Reliability of isometric and isokinetic trunk flexor strength using a functional electromechanical dynamometer
Angela Rodriguez-Perea1, Luis J Chirosa Ríos1, Dario Martinez-Garcia1
1Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Granada, Spain.
Peerj
|November 8, 2019
Summary
This study found that functional electromechanical dynamometry offers reliable assessment of trunk flexor strength. Specific protocols demonstrated high reliability for both isometric and dynamic trunk flexor strength measurements.
Area of Science:
- Biomechanics
- Exercise Physiology
- Sports Science
Background:
- Trunk flexor strength is crucial for athletic performance and injury prevention.
- Reliable assessment methods are needed to evaluate trunk flexor strength accurately.
- Functional electromechanical dynamometry offers a potential solution for objective strength measurement.
Purpose of the Study:
- To determine the absolute and relative reliability of functional trunk tests using an electromechanical dynamometer.
- To identify the most reliable assessment conditions for trunk flexor strength.
- To compare the reliability of mean force and peak force measurements.
Main Methods:
- Test-retest reliability study involving 37 physically active male students.
- Evaluated trunk flexors using isometric contractions and isokinetic protocols at three velocities (0.15, 0.30, 0.45 m/s) and two ranges of motion (25%, 50%).
- Assessed both mean force and peak force for reliability.
Main Results:
- All tested protocols demonstrated good absolute and relative reliability (CV < 10%, ICC > 0.69).
- For concentric contractions, mean force at 0.15 m/s with a short range of motion (V1R1) was most reliable (CV = 6.82%).
- For eccentric contractions, peak force at 0.15 m/s with a large range of motion (V1R2) was most reliable (CV = 5.07%).
- Peak force for isometric contractions was also highly reliable (CV = 7.72%).
- Eccentric mean force (V3R1) showed the strongest correlation with maximum isometric contraction (r = 0.73).
Conclusions:
- Functional electromechanical dynamometry provides a reliable system for assessing trunk flexor strength.
- Specific isokinetic conditions offer superior reliability for different strength measures (mean vs. peak force) and contraction types (concentric vs. eccentric).
- These findings support the use of this technology for objective evaluation in clinical and sports settings.
