Reliability of a standing isokinetic shoulder rotators strength test using a functional electromechanical dynamometer: effects of velocity

Abstract

Background The evaluation of the force in internal rotation (IR) and external rotation (ER) of the shoulder is commonly used to diagnose possible pathologies or disorders in the glenohumeral joint and to assess patient’s status and progression over time. Currently, there is new technology of multiple joint isokinetic dynamometry that allows to evaluate the strength in the human being. The main purpose of this study was to determine the absolute and relative reliability of concentric and eccentric internal and external shoulder rotators with a functional electromechanical dynamometer (FEMD). Methods Thirty-two male individuals (21.46 ± 2.1 years) were examined of concentric and eccentric strength of shoulder internal and external rotation with a FEMD at velocities of 0.3 m s−1 and 0.6 m s−1. Relative reliability was determined by intraclass correlation coefficients (ICC). Absolute reliability was quantified by standard error of measurement (SEM) and coefficient of variation (CV). Systematic differences across velocities testing circumstances, were analyzed with dependent t tests or repeated-measures analysis of variance in case of 2 or more than 2 conditions, respectively. Results Reliability was high to excellent for IR and ER on concentric and eccentric strength measurements, regardless of velocity used (ICC: 0.81–0.98, CV: 5.12–8.27% SEM: 4.06–15.04N). Concentric outcomes were more reliable than eccentric due to the possible familiarization of the population with the different stimuli. Conclusion All procedures examined showed high to excellent reliability for clinical use. However, a velocity of 0.60 m s−1 should be recommended for asymptomatic male patients because it demands less time for evaluation and patients find it more comfortable.

Test–Retest Reliability of Functional Electromechanical Dynamometer on Five Sit-to-Stand Measures in Healthy Young Adults

“…Recently, Rodriguez-Perea et al (2021) determined the validity and reliability of the FEMD (Dynasystem, Model Research, Granada, Spain) for assessing the velocity of movement, and the results indicated that the mean velocity values collected with FEMD and LVT were practically perfect correlations (r > 0.99) with low random errors (<0.06 m·s −1 ) [ 41 ]. In addition, the FEMD is reliable for assessing isometric and concentric strength of trunk flexors (CV range = 6.82–7.72) [ 29 ] and the effect of velocity on internal and external shoulder rotators (ICC: 0.81–0.98, CV: 5.12–8.27% SEM: 4.06–15.04 N) [ 39 ]. The previously referenced results are interesting since they allow us to compare the degree of reliability of the FEMD in different exercises, joint ranges, and muscle contraction types, showing that the FEMD is not only reliable for STS (CV < 10%), but also for other functional assessments.…”

“…All measurements were conducted at the faculty research laboratory, using a FEMD (Dynasystem, Model Research, Granada, Spain). The FEMD corresponds to a new technology that allows the evaluation and training of strength in humans, generating linear isokinetic velocities, dynamic modes (tonic, kinetic, elastic, inertial, conical) and static (isometric, vibratory), and allows for the evaluation and training through resistance/constant velocity and/or variables [ 39 , 40 , 41 ]. For each experimental session, the participants were invited to the laboratory after a four-hour fast, having rested and without having consumed caffeine 24 h before the experimental session.…”

Isokinetic Trunk Strength in Acute Low Back Pain Patients Compared to Healthy Subjects: A Systematic Review

“…For the reasons mentioned earlier, we consider it necessary to carry out new studies of high methodological quality that allow us to clarify if there are levels of strength associated with ALBP and to be able to prevent its appearance. In addition, given the questions regarding the evaluation of unnatural movements or those that do not necessarily represent the physiology or velocity of the movement performed on the isokinetic dynamometer [ 57 ], it is necessary to develop new technologies [ 28 , 58 ] that allow the evaluation of trunk strength related to a functional or athletic context that mimics the functional demands of the athlete or patient.…”

Test-retest reliability of a functional electromechanical dynamometer on swing eccentric hamstring exercise measures in soccer players

“…This exercise, we propose, simulates the late swing phase of high speed running by combining hip flexion with knee extension, a mechanism performed during the sprint (Chumanov, Heiderscheit & Thelen, 2011;Chumanov et al, 2012). Similarly, it is also important to use measuring devices that allow movements similar to sports specific movement to be replicated, such as a functional electromechanical dynamometer (FEMD), which allows us to assemble the eccentric phase from the concentric phase and execute the movement at different contraction velocities (Jerez-Mayorga et al, 2019Rodriguez-Perea et al, 2019Soriano-Maldonado et al, 2019;Fàbrica et al, 2020;Martinez-Garcia et al, 2020;Machado-Payer et al, 2020) . According to Dvir & Muller (2019) multiarticular isokinetic dynamometers (MID) such as FEMD can be applied validly and effectively to evaluate specific movement patterns, since there is no situation or action where only one muscle is working in isolation.…”