Document Type
Article
Publication Date
2023
Publisher
Cold Spring Harbor Laboratory
Source Publication
bioRxiv
Original Item ID
DOI: 10.1101/2023.10.24.563851
Abstract
The mechanisms for the loss in limb muscle power in old (60-79 years) and very old (≥80 years) adults and whether the mechanisms differ between men and women are not well-understood. We compared maximal power of the knee extensor muscles between young, old, and very old men and women and identified the neural and muscular factors contributing to the age-related loss of power. 31 young (22.9±3.0 years, 15 women), 83 old (70.4±4.9 years, 39 women), and 16 very old adults (85.8±4.2 years, 9 women) performed maximal isokinetic contractions at 14 different velocities (30- 450°/s) to identify peak power. Voluntary activation (VA) and contractile properties were assessed with transcranial magnetic stimulation to the motor cortex and electrical stimulation of the femoral nerve. The age-related loss in power was ∼6.5 W·year-1 for men (R2=0.62, p< 0.001), which was a greater rate of decline (p=0.002) than the ∼4.2 W·year-1 for women (R2=0.77, p< 0.001). Contractile properties were the most closely associated variables with power output for both sexes, such as the rate of torque development of the potentiated twitch (men: R2=0.69, p< 0.001; women: R2=0.57, p< 0.001). VA was weakly associated with power in women (R2=0.13, p=0.012) but not men (p=0.191), whereas neuromuscular activation (EMG amplitude) during the maximal power contraction was not associated with power in men (p=0.347) or women (p=0.106). These data suggest that the age-related loss in power of the knee extensor muscles is due primarily to factors within the muscle for both sexes, although neural factors may play a minor role in older women.
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Recommended Citation
Wrucke, David; Kuplic, Andrew; Adam, Mitchell; Hunter, Sandra K.; and Sundberg, Christopher W., "Neural and Muscular Contributions to the Age-Related Loss in Power of the Knee Extensors in Men and Women" (2023). Exercise Science Faculty Research and Publications. 222.
https://epublications.marquette.edu/exsci_fac/222
Comments
bioRxiv, 2023. Online before print. DOI.
This version posted October 28, 2023. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granded bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license.