Electromyographic measures of muscle activation and changes in muscle architecture of human elbow flexors during fatiguing contractions

Thorsten Rudroff; Didier Staudenmann; Roger M Enoka

doi:10.1152/japplphysiol.01058.2007

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Electromyographic measures of muscle activation and changes in muscle architecture of human elbow flexors during fatiguing contractions

Journal article

Open access

Peer reviewed

Electromyographic measures of muscle activation and changes in muscle architecture of human elbow flexors during fatiguing contractions

Thorsten Rudroff, Didier Staudenmann and Roger M Enoka

Journal of applied physiology (1985), Vol.104(6), pp.1720-1726

06/2008

DOI: 10.1152/japplphysiol.01058.2007

PMID: 18356480

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Abstract

The study compared changes in intramuscular and surface recordings of EMG amplitude with ultrasound measures of muscle architecture of the elbow flexors during a submaximal isometric contraction. Ten subjects performed a fatiguing contraction to task failure at 20% of maximal voluntary contraction force. EMG activity was recorded in biceps brachii, brachialis, and brachioradialis muscles using intramuscular and surface electrodes. The rates of increase in the amplitude of the surface EMG for the long and short heads of biceps brachii and brachioradialis were greater than those for the intramuscular recordings measured at different depths. The amplitude of the intramuscular recordings from three muscles increased at a similar rate (P = 0.13), as did the amplitude of the three surface recordings from two muscles (P = 0.83). The increases in brachialis thickness (27.7 +/- 5.7 to 30.9 +/- 3.5 mm; P < 0.05) and pennation angle (10.9 +/- 3.5 to 16.5 +/- 4.8 degrees ; P = 0.003) were not associated with the increase in intramuscular EMG amplitude (P > 0.58). The increase in brachioradialis thickness (22.8 +/- 4.8 to 25.5 +/- 3.4 mm; P = 0.0075) was associated with the increase in the amplitude for one of two intramuscular EMG signals (P = 0.007, r = 0.79). The time to failure was more strongly associated with the rate of increase in the amplitude of the surface EMG than that for the intramuscular EMG, which suggests that the surface measurement provides a more appropriate measure of the change in muscle activation during a fatiguing contraction.

Reproducibility of Results

Humans

Muscle, Skeletal - diagnostic imaging

Ultrasonography

Adult

Isometric Contraction

Male

Muscle, Skeletal - physiology

Electromyography - methods

Elbow

Muscle Fatigue

Details

Title: Subtitle: Electromyographic measures of muscle activation and changes in muscle architecture of human elbow flexors during fatiguing contractions
Creators: Thorsten Rudroff - Dept. of Integrative Physiology, Univ. of Colorado, Boulder, CO 80309-0354, USA. thorsten.rudroff@colorado.edu
Didier Staudenmann
Roger M Enoka
Resource Type: Journal article
Publication Details: Journal of applied physiology (1985), Vol.104(6), pp.1720-1726
DOI: 10.1152/japplphysiol.01058.2007
PMID: 18356480
NLM abbreviation: J Appl Physiol (1985)
ISSN: 8750-7587
eISSN: 1522-1601
Publisher: United States
Grant note: NS-043275 / NINDS NIH HHS
Language: English
Date published: 06/2008
Academic Unit: Neurology; Health, Sport, and Human Physiology
Record Identifier: 9984001105702771

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