INFLUENCE OF SEX AND MUSCLE ACTION ON MECHANOMYOGRAPHIC MEAN POWER FREQUENCY OF THE VASTUS LATERALIS
Bibliographic record
Abstract
Sergio Perez Jr.1, Stephanie Sontag1, Trent Herda2, Adam Sterczala3, Jonathan Miller2, Mandy Parra4, Hannah Dimmick5, Michael A. Trevino1 1Oklahoma State University, Stillwater, Oklahoma; 2University of Kansas, Lawrence, Kansas; 3University of Pittsburgh, Pittsburgh, Pennsylvania; 4Baker University, Baldwin City, Kansas; 5University of Calgary, Calgary, Alberta PURPOSE: To examine mechanomyographic mean power frequency (MMGMPF)-torque relationships for the vastus lateralis (VL) in sedentary males and females. METHODS: Eleven females (mean ± SD; age = 22.7 ± 5.5 yrs) and eight sedentary males (age=19.4 ± 0.7 yrs) volunteered for this study. An MMG sensor was placed over the VL and subcutaneous fat (sFAT) was measured via ultrasonography at the sensor site. Participants completed 3 isometric maximal voluntary contractions (MVCs) of the knee extensors on an isokinetic dynamometer followed by an isometric trapezoid muscle action at 40% MVC. For linearly increasing and decreasing muscle actions, linear regressions models were fit to the log-transformed MMGMPF-force relationship and the slope (b term) was calculated. MMGMPF was averaged during the steady force segment. A 2way mixed factorial ANOVA (sex [male vs. female] x segment [ramp up vs. ramp down]) examined differences in the b terms during the linearly increasing and decreasing muscle actions. Independent samples t-tests examined sex-related differences in skinfold measurements and MMGMPF during steady torque. Pearson’s product moment correlations were used to determine relationships among sFAT and the b terms and MMGMPF. Alpha was set at 0.05. RESULTS: For the b terms, there was no significant two way interaction (p = 0.714) or main effect for sex (p = 0.259). There was a significant main effect for segment (p = 0.001). The b terms were greater during the linearly increasing (0.154 ± 0.131) than decreasing (0.006 ± 0.113) segment when collapsed across sex. During steady torque, MMGMPF was significantly greater (p = 0.002) for males (26.36 ± 2.57 Hz) than females (20.91 ± 3.64 Hz), while sFAT was significantly greater (p = 0.001) for females (1.59 ± 0.69 cm) than males (0.57 ± 0.32 cm). sFAT was significantly correlated with MPF during the plateau (p < 0.001, r = -0.736), but not the b terms for either segment (p > 0.05). CONCLUSION: MMGMPF distinguished between muscle activation and deactivation strategies, but not between sexes. MMGMPF during steady torque was greater for males; however, this may be due to the influence sFAT low-pass filtering the MMG signal to a greater extent for females. Higher targeted torques may be necessary to distinguish muscle activation and deactivation strategies between sexes.
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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".