Neuromuscular fatigue reduces force responsiveness when controlling leg external forces
Bibliographic record
Abstract
Agile movement requires precise control of ground reaction forces, yet the impact of neuromuscular fatigue on this control remains incompletely understood. We investigated how leg muscle fatigue affects the nervous system's ability to modulate vertical ground reaction forces, hypothesizing that fatigue would impair responsiveness, and accuracy. Eighteen healthy participants (11 W, 7 M; age: 26 ± 3.8 yr) performed force-matching tasks using a custom apparatus that constrained body movement while allowing isolated leg force production. Participants force matched visual step targets before and after fatigue, which we induced by sustained submaximal contractions. We then quantified responsiveness (rise time, bandwidth) and accuracy (overshoot, steady-state error, variability). Fatigue reduced MVC force by 26.1 ± 12.3% (from 2.95 ± 0.58 to 2.20 ± 0.47 body weights; p = 4.70e-6) and impaired responsiveness, with rise time increasing 23.3 ± 41.0% (from 303 ± 100 to 373 ± 94 ms; p = 6.00e-4) and bandwidth decreasing 25.2 ± 17.5% (from 1.33 ± 0.60 to 1.00 ± 0.25 Hz; p = 4.83e-2). Notably, accuracy remained largely unchanged, with only a transient decrease in overshoot from 4.30 ± 2.62% to 2.56 ± 1.19% (p = 0.047). These findings show neuromuscular fatigue selectively impairs the speed of leg force adjustments while preserving accuracy, possibly through compensatory strategies. This dissociation has implications for understanding motor control deficits and injury risk during fatigue.
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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 | 0.000 | 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) | 0.000 | 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".