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You searched for subject:(Muscles coactivation). Showing records 1 – 2 of 2 total matches.

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Aristotle University Of Thessaloniki (AUTH); Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ)

1. Milosis, Dimitrios. Ειδικές εργαστηριακές μετρήσεις δύναμης για τους καμπτήρες και εκτείνοντες μυς των ώμων στο άθλημα της ενόργανης γυμναστικής.

Degree: 2018, Aristotle University Of Thessaloniki (AUTH); Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ)

The extensive review of the literature revealed a research gap in evaluating the isometric and isokinetic torque and electromyographic (EMG) activity of shoulder’s flexor and extensor muscles in movements adapted to the gymnastics. The aim of the present study was to examine the reliability and the validity of new and original specific laboratory strength measurements of the shoulders' flexor and extensor muscles, when activating both arms simultaneously with the elbows fully extended. Specifically, the study examined isometric and isokinetic torque, conventional (flexors/extensors) and functional (eccentric/concentric) muscles’ strength ratios, EMG activity, neuromuscular efficiency (torque/HMG ratio, NME) and antagonist/agonist co-activation ratio (MCA) of the flexors and extensors of the shoulder joint. In addition, it evaluated the performance on selected gymnastics skills and its relationship to the strength parameters tested in the laboratory. Fifteen high competitive male gymnasts (GYM) and eighteen physical education students (PE) participated voluntarily in the study (age: 19.37 ± 2.27 and 21.27 ± 2.41 years, respectively). To verify the reliability of peak torque (PT) measurements, two identical measurements with one week interval were assessed using the isokinetic Humac Norm 770 dynamometer at three angles (45º, 90º, and 135º) for isometric and at three angular velocities (60º/s, 180º/s, and 300º/s) for isokinetic concentric and eccentric action modes. All isokinetic measurements were conducted in a range of motion of 10º to 180º (anatomical position in 0º, with the arms by the sides of the body and palms facing forward), in supine position, bilaterally, with the elbows fully extended. During isometric and isokinetic torque measurements, the EMG activity of the muscles: anterior deltoid, clavicular head of the pectoralis major and biceps brachil (flexors) and posterior deltoid, latissimus dorsi and long head of the triceps brachil (extensors) was measured at the same time in the Biopac ΜP100 electromyography system. The relative and absolute reliability of isometric and isokinetic dynamometer measurements was supported by the ICC, SEM, SEMe, CV and Bland-Altman analyses. From the examination of the relations between the strength parameters and the performance in the gymnastics skills, the internal and external validity of the measurements was supported. From multivariate analyses of variance (MANOVAs) and multivariate analyses of covariance (MANCOVAs), with physical characteristics and somatometric parameters as covariates, statistically significant higher PT values were obtained for GYM athletes compared to PE students for all variables tested (with some exceptions in which the covariate was the cross-section area of the right arm). On the other hand, statistically significant differences in shoulders F/E ratios (conventional and functional) were not observed. From the results of EMG analyses it appeared that GYM athletes compared to PE students tended to have higher NME values and lower MCA…

Subjects/Keywords: Αξιοπιστία και εγκυρότητα μετρήσεων; Κορύφωση ροπής; Ισοκινητική δυναμομέτρηση; Αναλογία καμπτήρων/εκτεινόντων; Ηλεκτρομυογραφία; Νευρομυϊκή αποδοτικότητα; Συνενεργοποίηση μυών; Άρθρωση ώμων; Δεξιότητες ενόργανης γυμναστικής; Reliability and validity of measurements; Peak torque; Isokinetic dynamometry; Flexor/εxtensor ratios; Electromyography; Neuromuscular efficiency; Muscles coactivation; Shoulder joint; Gymnastics skills

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Milosis, D. (2018). Ειδικές εργαστηριακές μετρήσεις δύναμης για τους καμπτήρες και εκτείνοντες μυς των ώμων στο άθλημα της ενόργανης γυμναστικής. (Thesis). Aristotle University Of Thessaloniki (AUTH); Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ). Retrieved from http://hdl.handle.net/10442/hedi/44161

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Milosis, Dimitrios. “Ειδικές εργαστηριακές μετρήσεις δύναμης για τους καμπτήρες και εκτείνοντες μυς των ώμων στο άθλημα της ενόργανης γυμναστικής.” 2018. Thesis, Aristotle University Of Thessaloniki (AUTH); Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ). Accessed February 25, 2021. http://hdl.handle.net/10442/hedi/44161.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Milosis, Dimitrios. “Ειδικές εργαστηριακές μετρήσεις δύναμης για τους καμπτήρες και εκτείνοντες μυς των ώμων στο άθλημα της ενόργανης γυμναστικής.” 2018. Web. 25 Feb 2021.

Vancouver:

Milosis D. Ειδικές εργαστηριακές μετρήσεις δύναμης για τους καμπτήρες και εκτείνοντες μυς των ώμων στο άθλημα της ενόργανης γυμναστικής. [Internet] [Thesis]. Aristotle University Of Thessaloniki (AUTH); Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ); 2018. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10442/hedi/44161.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Milosis D. Ειδικές εργαστηριακές μετρήσεις δύναμης για τους καμπτήρες και εκτείνοντες μυς των ώμων στο άθλημα της ενόργανης γυμναστικής. [Thesis]. Aristotle University Of Thessaloniki (AUTH); Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ); 2018. Available from: http://hdl.handle.net/10442/hedi/44161

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


East Carolina University

2. Brady, Robert B. Influence of training history and contraction velocity on hamstring muscle coactivation during maximal effort knee extension.

Degree: MS, Exercise and Sports Science, 2012, East Carolina University

When a muscle produces voluntary force, muscles on the opposite side of the joint, the antagonists, are also activated. While coactivation of the knee flexors during knee extension is presumed to increase joint stability by decreasing anterior shear force of the tibia on the femur, the coactivation of the hamstrings also produces what is called the antagonist torque. Systematic exercise in the form of resistance training can reduce antagonist muscle coactivation in healthy young adults. However, the mechanical consequence of this neurological adaptation is unclear. We thus hypothesized that previously strength-trained individuals would exhibit less antagonist coactivation, resulting in a reduced antagonist torque, and that with an increase in contraction speed there would be an increase in antagonist coactivation to slow the movement but there would be less of an increase due to speed in the trained compared with untrained individuals. Therefore, the purpose of this study was to determine the effects of training status on coactivation, i.e., antagonist torque, and on the speed-sensitivity of coactivation. Subjects for this study were fitted with surface EMG electrodes on their thigh muscles, and performed maximal effort knee extensions on a dynamometer, using shortening (concentric) and lengthening (eccentric) contractions at 30, 90, and 150°/s. As expected, trained individuals produced ~44% less coactivation at all contractions speeds. Against the hypothesis, coactivation did not increase in either group as velocity increased, as there was less than 10% difference in coactivation levels between the 3 speeds. Also against the hypothesis, as determined with an EMG-driven mathematical model, antagonist torque did not decrease with decreasing coactivation; in fact we see a trend towards the opposite for trained individuals. A borderline greater antagonist torque was noted in the trained compared to the untrained subjects even with decreased coactivation of the trained. These data suggest that antagonist muscle coactivation is less in trained healthy young adults but this reduced neural activation does not manifest itself in lower levels of antagonist torque. Therefore, leg strength training may increase muscle strength in part by reducing antagonist muscle coactivation without compromising joint stability.   Advisors/Committee Members: Hortobágyi, Tibor (advisor).

Subjects/Keywords: Coactivation; Co-contraction; Electromyography; Torque; Trained; Exercise – Physiological aspects; Physical education and training; Knee – Muscles; Muscle contraction; Biomechanics; Kinesiology

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Brady, R. B. (2012). Influence of training history and contraction velocity on hamstring muscle coactivation during maximal effort knee extension. (Masters Thesis). East Carolina University. Retrieved from http://hdl.handle.net/10342/3949

Chicago Manual of Style (16th Edition):

Brady, Robert B. “Influence of training history and contraction velocity on hamstring muscle coactivation during maximal effort knee extension.” 2012. Masters Thesis, East Carolina University. Accessed February 25, 2021. http://hdl.handle.net/10342/3949.

MLA Handbook (7th Edition):

Brady, Robert B. “Influence of training history and contraction velocity on hamstring muscle coactivation during maximal effort knee extension.” 2012. Web. 25 Feb 2021.

Vancouver:

Brady RB. Influence of training history and contraction velocity on hamstring muscle coactivation during maximal effort knee extension. [Internet] [Masters thesis]. East Carolina University; 2012. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10342/3949.

Council of Science Editors:

Brady RB. Influence of training history and contraction velocity on hamstring muscle coactivation during maximal effort knee extension. [Masters Thesis]. East Carolina University; 2012. Available from: http://hdl.handle.net/10342/3949

.