Reliability of isometric and isokinetic trunk flexor strength using a functional electromechanical dynamometer

Abstract

AimTo determine the absolute and relative reliability of functional trunk tests, using a functional electromechanical dynamometer to evaluate the isokinetic strength of trunk flexors and to determine the most reliable assessment condition, in order to compare the absolute and relative reliability of mean force and peak force of trunk flexors and to determine which isokinetic condition of evaluation is best related to the maximum isometric.MethodsTest-retest of thirty-seven physically active male student volunteers who performed the different protocols, isometric contraction and the combination of three velocities (V1 = 015 m s−1 , V2 = 0.30 m s−1, V3 = 0.45 m s−1) and two range of movement (R1 = 25% cm ; R2 = 50% cm) protocols.ResultsAll protocols to evaluate trunk flexors showed an absolute reliability provided a stable repeatability for isometric and dynamic protocols with a coefficient of variation (CV) being below 10% and a high or very high relative reliability (0.69 < intraclass correlation coefficient [ICC] > 0.86). The more reliable strength manifestation (CV = 6.82%) to evaluate the concentric contraction of trunk flexors was mean force, with 0.15 m s−1 and short range of movement (V1R1) condition. The most reliable strength manifestation to evaluate the eccentric contraction of trunk flexors was peak force, with 0.15 m s−1 and a large range of movement (V1R2; CV = 5.07%), and the most reliable way to evaluate isometric trunk flexors was by peak force (CV = 7.72%). The mean force of eccentric trunk flexor strength with 0.45 m s−1 and short range of movement (V3R1) condition (r = 0.73) was best related to the maximum isometric contraction.ConclusionFunctional electromechanical dynamometry is a reliable evaluation system for assessment of trunk flexor strength.

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.…”

“…Arms and legs can be compared with their contralateral to define deficits or imbalances but, unlike the extremities, the trunk does not have this possibility, which makes it difficult to find parameters of normality or reference. Trunk strength has been related to injury prevention [ 25 , 26 ], which is why it plays an important role in the functional evaluation of people or athletes [ 27 , 28 ].…”

Physical Abilities in Low Back Pain Patients: A Cross-Sectional Study with Exploratory Comparison of Patient Subgroups

“…This dynamometer is considered as a gold standard device and has been used in previous studies [ 37 , 38 ]. Similar procedures have also been proven reliable with less complex trunk dynamometers [ 39 ]. For the assessment of the lateral flexors of the trunk, the participant was positioned in the middle of the dynamometer with the shoulders positioned against the lateral force meter and arms crossed in front of the abdomen.…”

Effects of slackline training on core endurance and dynamic balance (Efectos del entrenamiento en slackline sobre la resistencia del core y el equilibrio dinámico)

“…It is considered that the core is the center of the kinetic chains, transferring forces and acting as a bridge between the upper and lower extremities, which provides proximal stability for distal mobility (Kibler et al, 2006). The function of the core muscles is usually assessed in terms of strength (Estrázulas et al, 2020;Rodriguez-Perea et al, 2019), stability (Barbado et al, 2016;Bastida Castillo et al, 2017) and/or endurance (Juan-Recio et al, 2018). Trunk endurance is a crucial component in core training (Faries & Greenwood, 2007), since it helps maintain an efficient trunk position, and is of great importance in both, health and sports performance.…”