Quantitative intramuscular myoelectric activity of lumbar portions of psoas and the abdominal wall during a wide variety of tasks

Juker, Daniel; McGill, Stuart M.; Kropf, Peter; Steffen, Thomas

doi:10.1097/00005768-199802000-00020

Cited by 213 publications

(158 citation statements)

References 15 publications

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“…Conventionally, curl-up exercises are performed with the upper limbs bent at the elbow joints and hands placed on the chest. Studies have found that activity in the RA muscle varies for this version of the exercise from 50% [9] to 60% [11] of MVC, and is similar in both the lower and upper part of this muscle [12]. A similar result was obtained for this version of the exercise in our study.…”

Section: Discussionsupporting

confidence: 89%

External torque as a factor to modify load in abdominal curl-up exercises

Rutkowska-Kucharska

Szpala

2015

Biomedical Human Kinetics

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SummaryStudy aim: the aim of our study was to evaluate electromyography (EMG) activity in exercises where the load to the muscles is determined by the external torque. In a part of the exercises, we changed the value of the external force, while in the other we modified the length of the lever arm at which the force was applied. Material and methods: the study was carried out on a group of 12 subjects (21 ± 2 years, 61 ± 4.8 mass, 172 ± 5 cm height). Electromyographic activity of the rectus abdominis (RA) muscle was evaluated by recording the EMG signal. The length of the lever arm of the external force was changed by using four different positions of the upper limbs, whereas the magnitude of the external force was changed through adding the weights of 0.5, 1.0, and 1.5 kg. The data recorded were normalized with respect to EMG activity measured under maximum voluntary contraction (MVC) conditions. Results: it was found that the change of the lever arm at which the force was applied (any change in the position of the upper limbs) causes a change in EMG activity in each part of the RA muscle from ca. 50% to ca. 100% MVC (p < 0.001). Further, the change in the external load changes statistically significantly the EMG activity only in the left upper part of the RA muscle (p < 0.05). Conclusions: activity in the RA muscle that increased for longer lever arms of the external force, offers opportunities for changing the load used during the exercise in a manner that is safe for the vertebral column.

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Section: Discussionsupporting

confidence: 89%

External torque as a factor to modify load in abdominal curl-up exercises

Rutkowska-Kucharska

Szpala

2015

Biomedical Human Kinetics

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“…The reason for using different trunk tasks is that they each involve unique combinations of abdominal muscle activity to move the trunk into a new orientation or stabilize the spine. 10,11 As individual abdominal muscles receive innervation from different thoracic segment levels, 12 the assessment of different abdominal muscles should help to further increase the diagnostic accuracy in identifying the specific level and completeness of the SCI. However, to our knowledge, no studies have examined the accuracy of using manual examination to determine abdominal muscle function in persons with SCI.…”

Section: Introductionmentioning

confidence: 99%

Diagnostic accuracy of common clinical tests for assessing abdominal muscle function after motor-complete spinal cord injury above T6

et al. 2014

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Study design: Diagnostic study. Objectives: The objective of this study was to compare patterns of electromyography (EMG) recordings of abdominal muscle function in persons with motor-complete spinal cord injury (SCI) above T6 and in able-bodied controls, and to determine whether manual examination or ultrasound measures of muscle activation can be accurate alternatives to EMG. Setting: Research center focused on SCI and University laboratory, Vancouver, Canada. Methods: Thirteen people with SCI (11 with American Spinal Injury Association Impairment Scale (AIS) A and 2 AIS B; C4-T5), and 13 matched able-bodied participants volunteered for the study. Participants completed trunk tasks during manual examination of the abdominal muscles and then performed maximal voluntary isometric contractions, while EMG activity and muscle thickness changes were recorded. The frequency of muscle responses detected by manual examination and ultrasound were compared with detection by EMG (sensitivity and specificity). Results: All individuals with SCI were able to elicit EMG activity above resting levels in at least one abdominal muscle during one task. In general, the activation pattern was task specific, confirming voluntary control of the muscles. Ultrasound, when compared with EMG, showed low sensitivity but was highly specific in its ability to detect preserved abdominal muscle function in persons with SCI. Conversely, manual examination was more sensitive than ultrasound but showed lower specificity. Conclusion:The results from this study confirm preserved voluntary abdominal muscle function in individuals classified with motorcomplete SCI above T6 and highlight the need for further research in developing more accurate clinical measures to diagnose the level of trunk muscle preservation in individuals with SCI.

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“…The core muscles maintain the neutral pelvic position on the bike when the anterior and posterior muscle components are equally balanced. On the hasis of orientation and attachment of the psoas muscle on the lumbar spine, pelvic stabilization and resistance to fatigue are critical to maintain the natural curve of the spine as well as provide the leverage from which the psoas and gluteal muscles contract when a greater power output is required (8). Although the lack of core stability would appear to have the greatest influence on the back, lower extremity alignment could also be affected as the foundation from which power is generated becomes compromised (2).…”

Section: Introductionmentioning

confidence: 99%