Hypothesis: We compared two means of mitigating the effect of sternocleidomastoid (SCM) contraction strength on the cervical vestibular evoked myogenic potential (cVEMP): contraction matching and amplitude normalization.
Background: SCM muscle contraction strength affects the amplitude of the cVEMP which can impact measures of inter-side asymmetry and diagnostic outcomes.
Methods: In 19 normal subjects, we investigated the effect of muscle contraction variation within a cVEMP recording. We then compared cVEMP recordings on the right and left sides with matched and unmatched muscle contraction strength using raw amplitudes and amplitude ratios (i.e., normalized amplitudes).
Results: Contraction variability had significant effects on small sections of a cVEMP recording, but there was no significant effect on overall cVEMP amplitude, suggesting that the cVEMP is relatively unaffected by variable effort during a recording. Matching the contraction across the two sides (d = 0.53, p = 0.016) and amplitude normalization (d = 0.43, p = 0.004) both significantly reduced inter-side asymmetry, but normalization had no additional benefit once the sides were matched (interaction effect, p = 0.019). cVEMPs recorded with matched contractions had the smallest range of asymmetry values.
Conclusion: The study shows that controlling the background contraction during a cVEMP recording, either by using similar contractions for each trial or by normalizing the amplitude, reduces cVEMP asymmetry and can prevent incorrect results in the minority of subjects who make asymmetric muscle contractions.
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http://dx.doi.org/10.1097/MAO.0000000000003316 | DOI Listing |
Int J Sports Physiol Perform
January 2025
Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.
Purpose: Maximal muscle strength is often assessed with single-joint or repetition-maximum testing. The purpose of this study was to evaluate the reliability of countermovement-jump (CMJ) velocity-load testing and assess the relationship between CMJ velocity-load kinetics and concentric-isometric-eccentric multijoint leg-extension strength tested on a robotic servomotor leg press in trained athletes.
Methods: University athletes (N = 203; 52% female) completed 3 concentric, isometric, and eccentric maximum voluntary leg-extension contractions on the robotic leg press, followed by CMJ velocity-load testing with an additional external load of 0% (CMJBW), 30% (CMJ30), and 60% (CMJ60) of body mass.
Acta Bioeng Biomech
September 2024
Institute of Advanced Research for Sport and Health Science, Ritsumeikan University, Japan.
: Toe flexor strength (TFS) has been determined to evaluate the toe flexor muscle function. However, it is unclear how strength and size relationships of toe flexor muscles vary depending on the toes intended for force production. We aimed to clarify this by examining the relationship between TFS and toe flexor muscle size, and hypothesized TFS produced by all toes (TFS-All), the great toe (TFS-Great) and lesser toes (TFS-Lesser) would be specifically associated with the size of the muscles specialized in each corresponding toe flexion.
View Article and Find Full Text PDFJ Gen Physiol
March 2025
Department of Animal, Veterinary, and Food Sciences, College of Agricultural and Life Sciences, University of Idaho, Moscow, ID, USA.
The mechanisms underlying cooperative activation and inactivation of myocardial force extend from local, near-neighbor interactions involving troponin-tropomyosin regulatory units (RU) and crossbridges (XB) to more global interactions across the sarcomere. To better understand these mechanisms in the hearts of small and large mammals, we undertook a simplified mathematical approach to assess the contribution of three types of near-neighbor cooperative interactions, i.e.
View Article and Find Full Text PDFPurpose: This study defines correlative and causal relationships between muscle strength and size before and after unilateral resistance training (RT) in a large cohort of healthy adults, focusing on sex differences within these relationships.
Methods: Results from 1233 participants (504 males and 729 females) in a retrospective analysis were included. Maximal voluntary isometric contraction strength (MVC), one-repetition maximum strength (1RM), biceps cross-sectional area (CSA) and elbow flexor volume (VOL) measures of the non-dominant and dominant arm were evaluated from baseline and after 12-wk RT twice per week.
Digit Health
January 2025
Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Jongno-gu, Seoul, Korea.
Objective: Accurate measurement of pelvic floor muscle (PFM) strength is crucial for the management of pelvic floor disorders. However, the current methods are invasive, uncomfortable, and lack standardization. This study aimed to introduce a novel noninvasive approach for precise PFM strength quantification by leveraging extracorporeal surface perineal pressure (ESPP) measurements and machine learning algorithms.
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