Related Experiment Videos
Neck Muscle EMG-Force Relationship and Its Reliability During Isometric Contractions
Riccardo Lo Martire1,2,3, Kristofer Gladh4,5, Anton Westman4,5,6
1Division of Physiotherapy, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Alfred Nobels allé 23 100, Huddinge, 141 83, Sweden. riccardo.lo.martire@ki.se.
Sports Medicine - Open
|April 16, 2017
Summary
This study models the relationship between surface electromyography (EMG) and neck muscle force, finding it reliable within days for estimating cervical loads. Models are generally acceptable, aiding future biomechanical research.
Area of Science:
- Biomechanics
- Neuroscience
- Kinesiology
Background:
- The neck is prone to injury, necessitating research into injury mechanisms.
- Surface electromyography (EMG) is used to estimate cervical loads indirectly.
- Accurate EMG-based load estimation requires understanding the EMG-force relationship and its measurement error.
Purpose of the Study:
- To examine the relationship between EMG and isometric force amplitude in anterior neck (AN), upper posterior neck (UPN), and lower posterior neck (LPN).
- To assess the test-retest reliability of these EMG-force relationships across different force levels and over time.
Main Methods:
- Collected EMG and force data from 18 participants during isometric neck contractions (5-90% maximal voluntary force) over 2 days.
- Modeled EMG-force relationships using general linear mixed-effects regression.
- Quantified reliability using intraclass correlation coefficient (ICC) and standard error of measurement (SEM).
Main Results:
- Rectilinear and quadratic models best described EMG-force relationships for AN, UPN, and LPN, respectively (R-squared 0.97-0.98).
- Between-trial discrepancies were a maximum of 6%, with reliability (ICC) higher within days (>0.79) than between days (0.27-0.61).
- SEM was generally below 12%, indicating acceptable measurement precision, except for UPN between days.
Conclusions:
- Established EMG-force relationships for three neck regions, enabling group-level inferences from EMG to force.
- Demonstrated higher reliability of EMG-force models within-day compared to between-day measurements.
- Concluded that these models are typically acceptable, especially for higher contraction intensities, and can help adjust for measurement imprecision in future studies.