Journal article
Age-related differences in rates of torque development and rise in EMG are eliminated by normalization
Experimental gerontology, Vol.57, pp.18-28
09/2014
DOI: 10.1016/j.exger.2014.04.015
PMID: 24806786
Abstract
The purpose of this study was to compare the voluntary and evoked, absolute and normalized leg extension rates of torque development (RTD) and rates of rise in electromyography (RER) during commonly reported time intervals in young and old men. Fourteen young men (21.9±3.2years) and 16 older men (72.3±7.3years) completed three evoked and three voluntary isometric leg extension muscle actions to quantify absolute voluntary (peak, 30, 50, 100, and 200ms) and evoked (peak, 30, 50, and 100ms) RTD and RER. All RTD values were normalized (nRTD) to peak torque, while RER values were normalized (nRER) to peak-to-peak M-wave amplitude (MPP). Absolute voluntary RTDs and RERs were 58–122% and 70–76% greater (p≤0.05) for the young men, respectively. However, there were no age-related differences (p>0.05) for voluntary nRTDs, absolute and normalized evoked RTDs, or voluntary nRER. MPP and evoked RER and nRER were greater (p≤0.05) for the young men. In addition, voluntary RTD was more reliable in the young than the older men. Normalizing RTD to peak torque and RER to M-wave amplitude eliminated the age-related differences and suggested that the age-related declines in RTD and RER were a result of reduced muscle strength and M-wave amplitude, respectively. Therefore, our findings questioned the value of RTD and RER measurements in the various time intervals for explaining sarcopenia and suggested that maximal strength and M-wave amplitude may be sufficient.
•Absolute voluntary RTD and RER, M-wave RER, and M-wave amplitude were greater in young than old men.•Normalization of voluntary RTD or RER to peak strength and the M-wave amplitude eliminated age-related differences.•M-wave amplitude and rate of rise in the M-wave were lower for the old men.•There are questions regarding the reliability of RTD in older men.
Details
- Title: Subtitle
- Age-related differences in rates of torque development and rise in EMG are eliminated by normalization
- Creators
- Nathaniel D.M Jenkins - University of Nebraska–LincolnSamuel L Buckner - University of Nebraska–LincolnKristen C Cochrane - University of Nebraska–LincolnHaley C Bergstrom - University of Nebraska–LincolnTy B Palmer - Oklahoma State UniversityGlen O Johnson - University of Nebraska–LincolnRichard J Schmidt - University of Nebraska–LincolnTerry J Housh - University of Nebraska–LincolnJoel T Cramer - University of Nebraska–Lincoln
- Resource Type
- Journal article
- Publication Details
- Experimental gerontology, Vol.57, pp.18-28
- DOI
- 10.1016/j.exger.2014.04.015
- PMID
- 24806786
- NLM abbreviation
- Exp Gerontol
- ISSN
- 0531-5565
- eISSN
- 1873-6815
- Publisher
- Elsevier Inc
- Language
- English
- Date published
- 09/2014
- Academic Unit
- Center for Social Science Innovation; Injury Prevention Research Center; Health, Sport, and Human Physiology
- Record Identifier
- 9984259399502771
Metrics
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