Leucine Supplementation Does Not Attenuate Metabolic Or Functional Declines Following 7-days Of Unilateral Lower-limb Immobilisation.
Bibliographic record
Abstract
Unavoidable periods of physical inactivity (i.e. illness/injury) lead to muscle atrophy and functional declines, which likely stem from alterations in both anabolic signaling processes and oxidative metabolism. Preventing such declines is important to reduce the risk of re-injury and preserve musculoskeletal health across the lifespan. PURPOSE: To determine the effectiveness of high-dose leucine supplementation to preserve muscle mass, strength, and morphology following 7-days of unilateral knee immobilisation. METHODS: Sixteen healthy, recreationally active males (23±1yrs) underwent 7-days of unilateral knee immobilisation, with (LEU; n=8) or without (PLA; n=8) thrice daily leucine supplementation (15g/d). Strength and compartmental tissue composition were assessed prior to and following immobilisation. Muscle biopsy samples obtained immediately following immobilisation were used to determine muscle fibre morphology as well as key indicators of mitochondrial function between the control (CTL) and immobilised (IMB) limbs. RESULTS: Leg fat-free mass was reduced in the IMB leg following immobilisation (-3.6±0.5%; P<0.05) in both the LEU and PLA conditions (P>0.05), with no such alterations noted in the CTL leg (-0.6±0.5%; P>0.05). Isometric knee extensor strength declined following immobilisation (P<0.01), with a greater (P<0.05) and equivocal decline in the IMB (-27.9±4.4%) vs. CTL (-14.3±4.4%) leg in both the LEU and PLA group (P>0.05). Following immobilisation, type II fibre cross sectional area was significantly lower in the IMB vs. CTL limb (5561.49±465.97 vs. 6319.9±412.9μm2; P<0.05) but not in type I fibre cross sectional area (4805.5±324.3 vs. 5424.95±323.63μm2; P>0.05), with no differences between treatment groups (P>0.05). A significant Group*Leg interaction was identified for mitochondrial complex I phosphorylating respiration (Pi; P<0.05). However, post-hoc analysis revealed no differences in Pi in the IMB vs. CTL limb in either the PLA (FC=1.20±0.19, P=0.06) or LEU (FC=0.87±0.27, P=0.87) group. CONCLUSION: Leucine supplementation, even at a high-dose (15g/d), does not appear to attenuate declines in leg fat-free mass, strength, muscle morphology or mitochondrial respiration following 7-days of unilateral knee immobilisation.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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.
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".