Low back EMG normalization: a comparison of methodologically induced variance across common employed sub-maximal and maximal voluntary contraction tasks
In ergonomics research, work task EMG recordings are typically normalized to maximal voluntary exertions (MVE) or sub-maximal reference voluntary exertions (RVE). Traditionally, normalization using MVEs have been preferred given the inherent physiological benchmark, however, maximal efforts are not possible for all study populations and, further, some studies have shown better repeatability and better sensitivity to low level differences when utilizing sub-maximal normalization contractions. Currently, a wide range of normalization postures and efforts are utilized to normalize erector spinae (ES) EMG, however, little research has been done to quantify or compare the repeatability of these different techniques. Further, no known quantification has been made of the variability introduced uniquely to work task EMG data via the process of normalization.
ObjectivesTo quantify the variance introduced to thoracic and lumbar EMG uniquely through normalization; to compare the magnitude of variance introduced for nine sub-maximal and three maximal effort normalization tasksTo examine the relative size of the variance due to normalization as compared with the biological and inter-subject variance.
Anticipated Contributions to the Literature
- Quantification and comparison of the magnitude of variance uniquely attributable to the methodological process of normalizing lumbar and thoracic erector spinae EMG data using 9 commonly employed sub-maximal reference contraction tasks.
- Quantification of repeatability for 9 sub-maximal and 3 maximal normalization tasks
- Recommendation of normalization task best suited to minimize induced error for EMG data collection at three sites along the ES musculature.
PhD StudentJennie Jackson
CollaborationProf. Svend Erik Mathiassen, CBF