-I/Q) are widely used in clinical and sports settings. It is crucial to ensure their reproducibility. Objective: To determine reproducibility and responsiveness, using the Dinabang, for aspects of knee flexor-extensor muscle function measured isometrically. Methods: An observational test-retest study with 20 volunteers aged 18 to 59. A Dinabang portable traction dynamometer was used to obtain maximum isometric torque (MIT) measurements. The volunteers were assessed bilaterally for the MITflexors and MITextensors outcomes using the test-retest approach, and the SI and R-I/Q were then calculated. There was a total of one test and two retest measurements, and the assessment procedures were identical for all tests. Relative reproducibility was assessed using the intraclass correlation coefficient (ICC) and absolute reproducibility using the standard error of measurement (SEM). Responsiveness was assessed by the minimum detectable change (MDC). Results: No differences were observed between MIT at different times, neither for MITextensors nor for MITflexors. The SI ICCs of the extensors were moderate and those of the flexors poor; the SEM values indicated high variability (around 85%) and low responsiveness (high MDC values). For R-I/Q, although the ICC was moderate, the SEM was low (with variability of 10.8%) and the responsiveness was acceptable. Conclusions: The MITextensors and R-I/Q measurements showed better reproducibility and responsiveness than those measured by MITflexors and SI, especially for the SI of the flexors