Does insertion of intramuscular electromyographic electrodes alter motor behavior during locomotion?

Abstract

Intramuscular electromyography (EMG) is commonly used to quantify activity in the trunk musculature. However, it is unclear if the discomfort or fear of pain associated with insertion of intramuscular EMG electrodes results in altered motor behavior. This study examined whether intramuscular EMG affects locomotor speed and trunk motion, and examined the anticipated and actual pain associated with electrode insertion in healthy individuals and individuals with a history of low back pain (LBP). Before and after insertion of intramuscular electrodes into the lumbar and thoracic paraspinals, participants performed multiple repetitions of a walking turn at self-selected and controlled average speed. Low levels of anticipated and actual pain were reported in both groups. Self-selected locomotor speed was significantly increased following insertion of the electrodes. At the controlled speed, the amplitude of sagittal plane lumbo-pelvic motion decreased significantly post-insertion, but the extent of this change was the same in both groups. Lumbo-pelvic motion in the frontal and axial planes and thoraco-lumbar motion in all planes were not affected by the insertions. This study demonstrates that intramuscular EMG is an appropriate methodology to selectively quantify the activation patterns of the individual muscles in the paraspinal group, both in healthy individuals and individuals with a history of LBP.

Insertion and Presence of Fine‐Wire Intramuscular Electrodes to the Lumbar Paraspinal Muscles Do Not Affect Muscle Performance and Activation During High‐Exertion Spinal Extension Activities

“…In fact, participants in our study reported low pain levels despite the insertion and presence of intramuscular electrodes during muscle performance tests. Our results agree with the findings by Armour Smith and Kulig who also reported minimal pain perception during walking (<1/10) after intramuscular EMG electrode insertion [16]. The low pain levels experienced by our participants likely contributed to the similar muscle performance obtained during all 3 conditions of our experiment.…”

“…Previous research has found that anticipated pain, more than actual pain, correlated with altered movement [29]. Related to the current study, Armour Smith and Kulig assessed the anticipated and actual pain levels associated with fine‐wire EMG insertion during walking tasks [16]. They found no significant difference in trunk mechanics during walking, and that low pain levels were reported throughout for both anticipated and actual pain levels [16].…”

“…Related to the current study, Armour Smith and Kulig assessed the anticipated and actual pain levels associated with fine‐wire EMG insertion during walking tasks [16]. They found no significant difference in trunk mechanics during walking, and that low pain levels were reported throughout for both anticipated and actual pain levels [16]. Armour Smith and Kulig hypothesized that because all participants were made aware of the testing procedure, including the intramuscular EMG procedures, those who were fearful and would have likely had higher anticipated pain opted to not participate [16].…”

“…Specific to the intramuscular EMG procedure, Armour Smith and Kulig concluded its use appropriate for quantifying paraspinal muscle activation without significantly altering the trunk movement pattern. However, they examined the intramuscular EMG usage during walking and turning that requires only low‐level muscle contractions (less than 20% of maximum activation) [16]. It is currently unknown how intramuscular EMG affects muscle performance parameters during activities that involve high‐force muscle contractions.…”

Towards an understanding of motor system impairments in individuals with unilateral lateral epicondylalgia

“…Additionally, fine wire electrodes have been proposed as impractical and difficult to use in some contexts because of their invasiveness and potential for discomfort (Rudroff, 2008). Although discomfort is possible and varies depending on the type and intensity of the contraction, recent work has shown that the use of fine wire intramuscular electrodes are associated with minimum discomfort during motor control tasks, <1 out of 10 on the visual analogue scale (Armour Smith & Kulig, 2015).…”