Adaptations in antagonist co-activation: Role in the repeated-bout effect

Eccentric exercise results in an adaptation which attenuates muscle damage from subsequent exercise—termed the “repeated-bout effect (RBE).” Purpose: Study examined antagonist co-activation and motor-unit recruitment strategy, assessed via dEMG, concomitant to the RBE. Methods: Nine participants performed 5 sub-maximal isometric trapezoid (ramp-up, hold, ramp-down) contractions at force levels corresponding to 50% and 80% of maximal isometric strength (MVC). Surface EMG signals of the biceps brachii were decomposed into individual motor-unit action potential trains. The relationship between mean firing rate (MFR) of each motor-unit and its recruitment threshold (RT) was examined using linear regression. Eccentric exercise was then performed until biceps brachii MVC had decreased by ~40%. Surface EMG of the biceps and triceps were collected during eccentric exercise. MVC, range-of-motion (ROM), and delayed onset muscle soreness (DOMS) were measured 24-hours, 72-hours, and 1-week following eccentric exercise. Three weeks later all procedures were repeated. Results: Changes in MVC (-32±14% vs -25±10%; p = 0.034), ROM (-11% vs 6%; p = 0.01), and DOMS (31.0±19mm vs 19±12mm; p = 0.015) were attenuated following the second bout of exercise. Triceps EMG was reduced (16.8±9.5% vs. 12.6±7.2%; p = 0.03) during the second bout of eccentric exercise. The slope (-0.60±0.13 vs -0.70±0.18; p = 0.029) and y-intercept (46.5±8.3 vs 53.3±8.8; p = 0.020) of the MFR vs. RT relationship was altered during contractions at 80% of MVC prior to the second bout of eccentric exercise. No changes were observed at 50% of MVC. Conclusion: A reduction in antagonist co-activation during the second bout of eccentric exercise suggests less total force was required to move an identical external load. This finding is supported by the increased negative slope coefficient and an increased y-intercept of the linear relationship between RT and MFR.Funded by University of Oklahoma Graduate College Robberson Grant.Ye

IPUS - AN ARCHITECTURE FOR THE INTEGRATED PROCESSING AND UNDERSTANDING OF SIGNALS

The Integrated Processing and Understanding of Signals (IPUS) architecture is presented as a framework that exploits formal signal processing models to structure the bidirectional interaction between front-end signal processing and signal understanding processes. This architecture is appropriate for complex environments, which are characterized by variable signal to noise ratios, unpredictable source behaviors, and the simultaneous occurrence of objects whose signal signatures can distort each other. A key aspect of this architecture is that front-end signal processing is dynamically modifiable in response to scenario changes and to the need to re-analyze ambiguous or distorted data. The architecture tightly integrates the search for the appropriate front-end signal processing configuration with the search for plausible interpretations. In our opinion, this dual search, informed by formal signal processing theory, is a necessary component of perceptual systems that must interact with c..

Role of Electromyography in Dental Research: A Review

Background and Aim: The purpose of this review was to provide an overview of the use of electromyography (EMG) in dentistry over the past several years, as well as related research. EMG is a sophisticated technique used to detect and analyze muscle activity. EMG was primarily utilized in medical sciences in the past, but it is now widely utilized in both the medical and dental fields.   Materials and Methods: Electronic search was conducted in EMBASE, PubMed, Scopus, Web of Science, and Google Scholar to find all clinical studies regarding applications of EMG in dentistry. Results: This review included 31 papers in all. According to the results, neuromuscular activity may be recorded using EMG for both diagnostic and therapeutic purposes. It could be used in dentistry to evaluate parafunctional habits such as clenching and bruxism as well as muscle activation during actions like chewing and biting. In recent years, the use of EMG in treatment of temporomandibular joint (TMJ) and myofascial pain disorders has significantly increased. Conclusion: EMG has a variety of applications in dentistry for monitoring, diagnostic, and therapeutic purposes