INDIVIDUALS WITH CHRONIC STROKE DEMONSTRATE MUSCLE TORQUE-ANGLE IMPAIRMENT IN THE PARETIC KNEE AND COMPENSATORY STRENGTH GAINS IN THE NONPARETIC KNEE.
Bibliographic record
Abstract
PURPOSE/HYPOTHESIS: Recent reports suggest that the paretic arm of individuals with stroke produces lower elbow flexion and extension torques (when normalized to peak torque) at short muscle lengths when compared to individuals without stroke. Thus the purpose of this study was to determine whether this phenomenon also exists in the paretic and non-paretic knee when assessed across multiple joint angles. NUMBER OF SUBJECTS: Sixteen subjects with chronic stroke and 14 age-matched control subjects without stroke were voluntarily recruited from the community. MATERIALS/METHODS: Maximal isometric knee extension and flexion joint torques were measured at six different angles (15, 35, 55, 75, 95, and 105 degrees). Due to the high variability of muscle weakness, both between and within subjects, each subject's data points were normalized and expressed as a percentage of their own peak torque. Mean normalized extension and flexion torque-angle curves of the paretic and nonparetic knee were compared with each other and with the nondominant knee of control subjects using a two-factor (subject group, knee joint angle) mixed design analysis of variance (ANOVA). If significant subject group by joint angle interactions were revealed, post-hoc pairwise comparisons with a Bonferonni adjustment were performed to determine relative muscle strength of the paretic, nonparetic, and control conditions at each angle tested. RESULTS: The ANOVA revealed a significant interaction between subject group (paretic, nonparetic, and control) and knee joint angle for the extensors (P = .002), but not the flexors (P = .386). Post-hoc tests for the extensors revealed the paretic knee to be relatively weaker than the control knee at 15 degrees of flexion (i.e. short muscle lengths) (P = .006). In addition, the nonparetic knee was relatively stronger than the control knee at 95 (P = .004) and 105 (P = .007) degrees of flexion (i.e. long muscle lengths). CONCLUSIONS: The results of this work suggest that the paretic knee extensors are selectively weak when required to contract at short muscle lengths. This agrees with the clinical observation that the quadriceps is more severely impaired as the knee joint approaches terminal extension, particularly during gait. In addition, the nonparetic quadriceps is selectively stronger than the control quadriceps when required to contract at long muscle lengths; suggesting individuals with stroke compensate through overuse of the nonparetic side during functional activities such as sit-to-stand and stair climbing. This learned nonuse of the paretic leg leads to a task specific increase in quadriceps strength of the nonparetic knee at long muscle lengths. CLINICAL RELEVANCE: Rehabilitation interventions should emphasize paretic knee strengthening near terminal extension and encourage symmetrical use of the paretic and nonparetic legs to enhance recovery of strength throughout functional range of motion.
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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 | 0.001 | 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 | 0.001 |
| 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".