Ankle intrinsic stiffness is modulated by postural sway
Bibliographic record
Abstract
Dynamic ankle stiffness, which defines the relationship between joint position and the torque acting about it, determines the joint resistance to external perturbations. The contribution of joint stiffness to stance control is usually assumed to be constant; however, the stiffness may be modulated due to the ongoing sway during stance. This paper describes the results of the direct estimation of ankle intrinsic stiffness and its modulation with background torque during stance. Three subjects stood on a standing apparatus, while subjected to pulse perturbations of ankle position. The angle of center of mass, and ankle torque and angle were measured and individual torque responses to each position perturbation were analyzed. Each response lasted 90 milliseconds, where the mean of the torque record in the first 25 milliseconds was considered as its background torque. Ensemble of the responses with similar background torques were used to estimate the joint intrinsic stiffness. The estimated parameters showed that elastic element of the ankle intrinsic stiffness varied significantly (by a factor of 3) with background torque, i.e. the higher the background torque, the higher the stiffness. Thus ankle stiffness is not constant but varies greatly with postural sway.
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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 | 0.000 | 0.002 |
| 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) | 0.001 | 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 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".