A new reliable device to assess trunk extensors strength

Area of Science:

• Biomechanics
• Kinesiology
• Sports Medicine

Background:

• Trunk extensor strength is crucial for athletic performance and injury prevention.
• Accurate and reliable assessment methods are needed to evaluate this muscle group.
• Functional electromechanical dynamometers (FEMD) offer a potential solution for standardized strength testing.

Purpose of the Study:

• To determine the reliability of trunk extensor strength measurements using a functional electromechanical dynamometer (FEMD).
• To assess the impact of different testing velocities and ranges of motion on measurement reliability.
• To compare the reliability of concentric, eccentric, and isometric contractions.

Main Methods:

• Thirty-one male participants underwent trunk extensor strength assessments.
• Testing was performed at three velocities (V1=0.15, V2=0.30, V3=0.45 m/s) and two ranges of motion (R1=25%, R2=50%), plus isometric contractions at 90°.
• Reliability was quantified using intraclass correlation coefficient (ICC), typical error (TE), and coefficient of variation (CV).

Main Results:

• High absolute reliability (low CV) was observed for average and maximum eccentric strength in the V1R1 condition.
• Relative reliability (good ICC values) was demonstrated for both concentric and eccentric average and maximum strength across tested conditions.
• The most reliable measures for concentric and eccentric strength were average strength in V1R1, and for isometric strength, maximum strength.

Conclusions:

• The functional electromechanical dynamometer (FEMD) is a highly reliable device for assessing trunk extensor strength.
• The findings support the use of FEMD for consistent and dependable evaluation of trunk extensor function in research and clinical settings.
• Specific testing parameters (V1R1) appear optimal for maximizing reliability in certain strength measures.