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Motor unit number and transmission stability in octogenarian world class athletes: Can age-related deficits be outrun?

2016· article· en· W2304118364 on OpenAlex
Geoffrey A. Power, Matti D. Allen, Kevin J. Gilmore, Daniel W. Stashuk, Timothy J. Doherty, Russell T. Hepple, Tanja Taivassalo, Charles L. Rice

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.
fundA Canadian funder is recorded on the work.

Bibliographic record

VenueJournal of Applied Physiology · 2016
Typearticle
Languageen
FieldEngineering
TopicMuscle activation and electromyography studies
Canadian institutionsUniversity of WaterlooMcGill UniversityChristie (Canada)Western UniversityQueen's UniversityUniversity of Guelph
FundersCanadian Institutes of Health ResearchNatural Sciences and Engineering Research Council of CanadaGovernment of CanadaMcGill University
KeywordsIsometric exerciseMotor unitNeuromuscular transmissionElectromyographyMedicineReinnervationCardiologyPhysical medicine and rehabilitationInternal medicineAnatomy

Abstract

fetched live from OpenAlex

Our group has shown a greater number of functioning motor units (MU) in a cohort of highly active older (∼65 yr) masters runners relative to age-matched controls. Because of the precipitous loss in the number of functioning MUs in the eighth and ninth decades of life it is unknown whether older world class octogenarian masters athletes (MA) would also have greater numbers of functioning MUs compared with age-matched controls. We measured MU numbers and neuromuscular transmission stability in the tibialis anterior of world champion MAs (∼80 yr) and compared the values with healthy age-matched controls (∼80 yr). Decomposition-enhanced spike-triggered averaging was used to collect surface and intramuscular electromyography signals during dorsiflexion at ∼25% of maximum voluntary isometric contraction. Near fiber (NF) MU potential analysis was used to assess neuromuscular transmission stability. For the MAs compared with age-matched controls, the amount of excitable muscle mass (compound muscle action potential) was 14% greater (P < 0.05), there was a trend (P = 0.07) toward a 27% smaller surface-detected MU potential representative of less collateral reinnervation, and 28% more functioning MUs (P < 0.05). Additionally, the MAs had greater MU neuromuscular stability than the controls, as indicated by lower NF jitter and jiggle values (P < 0.05). These results demonstrate that high-performing octogenarians better maintain neuromuscular stability of the MU and mitigate the loss of MUs associated with aging well into the later decades of life during which time the loss of muscle mass and strength becomes functionally relevant. Future studies may identify the concomitant roles genetics and exercise play in neuroprotection.

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Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.921
Threshold uncertainty score0.412

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.016
GPT teacher head0.220
Teacher spread0.205 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it