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The Electromyographic Threshold in Girls and Women.

Long, D and Dotan, R and Pitt, B and McKinlay, B and O'Brien, TD and Tokuno, C and Falk, B (2016) The Electromyographic Threshold in Girls and Women. Pediatric Exercise Science. ISSN 1543-2920

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Long et al - EMGth in GW - PES - July 11 2016.pdf - Accepted Version

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Abstract

BACKGROUND: The electromyographic threshold (EMGTh) is thought to reflect increased high-threshold/type-II motor-unit (MU) recruitment and was shown higher in boys than in men. Women differ from men in muscular function. PURPOSE: Establish whether females' EMGTh and girls‒women differences are different than males'. METHODS: Nineteen women (22.9±3.3yrs) and 20 girls (10.3±1.1yrs) had surface EMG recorded from the right and left vastus lateralis muscles during ramped cycle-ergometry to exhaustion. EMG root-mean-squares were averaged per pedal revolution. EMGTh was determined as the least residual sum of squares for any two regression-line data divisions, if the trace rose ≥3SD above its regression line. EMGTh was expressed as % final power-output (%Pmax) and %VO2pk power (%PVO2pk). RESULTS: EMGTh was detected in 13 (68%) of women, but only 9 (45%) of girls (p<0.005) and tended to be higher in the girls (%Pmax= 88.6±7.0 vs. 83.0±6.9%, p=0.080; %PVO2pk= (101.6±17.6 vs. 90.6±7.8%, p=0.063). When EMGTh was undetected it was assumed to occur at 100%Pmax or beyond. Consequently, EMGTh values turned significantly higher in girls than in women (94.8±7.4 vs. 88.4±9.9 %Pmax, p=0.026; and 103.2±11.7 vs. 95.2±9.9 %PVO2pk, p=0.028). CONCLUSIONS: During progressive exercise, girls appear to rely less on higher-threshold/type-II MUs than do women, suggesting differential muscle activation strategy.

Item Type: Article
Additional Information: As accepted for publication in Pediatric Exercise Science. http://dx.doi.org/10.1123/pes.2016-0056
Uncontrolled Keywords: 1106 Human Movement And Sports Science, 1114 Paediatrics And Reproductive Medicine, 1302 Curriculum And Pedagogy
Subjects: R Medicine > RC Internal medicine > RC1200 Sports Medicine
Divisions: Sport & Exercise Sciences
Publisher: Human Kinetics
Related URLs:
Date Deposited: 11 Nov 2016 12:23
Last Modified: 07 Sep 2017 15:09
DOI or Identification number: 10.1123/pes.2016-0056
URI: http://researchonline.ljmu.ac.uk/id/eprint/4792

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