Low Energy Availability Followed by Optimal Energy Availability Does Not Benefit Performance in Trained Females
Bibliographic record
Abstract
PURPOSE: Short periods of reduced energy availability are commonly undertaken by athletes to decrease body mass, possibly improve the power-to-mass ratio, and enhance physical performance. Our primary aim was to investigate the impact of 10 d of low energy availability (LEA) followed by 2 d of optimal energy availability (OEA) on physical performance parameters in trained females. Second, physiological markers at the whole-body and molecular level related to performance were evaluated. METHODS: Thirty young trained eumenorrheic females were matched in pairs based on training history and randomized to a 10-d intervention period of LEA (25 kcal·fat-free mass (FFM) -1 ·d -1 ) or OEA (50 kcal·FFM -1 ·d -1 ) along with supervised exercise training. Before the intervention, participants underwent a 5-d run-in period with OEA + supervised exercise training. After the LEA intervention, 2 d of recovery with OEA was completed. Participants underwent muscle biopsies, blood sampling, physical performance tests, body composition measurements, and resting metabolic rate measurements. A linear mixed model was used with group and time as fixed effects and subject as random effects. RESULTS: Compared with OEA, LEA resulted in reduced body mass, muscle glycogen content, repeated sprint ability, 4-min time-trial performance, and rate of force development of the knee extensors (absolute values; P < 0.05). Two days of recovery restored 4-min time-trial performance and partly restored repeated sprint ability, but performance remained inferior to the OEA group. When the performance data were expressed relative to body mass, LEA did not enhance performance. CONCLUSIONS: Ten days of LEA resulted in impaired performance (absolute values), with concomitant reductions in muscle glycogen. Two days of recovery with OEA partially restored these impairments, although physical performance (absolute values) was still inferior to being in OEA. Our findings do not support the thesis that LEA giving rise to small reductions in body mass improves the power-to-mass ratio and thus increases physical performance.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot 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.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.004 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 teacher head, 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".