A new reliable device to assess trunk extensors strength

Abstract

Purpose: This study aimed to examine the reliability of trunk extensor strength assessment with a functional electromechanical dynamometer (FEMD). Methods: Thirty-one men performed strength assessment at different velocities (V) (V1 = 0.15 m·s−1, V2 = 0.30 m·s−1, V3 = 0.45 m·s−1) and range of movement (R) (R1 = 25% cm; R2 = 50% cm), and isometric contraction at 90º. Reliability was obtained through the intraclass correlation coefficient (ICC), typical error (TE), and coefficient of variation (CV). Results: The absolute reliability provided stable repeatability of the average eccentric strength in the V1R1 condition (CV = 9.52%) and the maximum eccentric strength in V1R1 (CV = 9.63%) and V2R2 (CV = 9.66%). The relative reliability of the trunk extensor’s average strength was good (ICC = 0.77–0.83) for concentric and good (ICC = 0.78–0.85) and moderate (ICC = 0.67–0.74) for eccentric contraction. Also, good (ICC = 0.77–0.81) and moderate (ICC = 0.55–0.74) reliability of the maximum strength were obtained for concentric and eccentric contraction. The most reliable manifestation to evaluate the concentric (CV = 11.33%) and eccentric (CV = 9.52%) strength was the average strength in the V1R1 condition and the maximum strength (CV = 10.29%) to isometric assessment. The average concentric strength in the V2R2 condition (r = 0.69) and the maximum eccentric strength in the V1R1 condition (r = 0.65) were the best related to the maximum isometric strength. Conclusions: FEMD is a highly reliable device to evaluate trunk extensors strength.

Test–Retest Reliability of the Functional Electromechanical Dynamometer for Squat Exercise

“…The results demonstrated that the PF variables calculated from the performance of the isometric mid-thigh pull on FEMD were reliable (CV < 3%; ICC > 0.90). In parallel, Reyes-Ferrada et al [24] examined the reliability of trunk extensor strength assessment with FEMD at different velocities (0.15 m•s −1 , 0.30 m•s −1 , and 0.45 m•s −1 ), range of movements (25% cm and 50% cm), and isometric contraction at 90 • and concluded that FEMD is a highly reliable device to evaluate trunk extensors strength. The study by Rodriguez-Perea et al [23] determined the reliability and concurrent validity of a FEMD to measure different isokinetic velocities (0.40, 0.60, 0.80, 1.00, and 1.20 m•s −1 ).…”

“…(2) the familiarization process performed before the start of official data collection [20,[22][23][24]. On the other hand, although there are no universally accepted thresholds for classifying CV, values below 5% are generally considered acceptable [37].…”

“…Moreover, it has been shown to be a valid and reliable evaluation method [22,23]. This technology has been used to study the strength of different exercises and has obtained high-reliability values [20,[23][24][25][26]. However, the reliability of the squat has not been evaluated with this device.…”

“…In fact, the reliability of this device for performing various exercises has been studied several times in recent years. It has been demonstrated that DEMF is reliable when evaluating a variety of exercises, but most of them focus on the upper body [23,24,26]. To the best of our knowledge, the exercises evaluated by DEMF involving the lower body that has been demonstrated to be reliable have lower biomechanical outputs [20,22].…”

Muscle Quality and Functional and Conventional Ratios of Trunk Strength in Young Healthy Subjects: A Pilot Study

“…Participants completed three isokinetic velocities (0.15 m•s −1 (V 1 ), 0.30 m•s −1 (V 2 ), and 0.45 m•s −1 (V 3 )), isometric conditions, and two range of movement (R) protocols. R was established by measuring the distance between the acromion and greater trochanter [25,26]. The order of the V and R was randomly established.…”