Proceedings of the Canadian Society for Exercise Physiology Annual General Meeting: CSEP 2020 Online! Enhancing our Performance, Keeping our Connections
Bibliographic record
Abstract
Dietary amino acids (AA) are incorporated into myofibrillar (contractile) proteins for up to 24h after resistance exercise (RE) in lab-based settings, although the impact of training on the reliance for these dietary substrates is unknown.The translocation and colocalization of mechanistic target of rapamycin (mTOR) with regulatory proteins is purported to be critical for translation initiation after anabolic stimuli.We examined how training status and mTOR regulation modulates the RE-induced incorporation of dietary protein into muscle tissue protein over 24h in a free-living setting.Ten recreationally active men (age: 22±3yr; means±SD) underwent 8 weeks of whole-body RE 3x/week.Muscle biopsies were obtained immediately before-(REST) and 24h after-an acute bout of RE in the untrained (UT) and trained (T) state while consuming crystalline AA, mixed macronutrient diets containing 1.6g protein/kg/d.Dietary AA incorporation into the myofibrillar protein fraction (LC/MS/MS) was determined by labelling the diet with [ 2 H 5 ]-phenylalanine or [ 13 C 6 ]-phenylalanine.mTOR regulation was determined by immunofluorescence microscopy and immunoblotting.Resistance training elevated mTOR colocalization with WGA (sarcolemma marker), LAMP2 (lysosomal marker), UEA-1 (capillary marker) and Rheb (direct activator) by 10-23% (training effect, all P<0.05).Resting LAMP2-WGA colocalization was increased by ϳ10% in T (P<0.05) and Rheb-WGA colocalization increased by ϳ10% (training effect; P<0.05).Total mTOR and LAMP2 protein content increased in T by ϳ43 (P<0.05) and ϳ20% (P=0.063),respectively (training effect).RE increased dietary phenylalanine incorporation above REST in UT and T by 41 and 21%, respectively (P<0.05) and was lower in T compared to UT (ϳ14%.P=0.015).An enhanced proximity of the mTOR-Rheb-lysosomal protein complex to the sarcolemma and capillaries after training could suggest an enhanced capacity for muscle protein remodeling contributing to reduced reliance on exogenous AA to facilitate myofibrillar remodeling in the trained state.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.716 | 0.405 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".