KINETIC AND ELECTROMYOGRAPHIC CHANGES ASSOCIATED WITH AN ANTERIOR CRUCIATE LIGAMENT DEFICIENCY DURING STATIONARY CYCLING
Bibliographic record
Abstract
Reduced quadriceps muscle activation and net knee joint extensor moments have been recorded in anterior cruciate ligament (ACL) deficient limbs during the mid-stance phase of gait. This has been termed “quadriceps avoidance” (QA) and is hypothesized as a mechanism to maintain knee joint stability by reducing anterior tibial translation. It is unclear whether rehabilitation cycling exercises play a role in the development of this QA strategy. PURPOSE To determine the effect of an ACL deficiency on lower-limb biomechanics during stationary cycling. METHODS 10 unilateral ACL-deficient individuals and 10 age- and gender-matched controls performed six randomized one-minute bouts of stationary cycling at two cadences (60 and 90 rpm) and three power outputs (75, 125, and 175 W). Surface EMG were collected bilaterally from rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), semitendinosis (ST), and gluteus maximus (GM). Kinematic and kinetic data were collected bilaterally and combined to calculate net joint moments of force at the hip, knee, and ankle. Linear impulse was calculated from the resultant pedal force. Statistical analysis was performed using a 4 (limb) x 2 (cadence) x 3 (power output) repeated measures ANOVA with an alpha-level of 0.01. RESULTS In ACL-deficient limbs, decreased peak net knee joint extensor moments, significantly reduced RF and VL activation levels, and no change in ST or BF activity, indicated a QA strategy. However, significant reductions were also exhibited in peak knee flexor, hip extensor, and ankle plantarflexor moments, linear impulse, and GM muscle activity in ACL-deficient limbs compared to ACL-intact limbs, implying a desire to reduce force production over the entire injured limb. CONCLUSIONS ACL-injured individuals exhibited reduced joint moments at each lower-limb joint, which was compensated for by increasing the output from the ACL-intact limb. This apparent limb attenuation strategy may play a role in the development of a QA strategy during walking.
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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 | 0.001 |
| 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".