The Effect of Isometric Training on Muscle-Tendon Unit Stiffness of Medial Gastrocnemius and the Economy of Locomotion in Highly-Trained Distance Runners
Bibliographic record
Abstract
Previous studies have shown that economy of locomotion (E) is influenced by the mechanical and morphological properties of the muscle-tendon unit (MTU) of lower limbs. It has also been shown previously that these properties can be changed with isometric training (IT); however, it is not yet known if changes induced by IT result in a change in E in a group of highly-trained distance runners. PURPOSE: To determine the change in the mechanical and morphological properties of MTU of the medial gastrocnemius (MG) after 8 weeks of IT and if these changes result in a change in E in a group of highly-trained distance runners. METHODS: 6 highly-trained male distance runners (22±4yrs, 183±1cm, 72±6kg; VO2max=68±3ml·kg−1·min−1) completed an E test consisting of 5 minutes at 75, 85 and 95% of velocity corresponding to lactate threshold (vLT), both before and after 8 weeks of IT. E was measured using a metabolic cart and expressed as kcal·kg−1·km−1. IT consisted of 4×20 seconds isometric plantarflexions (PF) at 80% PFmax, 3×/wk for 8 weeks on an isokinetic dynamometer. MTU stiffness (K), thickness and pennation angle was measured using ultrasound. MTU properties and 80%max was measured every 2 weeks throughout IT. RESULTS: PFmax, K, and MTU elongation increased from baseline following IT (36±29%, p<0.10, 41±36%, p<0.10, 21±13%, p<0.10, 7±3%, p<0.08). There was no change in E at either the 75% or 85% vLT, but E at 95% vLT was improved from baseline (7±3%, p<0.08) following IT. CONCLUSIONS: 8 weeks of IT resulted in increases in PF strength and MTU stiffness of the medial gastrocnemius. Concurrently, running economy improved, but only at the highest velocity tested. Supported by NSERC Canada.
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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 | 0.000 |
| 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) | 0.001 | 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".